diff --git a/crates/app-iced/src/components/buttons/assemble.rs b/crates/app-iced/src/components/buttons/assemble.rs
index 5314e8e..10b00f3 100644
--- a/crates/app-iced/src/components/buttons/assemble.rs
+++ b/crates/app-iced/src/components/buttons/assemble.rs
@@ -2,6 +2,9 @@
 //!
 //! 单独成文件的原因：`mod.rs` 已经是「对外契约 + 变体角色表」，把绘制细节放一起会顶到 400 行红线；
 //! 而且这条产线是**唯一**会把「令牌 → 像素」翻一次的地方，独立出来才好审。
+//!
+//! 禁用态的合成底（[`Base`]，M234）也从这里往下传：`Button::base(..)` → [`StyleSpec::base`] →
+//! `disabled_button_colors` / `disabled_button_content`。装配侧没有第二个猜底色的地方。
 
 use iced::widget::text::LineHeight;
 use iced::widget::{button, text, Row};
@@ -14,9 +17,9 @@ use unlucky_design::shape::ShapeScale;
 use crate::icons;
 use crate::theme::Ui;
 
-use super::super::interaction::{self, Interaction};
+use super::super::interaction::{self, Base, Interaction};
 use super::super::layout;
-use super::{Geometry, Variant};
+use super::{Button, Geometry, Variant};
 
 /// 一个按钮样式要的全部输入（避免 `style_closure` 长出七个位置参数）。
 #[derive(Debug, Clone, Copy)]
@@ -33,6 +36,12 @@ pub(crate) struct StyleSpec {
     pub stroke: f32,
     /// 圆角折算用的边长（药丸 = 可见高）。
     pub radius_side: f32,
+    /// **脚下那一层的底**（M234）：禁用态的 10% 容器与 38% 内容都叠在它上面。
+    ///
+    /// 由构造点给（卡片 = `surfaces::elevated::BASE`、菜单项 = `inputs::menu::PANEL_BASE`、
+    /// 直接摆在画布上 = [`Base::CANVAS`]）。M229 之前这里恒为 `Role::Surface`，
+    /// 卡片里的禁用按钮因此把 10% 叠在画布色上（M223 的「形丢失」）。
+    pub base: Base,
     /// 强制态（gallery 取证）；`None` = 跟随运行期的 `button::Status`。
     ///
     /// **`Some(Enabled)` 与 `None` 不是一回事**：截图取证必须能强制「静息」，否则光标恰好停在
@@ -45,15 +54,11 @@ pub(crate) struct StyleSpec {
 pub(super) fn assemble<'a, M: Clone + 'a>(
     ui: &'a Ui,
     variant: Variant,
-    spec: super::Button<'a, M>,
+    spec: Button<'a, M>,
 ) -> Element<'a, M> {
     let geometry = Geometry::sized(ui, variant, spec.leading.is_some(), spec.size);
-    let (fill, content, border) = variant.roles();
-    let forced = spec.state.or(if spec.on_press.is_none() {
-        Some(Interaction::Disabled)
-    } else {
-        None
-    });
+    let (fill, content, _border) = variant.roles();
+    let forced = spec.forced();
 
     // 按钮家族没有浮层级高程：L1（Elevated）只用容器色调差表达（rubric §7 不画阴影）
     debug_assert!(
@@ -67,7 +72,14 @@ pub(super) fn assemble<'a, M: Clone + 'a>(
     // 早先这里恒取 `ui.color(content)`，再被 `text(...).color(..)` 钉死，`Style.text_color`
     // 里的 38% 永远下发不出去 —— 表现为「text / standard icon 的 enabled 格与 disabled 格
     // 逐像素相同」（视觉 reviewer 实测 changed_px = 0；filled 禁用标签 1.23:1）。
-    let ink = content_color(ui, forced, content, fill, variant.disabled_content());
+    let ink = content_color(
+        ui,
+        spec.base,
+        forced,
+        content,
+        fill,
+        variant.disabled_content(),
+    );
 
     // 标签排版跟尺寸档走：`ControlSize::label()` 已把「字号跟字级、字重固定 500」定死
     // （XS/S = LabelLarge 14、M = BodyLarge 16、L = HeadlineSmall 24、XL = HeadlineLarge 32）。
@@ -106,18 +118,7 @@ pub(super) fn assemble<'a, M: Clone + 'a>(
         .height(Length::Fill)
         .align_y(iced::Alignment::Center);
 
-    let style = style_closure(
-        ui,
-        StyleSpec {
-            fill,
-            content,
-            border,
-            shape: variant.shape(),
-            stroke: geometry.stroke,
-            radius_side: geometry.height,
-            forced,
-        },
-    );
+    let style = style_closure(ui, text_style_spec(ui, variant, &spec));
 
     let element = button(content_box)
         .height(Length::Fixed(geometry.height))
@@ -130,6 +131,26 @@ pub(super) fn assemble<'a, M: Clone + 'a>(
     }
 }
 
+/// `Button` → 样式描述：**装配的唯一接线点**（`assemble` 与单测都走这里）。
+///
+/// 抽出来的理由与 [`super::icon_style_spec`] 同源：`button::Style` 是闭包、`Element` 是黑盒，
+/// 两者都不可内省，所以「禁用态的底到底传了哪一个」只能在**结构体**上断言。
+/// 写死一个 `StyleSpec` 再喂给 `style_closure` 的测试证明不了接线（M229 复审 P1-1 踩过）。
+pub(super) fn text_style_spec<M>(ui: &Ui, variant: Variant, spec: &Button<'_, M>) -> StyleSpec {
+    let (fill, content, border) = variant.roles();
+    let geometry = Geometry::sized(ui, variant, spec.leading.is_some(), spec.size);
+    StyleSpec {
+        fill,
+        content,
+        border,
+        shape: variant.shape(),
+        stroke: geometry.stroke,
+        radius_side: geometry.height,
+        base: spec.base,
+        forced: spec.forced(),
+    }
+}
+
 /// 内容色（文字与图标共用）：禁用态走令牌的 38%，其余态就是角色色。
 ///
 /// 单独成函数是为了让「内容色跟态走」这件事只有一处实现——`assemble`（文字按钮）与 `icon`
@@ -139,19 +160,20 @@ pub(super) fn assemble<'a, M: Clone + 'a>(
 /// 其余是 `OnSurfaceVariant`，不能在这里统一写死。
 pub(super) fn content_color(
     ui: &Ui,
+    base: Base,
     forced: Option<Interaction>,
     content: Role,
     fill: Option<Role>,
     disabled_content: Role,
 ) -> iced::Color {
     match forced {
-        // 有容器：38% 叠在**按钮家族 10% 容器**上（Filled / Tonal / Elevated）
+        // 有容器：38% 叠在**按钮家族 10% 容器**上（Filled / Tonal / Elevated），容器再叠在 `base` 上
         Some(Interaction::Disabled) if fill.is_some() => {
-            interaction::disabled_button_content(ui, disabled_content, true)
+            interaction::disabled_button_content(ui, base, disabled_content, true)
         }
-        // 无容器：38% 直接叠在 **surface** 上（Text / Outlined / standard IconButton）
+        // 无容器：38% 直接叠在 **base** 上（Text / Outlined / standard IconButton）
         Some(Interaction::Disabled) => {
-            interaction::disabled_button_content(ui, disabled_content, false)
+            interaction::disabled_button_content(ui, base, disabled_content, false)
         }
         _ => ui.color(content),
     }
@@ -168,28 +190,35 @@ pub(super) fn style_closure(
             .forced
             .unwrap_or_else(|| Interaction::from_status(status));
 
-        let (background, text_color) = if state.is_disabled() {
-            let (container, content) = interaction::disabled_button_colors(ui, Role::Surface);
-            // 透明容器在禁用态依然透明（官方只改内容透明度）
-            (spec.fill.map(|_| container), content)
-        } else {
-            // 有填充：状态层叠在**容器角色**上；透明容器：叠在表面色上（否则 hover 看不见）
-            let background = match spec.fill {
-                Some(role) => match state.layer() {
-                    Some(_) => interaction::overlay_color(ui, state, spec.content, role)
-                        .or(Some(ui.color(role))),
-                    None => Some(ui.color(role)),
-                },
-                None => transparent_state_color(ui, state, spec.content),
-            };
-            (background, ui.color(spec.content))
+        // 禁用那一对颜色**只求值一次**：背景与描边用的是同一对值（早先调了两次）
+        let disabled = state
+            .is_disabled()
+            .then(|| interaction::disabled_button_colors(ui, spec.base));
+
+        let (background, text_color) = match disabled {
+            Some((container, content)) => {
+                // 透明容器在禁用态依然透明（官方只改内容透明度）
+                (spec.fill.map(|_| container), content)
+            }
+            None => {
+                // 有填充：状态层叠在**容器角色**上；透明容器：叠在表面色上（否则 hover 看不见）
+                let background = match spec.fill {
+                    Some(role) => match state.layer() {
+                        Some(_) => interaction::overlay_color(ui, state, spec.content, role)
+                            .or(Some(ui.color(role))),
+                        None => Some(ui.color(role)),
+                    },
+                    None => transparent_state_color(ui, state, spec.content),
+                };
+                (background, ui.color(spec.content))
+            }
         };
 
-        let border_color = if state.is_disabled() {
-            interaction::disabled_button_colors(ui, Role::Surface).0
-        } else {
-            spec.border
-                .map_or_else(|| ui.color(Role::OutlineVariant), |role| ui.color(role))
+        let border_color = match disabled {
+            Some((container, _content)) => container,
+            None => spec
+                .border
+                .map_or_else(|| ui.color(Role::OutlineVariant), |role| ui.color(role)),
         };
 
         button::Style {
diff --git a/crates/app-iced/src/components/buttons/fab.rs b/crates/app-iced/src/components/buttons/fab.rs
index 71d7878..158218f 100644
--- a/crates/app-iced/src/components/buttons/fab.rs
+++ b/crates/app-iced/src/components/buttons/fab.rs
@@ -35,7 +35,7 @@ use unlucky_design::typography::{TypeRole, TypeStyle, Weight};
 use crate::icons;
 use crate::theme::Ui;
 
-use super::super::interaction::{self, Interaction};
+use super::super::interaction::{self, Base, Interaction};
 use super::super::layout;
 
 /// 扩展态右侧内距（px）。规格卡只量到起始 28（`FabSize::pad_start_px`），右侧没有量；
@@ -97,7 +97,7 @@ pub fn fab<'a, M: Clone + 'a>(ui: &'a Ui, spec: Fab<'a, M>) -> Element<'a, M> {
     let ink = match forced {
         // 禁用：38% 的内容色叠在容器上（与按钮族的容器档同一口径）
         Some(Interaction::Disabled) => {
-            interaction::disabled_button_content(ui, Role::OnPrimaryContainer, true)
+            interaction::disabled_button_content(ui, Base::CANVAS, Role::OnPrimaryContainer, true)
         }
         _ => ui.color(Role::OnPrimaryContainer),
     };
@@ -160,7 +160,7 @@ pub fn fab<'a, M: Clone + 'a>(ui: &'a Ui, spec: Fab<'a, M>) -> Element<'a, M> {
             None => Some(ui.color(Role::PrimaryContainer)),
         };
         let text_color = if state.is_disabled() {
-            interaction::disabled_button_content(ui, Role::OnPrimaryContainer, true)
+            interaction::disabled_button_content(ui, Base::CANVAS, Role::OnPrimaryContainer, true)
         } else {
             ui.color(Role::OnPrimaryContainer)
         };
diff --git a/crates/app-iced/src/components/buttons/icon_variant.rs b/crates/app-iced/src/components/buttons/icon_variant.rs
new file mode 100644
index 0000000..3caa0fa
--- /dev/null
+++ b/crates/app-iced/src/components/buttons/icon_variant.rs
@@ -0,0 +1,68 @@
+//! IconButton 的四式（规格卡 `ICON BUTTONS / FILLED - TONAL - OUTLINED - PLAIN`）。
+//!
+//! M234 纯搬移：本文件原来只是 `buttons/mod.rs` 的第 166~225 行（`mod.rs` 已顶到 399 行，
+//! 加 `.base(..)` 与 `icon_on` 之前必须先腾地方）。搬移**零行为改动**，`IconVariant` 的文档、
+//! 角色表、A1 出处一字未改；对外路径由 `mod.rs` 的 `pub use` 保持为 `buttons::IconVariant`。
+
+use unlucky_design::color::Role;
+
+/// IconButton 的**四式**（规格卡 `ICON BUTTONS / FILLED - TONAL - OUTLINED - PLAIN`）。
+///
+/// 规格卡画了四颗：实心 / 色调 / 描边 / 纯图标。12b §2.5 只有前三式（Standard / Filled / Tonal），
+/// M229 按规格卡把 Standard 拆成 **Plain**（纯图标）与 **Outlined**（1px 描边圆圈），
+/// `Standard` 这个名字保留为 `Plain` 的别名语义，避免既有调用点全改。
+#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
+pub enum IconVariant {
+    /// 纯图标（规格卡 `PLAIN`）：容器透明、图标 `OnSurfaceVariant`（各态图标色不变，12b 2.4）。
+    Plain,
+    /// 实心：`Primary` + `OnPrimary`。
+    Filled,
+    /// Tonal：`SecondaryContainer` + `OnSecondaryContainer`。
+    Tonal,
+    /// 描边：透明容器 + 1px `Outline`（规格卡第三颗，M229 新增）。
+    Outlined,
+}
+
+impl IconVariant {
+    /// 旧名字的别名：`Standard` = [`IconVariant::Plain`]（既有调用点不必改语义）。
+    #[allow(non_upper_case_globals)]
+    pub const Standard: IconVariant = IconVariant::Plain;
+
+    /// 四式全序（gallery 顺序 = 规格卡从左到右）。
+    pub const ALL: [IconVariant; 4] = [
+        IconVariant::Filled,
+        IconVariant::Tonal,
+        IconVariant::Outlined,
+        IconVariant::Plain,
+    ];
+
+    /// 稳定名字。
+    pub const fn name(self) -> &'static str {
+        match self {
+            IconVariant::Plain => "plain",
+            IconVariant::Filled => "filled",
+            IconVariant::Tonal => "tonal",
+            IconVariant::Outlined => "outlined",
+        }
+    }
+
+    /// **禁用态图标色**：四式都是 `OnSurface` @0.38 —— A1
+    /// （`StandardIconButtonTokens.DisabledColor` / `FilledIconButtonTokens.DisabledColor`）。
+    pub(crate) const fn disabled_content(self) -> Role {
+        Role::OnSurface
+    }
+
+    /// 色彩角色三元组（同 [`Variant::roles`] 的口径）。
+    pub(crate) const fn roles(self) -> (Option<Role>, Role, Option<Role>) {
+        match self {
+            IconVariant::Plain => (None, Role::OnSurfaceVariant, None),
+            IconVariant::Filled => (Some(Role::Primary), Role::OnPrimary, None),
+            IconVariant::Tonal => (
+                Some(Role::SecondaryContainer),
+                Role::OnSecondaryContainer,
+                None,
+            ),
+            IconVariant::Outlined => (None, Role::OnSurfaceVariant, Some(Role::Outline)),
+        }
+    }
+}
diff --git a/crates/app-iced/src/components/buttons/mod.rs b/crates/app-iced/src/components/buttons/mod.rs
index e098477..e621322 100644
--- a/crates/app-iced/src/components/buttons/mod.rs
+++ b/crates/app-iced/src/components/buttons/mod.rs
@@ -53,15 +53,17 @@ use unlucky_design::shape::ShapeScale;
 use crate::icons;
 use crate::theme::Ui;
 
-use super::interaction::Interaction;
+use super::interaction::{Base, Interaction};
 use super::layout;
 
 mod assemble;
 mod fab;
 mod geometry;
+mod icon_variant;
 
 pub use fab::{fab, Fab};
 pub use geometry::{Geometry, IconGeometry};
+pub use icon_variant::IconVariant;
 
 use assemble::{assemble, style_closure, StyleSpec};
 
@@ -163,67 +165,6 @@ impl Variant {
     }
 }
 
-/// IconButton 的**四式**（规格卡 `ICON BUTTONS / FILLED - TONAL - OUTLINED - PLAIN`）。
-///
-/// 规格卡画了四颗：实心 / 色调 / 描边 / 纯图标。12b §2.5 只有前三式（Standard / Filled / Tonal），
-/// M229 按规格卡把 Standard 拆成 **Plain**（纯图标）与 **Outlined**（1px 描边圆圈），
-/// `Standard` 这个名字保留为 `Plain` 的别名语义，避免既有调用点全改。
-#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
-pub enum IconVariant {
-    /// 纯图标（规格卡 `PLAIN`）：容器透明、图标 `OnSurfaceVariant`（各态图标色不变，12b 2.4）。
-    Plain,
-    /// 实心：`Primary` + `OnPrimary`。
-    Filled,
-    /// Tonal：`SecondaryContainer` + `OnSecondaryContainer`。
-    Tonal,
-    /// 描边：透明容器 + 1px `Outline`（规格卡第三颗，M229 新增）。
-    Outlined,
-}
-
-impl IconVariant {
-    /// 旧名字的别名：`Standard` = [`IconVariant::Plain`]（既有调用点不必改语义）。
-    #[allow(non_upper_case_globals)]
-    pub const Standard: IconVariant = IconVariant::Plain;
-
-    /// 四式全序（gallery 顺序 = 规格卡从左到右）。
-    pub const ALL: [IconVariant; 4] = [
-        IconVariant::Filled,
-        IconVariant::Tonal,
-        IconVariant::Outlined,
-        IconVariant::Plain,
-    ];
-
-    /// 稳定名字。
-    pub const fn name(self) -> &'static str {
-        match self {
-            IconVariant::Plain => "plain",
-            IconVariant::Filled => "filled",
-            IconVariant::Tonal => "tonal",
-            IconVariant::Outlined => "outlined",
-        }
-    }
-
-    /// **禁用态图标色**：四式都是 `OnSurface` @0.38 —— A1
-    /// （`StandardIconButtonTokens.DisabledColor` / `FilledIconButtonTokens.DisabledColor`）。
-    pub(crate) const fn disabled_content(self) -> Role {
-        Role::OnSurface
-    }
-
-    /// 色彩角色三元组（同 [`Variant::roles`] 的口径）。
-    pub(crate) const fn roles(self) -> (Option<Role>, Role, Option<Role>) {
-        match self {
-            IconVariant::Plain => (None, Role::OnSurfaceVariant, None),
-            IconVariant::Filled => (Some(Role::Primary), Role::OnPrimary, None),
-            IconVariant::Tonal => (
-                Some(Role::SecondaryContainer),
-                Role::OnSecondaryContainer,
-                None,
-            ),
-            IconVariant::Outlined => (None, Role::OnSurfaceVariant, Some(Role::Outline)),
-        }
-    }
-}
-
 /// 一个按钮的装配描述（五式共用；**不持有任何状态所有权**）。
 ///
 /// `on_press: Option<M>` 就是 M3 的 enabled/disabled 开关——`None` = 禁用，
@@ -238,6 +179,8 @@ pub struct Button<'a, M> {
     state: Option<Interaction>,
     /// 尺寸档（规格卡 `BUTTONS / XS - XL`）。产品默认 **S（40 高）**，与 M3 `control_height` 同值。
     size: ControlSize,
+    /// **脚下那一层的底**（M234）：禁用态的 10% 容器与 38% 内容叠在它上面。
+    base: Base,
 }
 
 impl<'a, M> Button<'a, M> {
@@ -250,6 +193,7 @@ impl<'a, M> Button<'a, M> {
             trailing: None,
             state: None,
             size: ControlSize::S,
+            base: Base::CANVAS,
         }
     }
 
@@ -262,6 +206,7 @@ impl<'a, M> Button<'a, M> {
             trailing: None,
             state: None,
             size: ControlSize::S,
+            base: Base::CANVAS,
         }
     }
 
@@ -291,6 +236,28 @@ impl<'a, M> Button<'a, M> {
         self.state = Some(state);
         self
     }
+
+    /// **告诉按钮它现在踩在什么底上**（M234）：禁用态的 10% 容器与 38% 内容都叠在这个底上。
+    ///
+    /// 放进卡片/面板/浮层里**必须**给——不给就按 [`Base::CANVAS`] 合成，禁用态会与容器底
+    /// 脱节（M223 的「CR 1.05、形丢失」）。容器自己的 `BASE` 常量就是标准答案：
+    /// 卡片 = [`super::surfaces::elevated::BASE`]、菜单项 = `super::inputs::menu::PANEL_BASE`。
+    ///
+    /// iced 没有环境上下文（样式闭包只拿得到 `&Theme`），所以这条信息只能显式传：
+    /// 这是「组件不猜宿主」的代价，也是 M229 那条「参数在、全传死值」的修法。
+    pub fn base(mut self, base: impl Into<Base>) -> Self {
+        self.base = base.into();
+        self
+    }
+
+    /// 视觉态：强制的先，否则「没有消息就是禁用」。
+    pub(super) fn forced(&self) -> Option<Interaction> {
+        self.state.or(if self.on_press.is_none() {
+            Some(Interaction::Disabled)
+        } else {
+            None
+        })
+    }
 }
 
 /// Filled 按钮（实心 `Primary`）。
@@ -337,6 +304,7 @@ pub(crate) fn icon_style_spec(
     variant: IconVariant,
     side: f32,
     forced: Option<Interaction>,
+    base: Base,
 ) -> StyleSpec {
     let (fill, content, border) = variant.roles();
     StyleSpec {
@@ -348,6 +316,7 @@ pub(crate) fn icon_style_spec(
         // M229 复审 P1-1：这里曾硬编码 `0.0`，于是 `Outlined` 与 `Plain` 逐像素相同。
         stroke: icon_stroke(variant),
         radius_side: side,
+        base,
         forced,
     }
 }
@@ -360,6 +329,8 @@ pub(crate) fn icon_style_spec(
 /// gallery 的样例因此统一用描边图标（`Download` + `ChevronRight`），并有单测钉住。
 ///
 /// `on_press: Option<M>`（`None` = 禁用）与 `state` 分开给：前者是语义，后者是取证开关。
+///
+/// 这是 **画布版**（禁用底 = [`Base::CANVAS`]）：放进卡片/面板里请用 [`icon_on`] 给真实父底。
 pub fn icon<'a, M: Clone + 'a>(
     ui: &'a Ui,
     variant: IconVariant,
@@ -367,6 +338,20 @@ pub fn icon<'a, M: Clone + 'a>(
     on_press: Option<M>,
     state: Option<Interaction>,
 ) -> Element<'a, M> {
+    icon_on(ui, variant, kind, on_press, state, Base::CANVAS)
+}
+
+/// 带**父底**的 IconButton（M234）：禁用态的 10% 容器与 38% 内容叠在 `base` 上。
+#[allow(clippy::too_many_arguments)]
+pub fn icon_on<'a, M: Clone + 'a>(
+    ui: &'a Ui,
+    variant: IconVariant,
+    kind: IconKind,
+    on_press: Option<M>,
+    state: Option<Interaction>,
+    base: impl Into<Base>,
+) -> Element<'a, M> {
+    let base = base.into();
     let geometry = IconGeometry::of(ui);
     let (fill, content, _) = variant.roles();
     let forced = state.or(if on_press.is_some() {
@@ -380,11 +365,12 @@ pub fn icon<'a, M: Clone + 'a>(
     // 这里把盒子做成整个 40×40（而不是 24×24）：`button::layout` 把内容放左上角、不居中，
     // 所以「居中」这件事必须由容器自己写死，别指望 button。
     // 内容色跟态走（禁用 = on-surface@38%），见 `assemble::content_color` 的说明
-    let glyph = assemble::content_color(ui, forced, content, fill, variant.disabled_content());
+    let glyph =
+        assemble::content_color(ui, base, forced, content, fill, variant.disabled_content());
     let icon_box =
         layout::centered_fixed(geometry.side, geometry.side, icons::view::<M>(kind, glyph));
 
-    let style = style_closure(ui, icon_style_spec(variant, geometry.side, forced));
+    let style = style_closure(ui, icon_style_spec(variant, geometry.side, forced, base));
 
     let element = button(icon_box)
         .width(Length::Fixed(geometry.side))
diff --git a/crates/app-iced/src/components/buttons/tests.rs b/crates/app-iced/src/components/buttons/tests.rs
index 82bc8f6..505608f 100644
--- a/crates/app-iced/src/components/buttons/tests.rs
+++ b/crates/app-iced/src/components/buttons/tests.rs
@@ -11,7 +11,7 @@ use unlucky_design::elevation::Elevation;
 use unlucky_design::icons::IconKind;
 use unlucky_design::spacing::Space;
 
-use super::super::interaction::{self, Interaction};
+use super::super::interaction::{self, Base, Interaction};
 use super::assemble::StyleSpec;
 use super::{style_closure, Geometry, IconGeometry, IconVariant, Variant};
 use crate::theme::{Families, Ui, STROKE_PX};
@@ -122,6 +122,7 @@ fn icon_button_geometry_matches_the_reference() {
     );
 }
 
+mod base;
 mod icon;
 
 /// 视觉 reviewer P2-3：同一控件里不许混用填充字形与描边字形（线宽语汇会打架）。
@@ -255,6 +256,7 @@ fn spec_of(variant: Variant, forced: Option<Interaction>) -> StyleSpec {
         content,
         border,
         shape: variant.shape(),
+        base: Base::CANVAS,
         stroke: Geometry::of(&light(), variant, false).stroke,
         radius_side: Geometry::of(&light(), variant, false).height,
         forced,
@@ -283,8 +285,7 @@ fn outlined_style_draws_hairline_border_and_full_radius() {
     assert_ne!(hovered.background, idle.background);
 
     let disabled = style(&ui.theme(), button::Status::Disabled);
-    let (container, content) =
-        interaction::disabled_button_colors(&ui, unlucky_design::color::Role::Surface);
+    let (container, content) = interaction::disabled_button_colors(&ui, Base::CANVAS);
     assert_eq!(disabled.text_color, content, "禁用内容 = 令牌 38%");
     assert_eq!(
         disabled.border.color, container,
diff --git a/crates/app-iced/src/components/buttons/tests/base.rs b/crates/app-iced/src/components/buttons/tests/base.rs
new file mode 100644
index 0000000..85edbfa
--- /dev/null
+++ b/crates/app-iced/src/components/buttons/tests/base.rs
@@ -0,0 +1,75 @@
+//! 禁用态**合成底**的接线判据（M234；从 `buttons/tests.rs` 拆出，守 400 行硬线）。
+//!
+//! 判据走真装配路径（`Button::base` → `text_style_spec` → `style_closure`），
+//! 不是「自己拼一个 `StyleSpec` 再喂进去」——后者证明不了接线（M229 复审 P1-1 的教训）。
+
+use iced::widget::button;
+use iced::Background;
+
+use unlucky_design::color::Role;
+use unlucky_design::color::SchemeFlavor;
+
+use super::super::Button;
+use super::{light, style_closure, Variant};
+use crate::app::components::interaction::Base;
+use crate::app::components::surfaces;
+use crate::theme::to_iced;
+
+/// **M234 的接线判据**：禁用按钮的容器色必须在**它被告诉的那层底**上合成。
+///
+/// 走的是**真装配路径**：`Button::base(..)` → `text_style_spec`（接线）→ `style_closure`
+/// （求值）。所以这条红了只有两种原因：① `assemble` 没把 `spec.base` 传下去；
+/// ② `disabled_button_colors` 内部又写死了画布色。
+///
+/// 抓得住：卡片/面板里的禁用按钮叠错底（M223 的「CR 1.05、形丢失」就是这么来的）。
+/// 抓不住：调用点**忘了**调 `.base(..)`（编译期不报错，默认 `Base::CANVAS`）——那一半由
+/// `gallery` 的像素 probe（`ULL_GALLERY_SECTION=disabledbase`）与卡片场景守。
+#[test]
+fn a_disabled_button_composites_over_the_base_it_is_given() {
+    use unlucky_design::color::BrandBoard;
+
+    let ui = light();
+    let card = surfaces::elevated::BASE;
+
+    let spec = super::super::assemble::text_style_spec(
+        &ui,
+        Variant::Filled,
+        &Button::<u8>::disabled("卡片里"),
+    );
+    assert_eq!(
+        spec.base,
+        Base::CANVAS,
+        "不调 `.base(..)` 时是画布底（默认值，语义写在 `Base::CANVAS` 的文档里）"
+    );
+
+    let card_spec = super::super::assemble::text_style_spec(
+        &ui,
+        Variant::Filled,
+        &Button::<u8>::disabled("卡片里").base(card),
+    );
+    assert_eq!(
+        card_spec.base, card,
+        "接线：`Button::base` 必须原样进 `StyleSpec`"
+    );
+
+    let card_style = style_closure(&ui, card_spec)(&ui.theme(), button::Status::Disabled);
+    let canvas_style = style_closure(&ui, spec)(&ui.theme(), button::Status::Disabled);
+
+    // 期望值独立算（写死 0.10 + 直接取色板角色），不调被测入口。
+    let scheme = BrandBoard::for_flavor(SchemeFlavor::Light).scheme();
+    let expected_card = to_iced(
+        scheme
+            .get(Role::OnSurface)
+            .with_alpha(0.10)
+            .over(scheme.get(Role::SurfaceContainer)),
+    );
+    assert_eq!(
+        card_style.background,
+        Some(Background::Color(expected_card)),
+        "卡片里的禁用 Filled 按钮容器 = on-surface@10% 叠 **SurfaceContainer**"
+    );
+    assert_ne!(
+        card_style.background, canvas_style.background,
+        "卡片底与画布底的合成结果必须不同（叠在画布上就是 M234 要修的那条）"
+    );
+}
diff --git a/crates/app-iced/src/components/buttons/tests/icon.rs b/crates/app-iced/src/components/buttons/tests/icon.rs
index cc359d6..f378dc5 100644
--- a/crates/app-iced/src/components/buttons/tests/icon.rs
+++ b/crates/app-iced/src/components/buttons/tests/icon.rs
@@ -38,7 +38,7 @@ fn only_the_outlined_icon_variant_draws_a_ring() {
         );
         // **接线断言**：`icon()` 真正塞进 `style_closure` 的那个结构体（`icon_style_spec`）。
         // 只测 `icon_stroke()` 抓不住「调用点写死 0」——第一版就是这样漏的（变异测试证明过）。
-        let spec = icon_style_spec(variant, 40.0, None);
+        let spec = icon_style_spec(variant, 40.0, None, Base::CANVAS);
         assert_eq!(
             spec.stroke,
             icon_stroke(variant),
diff --git a/crates/app-iced/src/components/feedback/action.rs b/crates/app-iced/src/components/feedback/action.rs
index 4b6d2d6..07a0090 100644
--- a/crates/app-iced/src/components/feedback/action.rs
+++ b/crates/app-iced/src/components/feedback/action.rs
@@ -20,7 +20,6 @@
 use iced::widget::{button, text};
 use iced::{Background, Border, Element, Length, Padding, Shadow};
 
-use unlucky_design::color::state::DISABLED_CONTENT_ALPHA;
 use unlucky_design::color::Role;
 use unlucky_design::component_map::Component;
 use unlucky_design::icons::IconKind;
@@ -28,7 +27,7 @@ use unlucky_design::spacing::Space;
 use unlucky_design::typography::TypeRole;
 
 use crate::icons;
-use crate::theme::{to_iced, Ui};
+use crate::theme::Ui;
 
 use super::super::interaction::{self, Interaction};
 use super::super::layout;
@@ -43,13 +42,14 @@ fn content_color(ui: &Ui, role: Role, container_role: Role, disabled: bool) -> i
     if !disabled {
         return ui.color(role);
     }
-    // 取 `Ui` 的当前方案（品牌板 / 取色方案），不重算 baseline（复审 F1）。
-    let scheme = ui.scheme();
-    to_iced(
-        scheme
-            .get(Role::OnSurface)
-            .with_alpha(DISABLED_CONTENT_ALPHA)
-            .over(scheme.get(container_role)),
+    // M234：`disabled_content_over_role` 现在收**任意**底（`Base`），所以这里的本地合成可以删掉
+    // ——底就是这两个动作件自己的容器角色（Snackbar = InverseSurface / Dialog = SurfaceContainerHigh），
+    // α 与叠法仍由 `interaction::disabled` 那一处给（本文件零 α 字面量）。
+    interaction::disabled_content_over_role(
+        ui,
+        interaction::Base::of(container_role),
+        Role::OnSurface,
+        false,
     )
 }
 
diff --git a/crates/app-iced/src/components/feedback/tests.rs b/crates/app-iced/src/components/feedback/tests.rs
index ae1f84a..6e3b635 100644
--- a/crates/app-iced/src/components/feedback/tests.rs
+++ b/crates/app-iced/src/components/feedback/tests.rs
@@ -11,7 +11,7 @@ use unlucky_design::typography::Platform;
 
 use crate::theme::{to_iced, Families, Ui};
 
-use super::super::interaction::{self, Interaction};
+use super::super::interaction::{self, Base, Interaction};
 use super::dialog::scrim;
 use super::panel::{DialogGeometry, EmptyStateGeometry, SnackbarGeometry};
 use super::progress::Progress;
@@ -235,7 +235,8 @@ fn snackbar_state_layers_come_from_the_interaction_module() {
     );
 
     // 禁用内容走 token 口径（38%），不是「变灰一点」
-    let disabled = interaction::disabled_content_over_role(&ui, Role::OnSurface, false);
+    let disabled =
+        interaction::disabled_content_over_role(&ui, Base::CANVAS, Role::OnSurface, false);
     assert_ne!(disabled, ui.color(Role::OnSurface));
     assert_eq!(disabled.a, 1.0);
 }
diff --git a/crates/app-iced/src/components/gallery/disabledbase.rs b/crates/app-iced/src/components/gallery/disabledbase.rs
new file mode 100644
index 0000000..f02d178
--- /dev/null
+++ b/crates/app-iced/src/components/gallery/disabledbase.rs
@@ -0,0 +1,212 @@
+//! 禁用态的**合成底**（M234）：同一批禁用控件摆在三种底上，一眼看出「叠的是哪一层」。
+//!
+//! ## 这张图回答什么
+//!
+//! M223 记的「CR 1.05、形丢失」是这么来的：`disabled.rs` 的入口收一个 `Role` 当合成底，
+//! 而**所有调用点都传死 `Role::Surface`**——卡片（`SurfaceContainer`）与面板
+//! （`SurfaceContainerLow`）里的禁用控件于是把 10%（按钮族）/ 12%（面状控件族）那一层叠在
+//! **画布色**上，与它真正的底差一层。
+//!
+//! 这里把三列**并排**摆出来，每列一块板、板底就是控件真踩的那层底：
+//!
+//! ```text
+//!   canvas    Surface                ← 页面底色
+//!   card      SurfaceContainer       ← `surfaces::elevated::card` 的底（`elevated::BASE`）
+//!   panel     SurfaceContainerLow    ← Card 层（取景板 / 面板）
+//! ```
+//!
+//! 每列都是**同一族控件**：Filled/Outlined 禁用按钮、Filled 禁用字段、禁用开关与 chip、
+//! 禁用搜索条、禁用列表项、禁用滑块、禁用 tab。控件拿的都是这一列的 [`Base`]，
+//! 所以列与列之间的差别只有「底」。
+//!
+//! ## 判据（数值在 `probe/base.rs`）
+//!
+//! 像素判据判的是**精确值**：卡列里的禁用按钮容器必须等于 `on-surface@10% 叠卡片底`，
+//! 且**不等于**画布底那一档。注意量级：Ink/Silver 板上 `Surface` 与 `SurfaceContainer`
+//! 只差个位数 RGB，10% 之后差 **≈1/255**——肉眼看不出来，所以这张图的用处是**取证**，
+//! 不是「看出区别」。真判据在 `interaction::disabled::tests`（逐值）与 `probe/base.rs`（像素）。
+//!
+//! ```text
+//! ULL_GALLERY_SECTION=disabledbase $EXE --software-renderer --screen=gallery \
+//!   --screenshot out.png --screenshot-theme=light
+//! ULL_GALLERY_SECTION=disabledbase ULL_GALLERY_SHOT=out.png \
+//!   cargo test -p unlucky-app-iced gallery::probe
+//! ```
+
+use iced::widget::{column, container, row, text};
+use iced::{Background, Border, Element, Length, Padding};
+
+use unlucky_design::color::Role;
+use unlucky_design::spacing::Space;
+use unlucky_design::typography::TypeRole;
+
+use crate::theme::Ui;
+
+use super::super::buttons::{self, Button};
+use super::super::inputs::{self, Field, SearchBar, Slider};
+use super::super::interaction::{self, Base, Interaction};
+use super::super::navigation::{self, ListItem, Tab, Tabs};
+use super::super::selection::{self, CheckValue, Checkbox, Chip, Radio, Switch};
+use super::{heading, DemoMessage};
+
+/// 一列的底（**板画什么，控件就叠什么**）。
+const COLUMNS: [(&str, Base); 3] = [
+    ("canvas · Surface", Base::CANVAS),
+    (
+        "card · SurfaceContainer",
+        super::super::surfaces::elevated::BASE,
+    ),
+    (
+        "panel · SurfaceContainerLow",
+        Base::of(Role::SurfaceContainerLow),
+    ),
+];
+
+/// 板宽：3 × 360 + 2 × 8 间距 = 1096 < 1180 − 2×24 页边距。
+const PLATE_WIDTH: f32 = 360.0;
+
+/// `#RRGGBB`（图上的色值要能直接和 probe 的期望值对上）。
+fn hex(color: iced::Color) -> String {
+    let channel = |v: f32| (v * 255.0).round() as u8;
+    format!(
+        "#{:02X}{:02X}{:02X}",
+        channel(color.r),
+        channel(color.g),
+        channel(color.b)
+    )
+}
+
+/// 整段（标题 + 三块并排的板）。
+pub(super) fn section<'a>(ui: &'a Ui) -> Element<'a, DemoMessage> {
+    let note = ui.style(TypeRole::BodySmall);
+    let columns = COLUMNS
+        .iter()
+        .copied()
+        .map(|(title, base)| plate(ui, title, base))
+        .collect::<Vec<_>>();
+
+    column![
+        heading(
+            ui,
+            "disabled · 合成底 = 所在容器的底（M234）",
+            "10%（按钮族）/ 12%（面状控件族）/ 38%（内容）全部预合成成实色；\
+             三列控件相同，只有**脚下的底**不同",
+        ),
+        row(columns).spacing(ui.space(Space::X2)),
+        text(
+            "三列的控件完全相同，只有脚下的底不同。禁用容器保留 90% 的底差（10% 只叠 on-surface），
+             所以列间的差别 = 底差的九成（浅色 Silver 底差 11/255、深色 Ink 底差 6/255）。
+             这张图是取证；判据在 `interaction::disabled::tests`（逐值）与 `gallery::probe` 的              disabledbase 段（精确像素）",
+        )
+        .size(note.size_px)
+        .font(ui.font_of(note))
+        .color(ui.color(Role::OnSurfaceVariant)),
+    ]
+    .spacing(ui.space(Space::X2))
+    .into()
+}
+
+/// 一块板：**底色就是这一列的 `base`**，控件全部把同一个 `base` 传进 `.base(..)`。
+///
+/// 板上写着这一列**算出来的**色值（同一入口：`disabled_button_colors` / `disabled_colors`）：
+/// 三列只差 ≈1/255，肉眼判不了，图上的数字是给 reviewer 与 probe 对账用的。
+fn plate<'a>(ui: &'a Ui, title: &'a str, base: Base) -> Element<'a, DemoMessage> {
+    let caption = ui.style(TypeRole::BodySmall);
+    let label = text(title)
+        .size(caption.size_px)
+        .font(ui.font_of(caption))
+        .color(ui.color(Role::OnSurface));
+    let numbers = text(format!(
+        "底 {} · 禁用按钮(10%) {} · 禁用字段(12%) {}",
+        hex(ui.color(base.role())),
+        hex(interaction::disabled_button_colors(ui, base).0),
+        hex(interaction::disabled_colors(ui, base).0),
+    ))
+    .size(caption.size_px)
+    .font(ui.font_of(caption))
+    .color(ui.color(Role::OnSurfaceVariant));
+
+    container(
+        column![
+            column![label, numbers].spacing(ui.space(Space::X1)),
+            column_body(ui, base)
+        ]
+        .spacing(ui.space(Space::X2)),
+    )
+    .width(Length::Fixed(PLATE_WIDTH))
+    .padding(Padding::from(ui.space(Space::X2)))
+    .style(move |_theme| container::Style {
+        // 板底 = 这一列的 base；描边只为让 `canvas` 列也有边界（画布色与页面同色）。
+        background: Some(Background::Color(ui.color(base.role()))),
+        border: Border {
+            color: ui.color(Role::OutlineVariant),
+            width: crate::theme::STROKE_PX,
+            radius: ui.radius_dp(unlucky_design::shape::ShapeScale::Medium),
+        },
+        ..container::Style::default()
+    })
+    .into()
+}
+
+/// 一列控件：**同族不同底**，每条都显式传 `base`。
+fn column_body<'a>(ui: &'a Ui, base: Base) -> Element<'a, DemoMessage> {
+    let gap = ui.space(Space::X2);
+    column![
+        row![
+            buttons::filled(ui, Button::disabled("保存").base(base)),
+            buttons::outlined(ui, Button::disabled("取消").base(base)),
+        ]
+        .spacing(gap),
+        inputs::text_field(
+            ui,
+            Field::new("")
+                .label("名称")
+                .placeholder("禁用字段")
+                .state(Interaction::Disabled)
+                .base(base),
+            |_| DemoMessage::Pressed("field"),
+        ),
+        row![
+            selection::checkbox(
+                ui,
+                Checkbox::disabled("勾选", CheckValue::Unchecked).base(base),
+            ),
+            selection::radio(ui, Radio::disabled("单选", false).base(base)),
+            selection::switch(ui, Switch::disabled("开关", false).base(base)),
+            selection::chip(
+                ui,
+                Chip::filter("标签", false, DemoMessage::Pressed("chip"))
+                    .disabled()
+                    .base(base),
+            ),
+        ]
+        .spacing(gap),
+        inputs::search_bar(
+            ui,
+            SearchBar::new("")
+                .placeholder("搜索")
+                .state(Interaction::Disabled)
+                .base(base),
+            |_| DemoMessage::Pressed("search"),
+        ),
+        navigation::list_item(
+            ui,
+            ListItem::new("列表项", DemoMessage::Pressed("item"))
+                .disabled()
+                .base(base),
+        ),
+        inputs::slider(
+            Slider::new(ui, 0.45)
+                .state(Interaction::Disabled)
+                .base(base),
+        ),
+        navigation::tabs(
+            ui,
+            Tabs::primary()
+                .tab(Tab::new("标签页", DemoMessage::Pressed("tab")).state(Interaction::Disabled),)
+                .base(base),
+        ),
+    ]
+    .spacing(gap)
+    .into()
+}
diff --git a/crates/app-iced/src/components/gallery/mod.rs b/crates/app-iced/src/components/gallery/mod.rs
index 5b5cec3..7a8ac2f 100644
--- a/crates/app-iced/src/components/gallery/mod.rs
+++ b/crates/app-iced/src/components/gallery/mod.rs
@@ -80,6 +80,7 @@ use super::interaction::Interaction;
 use super::layout;
 
 mod buttons;
+mod disabledbase;
 mod feedback;
 mod inputs;
 mod navigation;
@@ -97,6 +98,7 @@ pub const SECTION_ENV: &str = "ULL_GALLERY_SECTION";
 #[derive(Debug, Clone, Copy, PartialEq, Eq)]
 struct Sections {
     buttons: bool,
+    disabledbase: bool,
     sizes: bool,
     divider: bool,
     selection: bool,
@@ -109,6 +111,7 @@ impl Sections {
     /// 七段全渲染（默认）。
     const ALL: Self = Self {
         buttons: true,
+        disabledbase: true,
         sizes: true,
         divider: true,
         selection: true,
@@ -121,6 +124,7 @@ impl Sections {
     fn only(name: &str) -> Option<Self> {
         let mut sections = Self {
             buttons: false,
+            disabledbase: false,
             sizes: false,
             divider: false,
             selection: false,
@@ -130,6 +134,7 @@ impl Sections {
         };
         match name {
             "buttons" => sections.buttons = true,
+            "disabledbase" => sections.disabledbase = true,
             "sizes" => sections.sizes = true,
             "divider" => sections.divider = true,
             "selection" => sections.selection = true,
@@ -156,7 +161,7 @@ impl Sections {
             return sections;
         }
         eprintln!(
-            "[gallery] {SECTION_ENV}={raw:?} 不是已知段（all|buttons|sizes|divider|selection|inputs|feedback|navigation），已回落 all"
+            "[gallery] {SECTION_ENV}={raw:?} 不是已知段（all|buttons|disabledbase|sizes|divider|selection|inputs|feedback|navigation），已回落 all"
         );
         Self::ALL
     }
@@ -166,6 +171,7 @@ impl Sections {
         let mut names = Vec::new();
         for (on, name) in [
             (self.buttons, "buttons"),
+            (self.disabledbase, "disabledbase"),
             (self.sizes, "sizes"),
             (self.divider, "divider"),
             (self.selection, "selection"),
@@ -244,6 +250,9 @@ pub fn view<'a>(ui: &'a Ui) -> Element<'a, DemoMessage> {
     if picked.buttons {
         sections = sections.push(buttons::section(ui));
     }
+    if picked.disabledbase {
+        sections = sections.push(disabledbase::section(ui));
+    }
     if picked.sizes {
         sections = sections.push(sizes::section(ui));
     }
diff --git a/crates/app-iced/src/components/gallery/probe.rs b/crates/app-iced/src/components/gallery/probe.rs
index 2ade179..6543e7d 100644
--- a/crates/app-iced/src/components/gallery/probe.rs
+++ b/crates/app-iced/src/components/gallery/probe.rs
@@ -36,10 +36,11 @@ use unlucky_design::typography::Platform;
 
 use crate::theme::{Families, Ui};
 
-use crate::app::components::interaction;
+use crate::app::components::interaction::{self, Base};
 
 use super::scan::{matches, nearer, rgb, Shot};
 
+mod bases;
 mod rows;
 
 const FAMILIES: Families = Families {
@@ -146,14 +147,19 @@ fn gallery_geometry_matches_the_tokens() {
         .trim()
         .to_ascii_lowercase();
     assert!(
-        section == "buttons" || section == "divider",
-        "这份 probe 只支持 `ULL_GALLERY_SECTION=buttons`（按钮矩阵）或 `divider`（分隔线）；当前 {section:?}。`all` 不行：整页比视口高，分隔线段与按钮矩阵不可能同屏。"
+        section == "buttons" || section == "divider" || section == "disabledbase",
+        "这份 probe 只支持 `ULL_GALLERY_SECTION=buttons`（按钮矩阵）/ `divider`（分隔线）/ `disabledbase`（禁用态合成底）；当前 {section:?}。`all` 不行：整页比视口高，分隔线段与按钮矩阵不可能同屏。"
     );
     // 分隔线那段是**独立出口**：`divider` 段的 sheet 里没有按钮矩阵，判据也不同。
     if section == "divider" {
         check_divider(&shot, &ui);
         return;
     }
+    // 禁用态合成底（M234）：三块板各按自己的底合成，判据在 `probe/base.rs`。
+    if section == "disabledbase" {
+        bases::check(&shot, &ui, flavor);
+        return;
+    }
 
     // ---- 12b 1.1 / 1.2：实心按钮 40 高、药丸圆角 20 ------------------------------
     let primary = shot.bbox_of(rgb(ui.color(Role::Primary)));
@@ -309,7 +315,7 @@ fn gallery_geometry_matches_the_tokens() {
     //
     // **按钮族**：容器 10%（官方 `*ButtonTokens.DisabledContainerOpacity = 0.1f`）、内容 38%。
     // M86 之前这里和 chip 共用同一个 12% 常量，所以断言与实现「一起错」、永远同源——拆族后才对得上。
-    let (disabled_container, _) = interaction::disabled_button_colors(&ui, Role::Surface);
+    let (disabled_container, _) = interaction::disabled_button_colors(&ui, Base::CANVAS);
     assert!(
         shot.bbox_of(rgb(disabled_container))
             .iter()
diff --git a/crates/app-iced/src/components/gallery/probe/bases.rs b/crates/app-iced/src/components/gallery/probe/bases.rs
new file mode 100644
index 0000000..beb6490
--- /dev/null
+++ b/crates/app-iced/src/components/gallery/probe/bases.rs
@@ -0,0 +1,216 @@
+//! `ULL_GALLERY_SECTION=disabledbase` 的像素判据：**禁用态叠的是哪一层底**（M234）。
+//!
+//! ## 为什么必须用「精确匹配」而不是扫描工具的 `matches`（±10）
+//!
+//! Ink / Silver 板上 `Surface` 与 `SurfaceContainer` 只差个位数 RGB，10% 之后差 **≈1/255**：
+//! `scan::matches` 的 ±10 容差会把「叠在画布上」与「叠在卡片上」判成同一个颜色——
+//! 那样这条判据就永远绿。所以本文件自己数**逐位相等**的像素（[`count_exact`]），
+//! 并且只数**板内**区域，避开页面底色。
+//!
+//! ## 量什么
+//!
+//! 1. 卡列 / 面板列里：禁用按钮容器（按钮族 10%）与禁用字段容器（面状族 12%）的像素值
+//!    = 各自「@10%/12% 叠**该列板底**」；**不许**出现「叠画布底」那一档；
+//! 2. 画布列（卡列左侧、同样的纵向范围）里反过来：出现画布档、且不是卡/面板档；
+//! 3. 三档的期望值两两不同（哪一对相等，说明 `Base` 被丢了或两族 α 合流了）。
+//!
+//! ## 抓得住 / 抓不住
+//!
+//! - 抓得住：调用点把底传错（叠画布）或没传（默认 `Base::CANVAS`）——卡列里会出现画布档的像素
+//!   而缺卡片档；两族 α 合流、入口内部写死 `Role::Surface`，同样在这里红。
+//! - 抓不住：① 容器**自己**的画法（板底 vs 卡组件的 `BASE` 是否一致——那条由
+//!   `surfaces::elevated::tests` 的「卡底必须是 SurfaceContainer」守）；
+//!   ② 页面里的真实卡片（pages/ 的调用点尚未接 `.base(..)`，见报告「没验的部分」）；
+//!   ③ GPU(wgpu) 档：本判据读的是 tiny-skia(`--software-renderer`) 出的图；
+//!   ④ 差 <1/255 的第三层底（例如 `SurfaceContainer` 与 `SurfaceContainerHigh` 的 10%）——
+//!   那种情况本文件会退化成「两档相等」，第 3 条断言会红，**不会静默放过**。
+
+use unlucky_design::color::Role;
+
+use super::super::scan::{rgb, Shot};
+use crate::app::components::interaction::{self, Base};
+use crate::app::components::surfaces;
+use crate::theme::Ui;
+
+/// 板子的最小尺寸（判据只认「一整列」，不许把某个控件误当成板）。
+const MIN_PLATE_W: usize = 300;
+const MIN_PLATE_H: usize = 260;
+/// 禁用按钮容器在板内的最少像素（Filled 药丸 40 高 × ≥58 宽，扣掉字形与圆角）。
+const MIN_BUTTON_PX: usize = 300;
+/// 禁用字段容器的最少像素（板宽 ~336 × 56，扣掉标签与图标）。
+const MIN_FIELD_PX: usize = 3000;
+/// 「正确档位 : 错误档位」的最小倍数。
+///
+/// 为什么不干脆要求「错误档位 = 0 px」：**抗锯齿会造出中间色**——板底与控件容器之间那一圈
+/// 1px 过渡像素会顺路撞上「另一档」的精确值（实测卡片列里 226/226/227 有 58 px，全是边缘）。
+/// 真实回归的量级完全不同（整颗按钮 ≈3000 px、整块字段 ≈18000 px），所以判据写成**倍数**：
+/// 正确档位必须比错误档位多一个数量级。
+const STRAY_RATIO: usize = 10;
+
+/// 逐位相等的像素计数器（`scan::matches` 的 ±10 容差在这里不够用，见模块文档）。
+fn count_exact(shot: &Shot, color: [u8; 3], x0: usize, x1: usize, y0: usize, y1: usize) -> usize {
+    (y0..y1.min(shot.height))
+        .map(|y| {
+            (x0..x1.min(shot.width))
+                .filter(|x| shot.at(*x, y) == color)
+                .count()
+        })
+        .sum()
+}
+
+/// 一块板（`left..right × top..bottom`，闭区间；`x1`/`y1` 是开区间上界）。
+type Rect = (usize, usize, usize, usize);
+
+/// 按**逐位相等**的颜色切出竖列：每列 = 一段连续且够宽的 x，y 取该段内的最小/最大行。
+///
+/// 为什么不用 `scan::bbox_of`（±10 容差）：本板的三档底（`Surface` / `SurfaceContainer` /
+/// `SurfaceContainerLow`）两两只差 5~11 个 RGB 单位，落在容差里会被并成一块
+/// （实测把卡片列与面板列判成同一块）。
+fn exact_columns(shot: &Shot, color: [u8; 3]) -> Vec<Rect> {
+    let mut columns = Vec::new();
+    let mut current: Option<(usize, usize, usize, usize)> = None;
+    for x in 0..shot.width {
+        let rows: Vec<usize> = (0..shot.height)
+            .filter(|y| shot.at(x, *y) == color)
+            .collect();
+        match (&mut current, rows.first()) {
+            (None, Some(top)) => {
+                current = Some((x, x + 1, *top, rows[rows.len() - 1] + 1));
+            }
+            (Some(col), Some(top)) => {
+                col.1 = x + 1;
+                col.2 = col.2.min(*top);
+                col.3 = col.3.max(rows[rows.len() - 1] + 1);
+            }
+            (Some(col), None) => {
+                if col.1 - col.0 >= MIN_PLATE_W && col.3 - col.2 >= MIN_PLATE_H {
+                    columns.push(*col);
+                }
+                current = None;
+            }
+            (None, None) => {}
+        }
+    }
+    if let Some(col) = current {
+        if col.1 - col.0 >= MIN_PLATE_W && col.3 - col.2 >= MIN_PLATE_H {
+            columns.push(col);
+        }
+    }
+    columns
+}
+
+fn find_plate(shot: &Shot, role: Role, ui: &Ui, name: &str) -> Rect {
+    let color = rgb(ui.color(role));
+    let mut columns = exact_columns(shot, color);
+    assert_eq!(
+        columns.len(),
+        1,
+        "{name} 列（{role:?} 底，{color:?}）应当恰好是 1 列，实测 {}：         板子尺寸判据 MIN {MIN_PLATE_W}×{MIN_PLATE_H}",
+        columns.len()
+    );
+    columns.remove(0)
+}
+
+/// 判据入口（`probe.rs` 的 `disabledbase` 分支调它）。
+pub(super) fn check(shot: &Shot, ui: &Ui, flavor: unlucky_design::color::SchemeFlavor) {
+    let card = Base::of(Role::SurfaceContainer);
+    let panel = Base::of(Role::SurfaceContainerLow);
+
+    let card_rect = find_plate(shot, Role::SurfaceContainer, ui, "card");
+    let panel_rect = find_plate(shot, Role::SurfaceContainerLow, ui, "panel");
+    // 画布列：三列等宽等距（`disabledbase::PLATE_WIDTH` 固定 360、间距 8），所以它 =
+    // 卡列左侧同样宽的一列。画布板的底与页面同色（`Surface`），**没法**靠颜色切出来。
+    let step = panel_rect.0 - card_rect.0;
+    assert!(
+        step > MIN_PLATE_W,
+        "两列间距 {step} 不合理（列宽 {MIN_PLATE_W} 起）—— 布局变了，画布列的镜像推算不再成立"
+    );
+    let canvas_rect = (0, card_rect.0, card_rect.2, card_rect.3);
+    let canvas_left = card_rect.0.saturating_sub(step);
+
+    let button = |base: Base| rgb(interaction::disabled_button_colors(ui, base).0);
+    let field = |base: Base| rgb(interaction::disabled_colors(ui, base).0);
+
+    // 三档必须两两不同（哪一对相等就说明底被丢了 / 两族 α 合流了）
+    let (canvas_button, canvas_field) = (button(Base::CANVAS), field(Base::CANVAS));
+    let (card_button, card_field) = (button(card), field(card));
+    let (panel_button, panel_field) = (button(panel), field(panel));
+    assert_ne!(
+        canvas_button, card_button,
+        "{flavor:?}：画布底与卡片底算出来的按钮容器相同 —— 底被丢了"
+    );
+    assert_ne!(
+        canvas_field, card_field,
+        "{flavor:?}：画布底与卡片底算出来的字段容器相同"
+    );
+    assert_ne!(
+        card_button, panel_button,
+        "{flavor:?}：卡片底与面板底必须可分"
+    );
+    assert_ne!(
+        card_field, panel_field,
+        "{flavor:?}：卡片底与面板底必须可分"
+    );
+    assert_eq!(
+        surfaces::elevated::BASE,
+        card,
+        "卡片列用的底就该是 `surfaces::elevated::BASE`（容器导出的那个常量）"
+    );
+
+    for (rect, base, wanted_button, wanted_field, name) in [
+        (card_rect, card, card_button, card_field, "card"),
+        (panel_rect, panel, panel_button, panel_field, "panel"),
+    ] {
+        let (x0, x1, y0, y1) = rect;
+        let hits = count_exact(shot, wanted_button, x0, x1, y0, y1);
+        assert!(
+            hits >= MIN_BUTTON_PX,
+            "{name} 列里「叠 {:?}」的禁用按钮容器只有 {hits} px（应 ≥{MIN_BUTTON_PX}）：\
+             这一列的禁用控件没把真实父底传下去",
+            base.role()
+        );
+        let hits = count_exact(shot, wanted_field, x0, x1, y0, y1);
+        assert!(
+            hits >= MIN_FIELD_PX,
+            "{name} 列里「叠 {:?}」的禁用字段容器只有 {hits} px（应 ≥{MIN_FIELD_PX}）",
+            base.role()
+        );
+        // 反向：这一列里不许出现「叠画布底」的那一档
+        let stray = count_exact(shot, canvas_button, x0, x1, y0, y1);
+        assert!(
+            hits > stray * STRAY_RATIO,
+            "{name} 列里「叠 {:?}」的禁用按钮容器只有 {hits} px，而「叠画布」的有 {stray} px              （要求前者 ≥ 后者 ×{STRAY_RATIO}）—— 这一列的控件仍在按 Role::Surface 合成",
+            base.role()
+        );
+        let stray = count_exact(shot, canvas_field, x0, x1, y0, y1);
+        assert!(
+            hits > stray * STRAY_RATIO,
+            "{name} 列里「叠 {:?}」的禁用字段容器只有 {hits} px，而「叠画布」的有 {stray} px              （要求前者 ≥ 后者 ×{STRAY_RATIO}）",
+            base.role()
+        );
+        assert!(
+            base.role() != Role::Surface,
+            "{name} 列不该是画布底（判据自己写错了）"
+        );
+    }
+
+    // 画布列：反过来必须出现画布档
+    let (_, cx1, cy0, cy1) = canvas_rect;
+    let cx0 = canvas_left;
+    let canvas_hits = count_exact(shot, canvas_button, cx0, cx1, cy0, cy1);
+    assert!(
+        canvas_hits >= MIN_BUTTON_PX,
+        "画布列里没有「叠画布」的禁用按钮容器 —— 对照组不成立"
+    );
+    let canvas_card_hits = count_exact(shot, card_button, cx0, cx1, cy0, cy1);
+    assert!(
+        canvas_hits > canvas_card_hits * STRAY_RATIO,
+        "画布列里「叠画布」的禁用按钮容器 {canvas_hits} px，而「叠卡片底」的有 {canvas_card_hits} px          —— 画布列的控件被传了卡片底"
+    );
+
+    eprintln!(
+        "[probe] OK section=disabledbase flavor={flavor:?}：\
+         canvas 按钮 {:?} / 卡片 {} / 面板 {} ⇒ 三列各按自己的底合成",
+        canvas_button, card_rect.0, panel_rect.0
+    );
+}
diff --git a/crates/app-iced/src/components/gallery/probe/rows.rs b/crates/app-iced/src/components/gallery/probe/rows.rs
index dfd3b28..7472a14 100644
--- a/crates/app-iced/src/components/gallery/probe/rows.rs
+++ b/crates/app-iced/src/components/gallery/probe/rows.rs
@@ -7,6 +7,7 @@ use unlucky_design::color::Role;
 
 use super::super::scan::{rgb, Shot};
 use crate::app::components::interaction;
+use crate::app::components::interaction::Base;
 use crate::theme::Ui;
 
 /// 矩阵行距（40 高按钮 + 8 间距）。
@@ -38,7 +39,7 @@ pub(super) fn assert_matrix_rows(shot: &Shot, ui: &Ui, label_top: usize, label_l
         let y1 = y0 + ROW_HEIGHT;
         // **与实现同源**：按钮族的内容色一律走 `disabled_button_content`（38% 叠在 10% 底上）。
         // 用面状控件族的 12% 底会让断言比实现宽一档，差的 1/255 会放跑「容器对内容错」。
-        let ink = interaction::disabled_button_content(ui, role, on_container);
+        let ink = interaction::disabled_button_content(ui, Base::CANVAS, role, on_container);
         let count = shot.count_in(rgb(ink), column_from, shot.width, y0, y1);
         // 阈值 **30**：最窄的一行是只有 4 个字符的 `text` 变体（实测 38 px 墨迹，M229 复审后
         // 按钮内距 24→20 让标签左移，余量只剩 2 px）。角色接错时会掉到个位数甚至 0。
diff --git a/crates/app-iced/src/components/inputs/field.rs b/crates/app-iced/src/components/inputs/field.rs
index 32a0bad..d9602d6 100644
--- a/crates/app-iced/src/components/inputs/field.rs
+++ b/crates/app-iced/src/components/inputs/field.rs
@@ -22,7 +22,6 @@ use iced::widget::text::LineHeight;
 use iced::widget::{column, container, row, text, text_input};
 use iced::{Alignment, Background, Border, Color, Element, Length, Padding, Pixels};
 
-use unlucky_design::color::Role;
 use unlucky_design::icons::IconKind;
 use unlucky_design::spacing::Space;
 use unlucky_design::typography::TypeRole;
@@ -30,10 +29,16 @@ use unlucky_design::typography::TypeRole;
 use crate::icons;
 use crate::theme::Ui;
 
-use super::super::interaction::{self, Interaction};
+use super::super::interaction::{Base, Interaction};
+
+#[cfg(test)]
+use super::super::interaction;
 use super::super::layout;
 use super::geometry::FieldGeometry;
 
+mod paint;
+use paint::palette;
+
 /// 两式容器（12b 9.3 / 9.4 的差别：Filled 有容器色 + 底部指示线；Outlined 只有描边）。
 #[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
 pub enum FieldVariant {
@@ -70,6 +75,8 @@ pub struct Field<'a> {
     state: Option<Interaction>,
     width: Length,
     secure: bool,
+    /// 脚下那一层的底（M234，禁用态合成用）。
+    base: Base,
 }
 
 impl<'a> Field<'a> {
@@ -87,9 +94,19 @@ impl<'a> Field<'a> {
             state: None,
             width: Length::Fill,
             secure: false,
+            base: Base::CANVAS,
         }
     }
 
+    /// **告诉字段它踩在什么底上**（M234）：禁用态的 12% 容器 / 描边与 38% 内容都叠在这个底上。
+    ///
+    /// 放进卡片/面板里必须给（卡片 = `surfaces::elevated::BASE`）；不给就按画布合成，
+    /// 禁用字段会与容器底脱节（M223 的「形丢失」）。
+    pub fn base(mut self, base: impl Into<Base>) -> Self {
+        self.base = base.into();
+        self
+    }
+
     /// 选式（Filled / Outlined）。
     pub fn variant(mut self, variant: FieldVariant) -> Self {
         self.variant = variant;
@@ -151,106 +168,6 @@ impl<'a> Field<'a> {
     }
 }
 
-/// 一个字段在某一态下的全套颜色（9.4 / 9.7 / 9.8 的落点）。
-#[derive(Debug, Clone, Copy, PartialEq)]
-struct Palette {
-    /// 容器底色；`None` = 透明（Outlined）。
-    fill: Option<Color>,
-    /// 描边/指示线色。
-    line: Color,
-    /// 描边/指示线宽（1 或 2）。
-    stroke: f32,
-    /// 标签（`BodySmall`）。
-    label: Color,
-    /// 输入文本。
-    input: Color,
-    /// 前后图标。
-    icon: Color,
-    /// 辅助文本。
-    supporting: Color,
-    /// 占位文本。
-    placeholder: Color,
-}
-
-/// 解析某一态的颜色（**唯一**做角色映射的地方）。
-fn palette(ui: &Ui, variant: FieldVariant, state: Interaction, error: bool) -> Palette {
-    let geometry = FieldGeometry::of(ui, true, None);
-
-    if state.is_disabled() {
-        // 9.8：内容一律 OnSurface@38%；Filled 容器叠 12%（官方 4%，令牌无 4% 档 → D10）；
-        // Outlined 描边正好是官方 12%。
-        let container = interaction::disabled_colors(ui, Role::Surface).0;
-        let ink = interaction::disabled_content_over_role(
-            ui,
-            Role::OnSurface,
-            matches!(variant, FieldVariant::Filled),
-        );
-        return Palette {
-            fill: match variant {
-                FieldVariant::Filled => Some(container),
-                FieldVariant::Outlined => None,
-            },
-            line: match variant {
-                FieldVariant::Filled => ink,
-                FieldVariant::Outlined => container,
-            },
-            stroke: geometry.stroke,
-            label: ink,
-            input: ink,
-            icon: ink,
-            supporting: ink,
-            placeholder: ink,
-        };
-    }
-
-    let focused = matches!(state, Interaction::Focused);
-    let hovered = matches!(state, Interaction::Hovered | Interaction::Pressed);
-
-    let (line, stroke) = if error {
-        (ui.color(Role::Error), geometry.focus_stroke)
-    } else if focused {
-        (ui.color(Role::Primary), geometry.focus_stroke)
-    } else if hovered {
-        (ui.color(Role::OnSurface), geometry.stroke)
-    } else {
-        (
-            match variant {
-                FieldVariant::Filled => ui.color(Role::OnSurfaceVariant),
-                FieldVariant::Outlined => ui.color(Role::Outline),
-            },
-            geometry.stroke,
-        )
-    };
-
-    Palette {
-        fill: match variant {
-            FieldVariant::Filled => Some(ui.color(Role::SurfaceContainerHighest)),
-            FieldVariant::Outlined => None,
-        },
-        line,
-        stroke,
-        label: if error {
-            ui.color(Role::Error)
-        } else if focused {
-            ui.color(Role::Primary)
-        } else {
-            ui.color(Role::OnSurfaceVariant)
-        },
-        input: ui.color(Role::OnSurface),
-        icon: if error {
-            ui.color(Role::Error)
-        } else {
-            ui.color(Role::OnSurfaceVariant)
-        },
-        supporting: if error {
-            ui.color(Role::Error)
-        } else {
-            ui.color(Role::OnSurfaceVariant)
-        },
-        placeholder: ui.color(Role::OnSurfaceVariant),
-    }
-}
-
 /// 一个文本框（Filled / Outlined 由 [`Field::variant`] 选）。
 ///
 /// 受控：值由外部持有，输入经 `on_input` 回传；`state` 强制成 `Disabled` 时输入被摘掉
@@ -262,7 +179,7 @@ pub fn text_field<'a, M: Clone + 'a>(
 ) -> Element<'a, M> {
     let geometry = FieldGeometry::of(ui, field.label.is_some(), field.leading);
     let state = field.state.unwrap_or(Interaction::Enabled);
-    let colors = palette(ui, field.variant, state, field.error);
+    let colors = palette(ui, field.base, field.variant, state, field.error);
 
     let input_style = ui.style(TypeRole::BodyLarge);
     let label_style = ui.style(TypeRole::BodySmall);
diff --git a/crates/app-iced/src/components/inputs/field/paint.rs b/crates/app-iced/src/components/inputs/field/paint.rs
new file mode 100644
index 0000000..436d693
--- /dev/null
+++ b/crates/app-iced/src/components/inputs/field/paint.rs
@@ -0,0 +1,125 @@
+//! 文本框的颜色求值（`research/12b` §9.4 / §9.7 / §9.8 的落点）。
+//!
+//! M234 纯搬移：本文件原来是 `inputs/field.rs` 的 `Palette` + `palette()`（`field.rs` 已顶到
+//! 398 行，加 `.base(..)` 之前必须腾地方）。搬移只做了一件事以外的零改动——`palette()` 多收
+//! 一个 [`Base`]（禁用态的合成底，M234），其余角色映射一字未改。
+
+use iced::Color;
+
+use unlucky_design::color::Role;
+
+use crate::theme::Ui;
+
+use super::super::super::interaction::{self, Base, Interaction};
+use super::super::geometry::FieldGeometry;
+use super::FieldVariant;
+
+/// 一个字段在某一态下的全套颜色（9.4 / 9.7 / 9.8 的落点）。
+#[derive(Debug, Clone, Copy, PartialEq)]
+pub(super) struct Palette {
+    /// 容器底色；`None` = 透明（Outlined）。
+    pub(super) fill: Option<Color>,
+    /// 描边/指示线色。
+    pub(super) line: Color,
+    /// 描边/指示线宽（1 或 2）。
+    pub(super) stroke: f32,
+    /// 标签（`BodySmall`）。
+    pub(super) label: Color,
+    /// 输入文本。
+    pub(super) input: Color,
+    /// 前后图标。
+    pub(super) icon: Color,
+    /// 辅助文本。
+    pub(super) supporting: Color,
+    /// 占位文本。
+    pub(super) placeholder: Color,
+}
+
+/// 解析某一态的颜色（**唯一**做角色映射的地方）。
+///
+/// `base` 是字段**脚下那一层的底**（M234）：禁用态的 12% 容器与 38% 内容都叠在它上面
+/// （Filled 容器 / Outlined 描边 / 全部标签与文本）。调用点给真实父底，不写死 `Role::Surface`。
+pub(super) fn palette(
+    ui: &Ui,
+    base: Base,
+    variant: FieldVariant,
+    state: Interaction,
+    error: bool,
+) -> Palette {
+    let geometry = FieldGeometry::of(ui, true, None);
+
+    if state.is_disabled() {
+        // 9.8：内容一律 OnSurface@38%；Filled 容器叠 12%（官方 4%，令牌无 4% 档 → D10）；
+        // Outlined 描边正好是官方 12%。
+        let container = interaction::disabled_colors(ui, base).0;
+        let ink = interaction::disabled_content_over_role(
+            ui,
+            base,
+            Role::OnSurface,
+            matches!(variant, FieldVariant::Filled),
+        );
+        return Palette {
+            fill: match variant {
+                FieldVariant::Filled => Some(container),
+                FieldVariant::Outlined => None,
+            },
+            line: match variant {
+                FieldVariant::Filled => ink,
+                FieldVariant::Outlined => container,
+            },
+            stroke: geometry.stroke,
+            label: ink,
+            input: ink,
+            icon: ink,
+            supporting: ink,
+            placeholder: ink,
+        };
+    }
+
+    let focused = matches!(state, Interaction::Focused);
+    let hovered = matches!(state, Interaction::Hovered | Interaction::Pressed);
+
+    let (line, stroke) = if error {
+        (ui.color(Role::Error), geometry.focus_stroke)
+    } else if focused {
+        (ui.color(Role::Primary), geometry.focus_stroke)
+    } else if hovered {
+        (ui.color(Role::OnSurface), geometry.stroke)
+    } else {
+        (
+            match variant {
+                FieldVariant::Filled => ui.color(Role::OnSurfaceVariant),
+                FieldVariant::Outlined => ui.color(Role::Outline),
+            },
+            geometry.stroke,
+        )
+    };
+
+    Palette {
+        fill: match variant {
+            FieldVariant::Filled => Some(ui.color(Role::SurfaceContainerHighest)),
+            FieldVariant::Outlined => None,
+        },
+        line,
+        stroke,
+        label: if error {
+            ui.color(Role::Error)
+        } else if focused {
+            ui.color(Role::Primary)
+        } else {
+            ui.color(Role::OnSurfaceVariant)
+        },
+        input: ui.color(Role::OnSurface),
+        icon: if error {
+            ui.color(Role::Error)
+        } else {
+            ui.color(Role::OnSurfaceVariant)
+        },
+        supporting: if error {
+            ui.color(Role::Error)
+        } else {
+            ui.color(Role::OnSurfaceVariant)
+        },
+        placeholder: ui.color(Role::OnSurfaceVariant),
+    }
+}
diff --git a/crates/app-iced/src/components/inputs/field/tests.rs b/crates/app-iced/src/components/inputs/field/tests.rs
index f24e9ff..64302bd 100644
--- a/crates/app-iced/src/components/inputs/field/tests.rs
+++ b/crates/app-iced/src/components/inputs/field/tests.rs
@@ -1,6 +1,7 @@
 //! field 的单测（从 `field.rs` 拆出：单文件 ≤400 行，AGENTS.md §3-1）。
 
 use super::*;
+use unlucky_design::color::Role;
 use unlucky_design::color::SchemeFlavor;
 use unlucky_design::typography::Platform;
 
@@ -44,23 +45,47 @@ fn every_variant_and_state_builds() {
 #[test]
 fn outline_colors_and_widths_follow_the_state() {
     let ui = ui(SchemeFlavor::Light);
-    let rest = palette(&ui, FieldVariant::Outlined, Interaction::Enabled, false);
+    let rest = palette(
+        &ui,
+        Base::CANVAS,
+        FieldVariant::Outlined,
+        Interaction::Enabled,
+        false,
+    );
     assert_eq!(rest.line, ui.color(Role::Outline));
     assert_eq!(rest.stroke, 1.0);
     assert_eq!(rest.fill, None, "Outlined 无容器色");
 
-    let hover = palette(&ui, FieldVariant::Outlined, Interaction::Hovered, false);
+    let hover = palette(
+        &ui,
+        Base::CANVAS,
+        FieldVariant::Outlined,
+        Interaction::Hovered,
+        false,
+    );
     assert_eq!(hover.line, ui.color(Role::OnSurface));
     assert_eq!(hover.stroke, 1.0);
 
-    let focus = palette(&ui, FieldVariant::Outlined, Interaction::Focused, false);
+    let focus = palette(
+        &ui,
+        Base::CANVAS,
+        FieldVariant::Outlined,
+        Interaction::Focused,
+        false,
+    );
     assert_eq!(focus.line, ui.color(Role::Primary));
     assert_eq!(focus.stroke, 2.0, "FocusOutlineWidth = 2dp");
     assert_eq!(focus.label, ui.color(Role::Primary), "FocusLabelColor");
 
     // A1 没有 Pressed token：按 hover 处理（D11），不是漏做
     assert_eq!(
-        palette(&ui, FieldVariant::Outlined, Interaction::Pressed, false),
+        palette(
+            &ui,
+            Base::CANVAS,
+            FieldVariant::Outlined,
+            Interaction::Pressed,
+            false
+        ),
         hover
     );
 }
@@ -69,7 +94,13 @@ fn outline_colors_and_widths_follow_the_state() {
 #[test]
 fn error_beats_focus_and_paints_everything_error() {
     let ui = ui(SchemeFlavor::Light);
-    let error = palette(&ui, FieldVariant::Outlined, Interaction::Focused, true);
+    let error = palette(
+        &ui,
+        Base::CANVAS,
+        FieldVariant::Outlined,
+        Interaction::Focused,
+        true,
+    );
     assert_eq!(error.line, ui.color(Role::Error));
     assert_eq!(error.label, ui.color(Role::Error));
     assert_eq!(error.supporting, ui.color(Role::Error));
@@ -82,21 +113,33 @@ fn error_beats_focus_and_paints_everything_error() {
 fn disabled_uses_the_token_alphas() {
     for flavor in [SchemeFlavor::Light, SchemeFlavor::Dark] {
         let ui = ui(flavor);
-        let container = interaction::disabled_colors(&ui, Role::Surface).0;
+        let container = interaction::disabled_colors(&ui, Base::CANVAS).0;
 
-        let filled = palette(&ui, FieldVariant::Filled, Interaction::Disabled, false);
+        let filled = palette(
+            &ui,
+            Base::CANVAS,
+            FieldVariant::Filled,
+            Interaction::Disabled,
+            false,
+        );
         assert_eq!(filled.fill, Some(container));
         assert_eq!(
             filled.input,
-            interaction::disabled_content_over_role(&ui, Role::OnSurface, true)
+            interaction::disabled_content_over_role(&ui, Base::CANVAS, Role::OnSurface, true)
         );
 
-        let outlined = palette(&ui, FieldVariant::Outlined, Interaction::Disabled, false);
+        let outlined = palette(
+            &ui,
+            Base::CANVAS,
+            FieldVariant::Outlined,
+            Interaction::Disabled,
+            false,
+        );
         assert_eq!(outlined.fill, None);
         assert_eq!(outlined.line, container, "DisabledOutlineOpacity = 0.12");
         assert_eq!(
             outlined.input,
-            interaction::disabled_content_over_role(&ui, Role::OnSurface, false)
+            interaction::disabled_content_over_role(&ui, Base::CANVAS, Role::OnSurface, false)
         );
         assert_ne!(outlined.input, ui.color(Role::OnSurface), "禁用不许满档");
     }
@@ -107,7 +150,14 @@ fn disabled_uses_the_token_alphas() {
 fn filled_carries_the_container_role() {
     let ui = ui(SchemeFlavor::Light);
     assert_eq!(
-        palette(&ui, FieldVariant::Filled, Interaction::Enabled, false).fill,
+        palette(
+            &ui,
+            Base::CANVAS,
+            FieldVariant::Filled,
+            Interaction::Enabled,
+            false
+        )
+        .fill,
         Some(ui.color(Role::SurfaceContainerHighest)),
         "FilledTextFieldTokens.ContainerColor"
     );
diff --git a/crates/app-iced/src/components/inputs/menu.rs b/crates/app-iced/src/components/inputs/menu.rs
index 9dc7050..f689f4e 100644
--- a/crates/app-iced/src/components/inputs/menu.rs
+++ b/crates/app-iced/src/components/inputs/menu.rs
@@ -42,7 +42,7 @@ use crate::icons;
 use crate::theme::Ui;
 
 use super::super::divider;
-use super::super::interaction::{self, Interaction};
+use super::super::interaction::{self, Base, Interaction};
 use super::super::layout;
 use super::geometry::MenuGeometry;
 
@@ -171,10 +171,10 @@ struct ItemPalette {
 }
 
 /// 解析一项的颜色：选中优先，其余按五态叠状态层（`interaction::overlay_color`）。
-fn item_palette(ui: &Ui, state: Interaction, selected: bool) -> ItemPalette {
+fn item_palette(ui: &Ui, base: Base, state: Interaction, selected: bool) -> ItemPalette {
     if state.is_disabled() {
-        // 禁用：内容 38%（无容器时叠在表面色上；菜单项本身透明）
-        let ink = interaction::disabled_content_over_role(ui, Role::OnSurface, false);
+        // 禁用：内容 38%，叠在**菜单面板的底**上（项本身透明，透出来的就是面板色）
+        let ink = interaction::disabled_content_over_role(ui, base, Role::OnSurface, false);
         return ItemPalette {
             fill: None,
             ink,
@@ -201,14 +201,20 @@ fn item_palette(ui: &Ui, state: Interaction, selected: bool) -> ItemPalette {
     }
 
     ItemPalette {
-        // 状态层叠在**菜单容器色**上（SurfaceContainer），得到不透明结果（D27）
-        fill: interaction::overlay_color(ui, state, Role::OnSurface, Role::SurfaceContainer),
+        // 状态层叠在**菜单容器色**上（`PANEL_BASE` = SurfaceContainer），得到不透明结果（D27）
+        fill: interaction::overlay_color(ui, state, Role::OnSurface, base.role()),
         ink: ui.color(Role::OnSurface),
         icon: ui.color(Role::OnSecondaryContainer),
         shape: ShapeScale::Small,
     }
 }
 
+/// 菜单弹出层的底（**面板画这个色，项就叠在它上面**）。
+///
+/// 8.2 的 `MenuTokens.ContainerColor = SurfaceContainer`：面板用 `ui.color(PANEL_BASE.role())` 画底，
+/// 项的禁用态（38% 内容）与状态层拿同一个 [`Base`] 合成——两边同源，改色不会只改一半（M234）。
+pub const PANEL_BASE: Base = Base::of(Role::SurfaceContainer);
+
 /// 菜单弹出层（`SurfaceContainer` + L2 阴影）。
 pub fn menu<'a, M: Clone + 'a>(ui: &'a Ui, menu: Menu<'a, M>) -> Element<'a, M> {
     let geometry = MenuGeometry::of(ui);
@@ -220,13 +226,13 @@ pub fn menu<'a, M: Clone + 'a>(ui: &'a Ui, menu: Menu<'a, M>) -> Element<'a, M>
         "MenuTokens.ContainerElevation"
     );
     let shadow_spec = elevation.shadow();
-    let panel = ui.color(Role::SurfaceContainer);
+    let panel = ui.color(PANEL_BASE.role());
     let shape = geometry.shape;
 
     let mut rows = column![].width(Length::Fill);
     for entry in menu.entries {
         rows = rows.push(match entry {
-            Entry::Item(item) => item_row(ui, item, geometry),
+            Entry::Item(item) => item_row(ui, PANEL_BASE, item, geometry),
             // 分组分隔线：复用 `divider::full`（一像素线 + OutlineVariant），不自己画
             Entry::Divider => divider::full::<M>(ui),
         });
@@ -256,6 +262,7 @@ pub fn menu<'a, M: Clone + 'a>(ui: &'a Ui, menu: Menu<'a, M>) -> Element<'a, M>
 /// 一行菜单项（用 `button` 承载命中与四态，几何与颜色自绘）。
 fn item_row<'a, M: Clone + 'a>(
     ui: &'a Ui,
+    base: Base,
     item: MenuItem<'a, M>,
     geometry: MenuGeometry,
 ) -> Element<'a, M> {
@@ -265,7 +272,12 @@ fn item_row<'a, M: Clone + 'a>(
         None
     });
     // 选中项的背景也要跟态走：禁用时不许留满档 SecondaryContainer
-    let colors = item_palette(ui, forced.unwrap_or(Interaction::Enabled), item.selected);
+    let colors = item_palette(
+        ui,
+        base,
+        forced.unwrap_or(Interaction::Enabled),
+        item.selected,
+    );
     let body = ui.style(TypeRole::BodyMedium);
 
     let label = text(item.label)
@@ -308,7 +320,7 @@ fn item_row<'a, M: Clone + 'a>(
     let selected = item.selected;
     let style = move |_theme: &iced::Theme, status: button::Status| {
         let state = forced.unwrap_or_else(|| Interaction::from_status(status));
-        let colors = item_palette(ui, state, selected);
+        let colors = item_palette(ui, base, state, selected);
         button::Style {
             background: colors.fill.map(Background::Color),
             text_color: colors.ink,
diff --git a/crates/app-iced/src/components/inputs/menu/tests.rs b/crates/app-iced/src/components/inputs/menu/tests.rs
index 19f041b..e03106f 100644
--- a/crates/app-iced/src/components/inputs/menu/tests.rs
+++ b/crates/app-iced/src/components/inputs/menu/tests.rs
@@ -55,13 +55,13 @@ fn container_uses_surface_container_and_level2_shadow() {
 #[test]
 fn selected_and_disabled_items_use_the_right_roles() {
     let ui = ui(SchemeFlavor::Light);
-    let selected = item_palette(&ui, Interaction::Enabled, true);
+    let selected = item_palette(&ui, PANEL_BASE, Interaction::Enabled, true);
     assert_eq!(selected.fill, Some(ui.color(Role::SecondaryContainer)));
     assert_eq!(selected.ink, ui.color(Role::OnSecondaryContainer));
     assert_eq!(selected.icon, ui.color(Role::OnSecondaryContainer));
 
     // 选中 + hover：状态层叠在 SecondaryContainer 上（不是满档底色）
-    let hovered = item_palette(&ui, Interaction::Hovered, true);
+    let hovered = item_palette(&ui, PANEL_BASE, Interaction::Hovered, true);
     assert_ne!(hovered.fill, selected.fill);
     assert_eq!(
         hovered.fill,
@@ -73,11 +73,11 @@ fn selected_and_disabled_items_use_the_right_roles() {
         )
     );
 
-    let disabled = item_palette(&ui, Interaction::Disabled, true);
+    let disabled = item_palette(&ui, PANEL_BASE, Interaction::Disabled, true);
     assert_eq!(disabled.fill, None, "禁用项不留满档选中底色");
     assert_eq!(
         disabled.ink,
-        interaction::disabled_content_over_role(&ui, Role::OnSurface, false)
+        interaction::disabled_content_over_role(&ui, PANEL_BASE, Role::OnSurface, false)
     );
     assert_ne!(disabled.ink, ui.color(Role::OnSurface));
 }
@@ -86,14 +86,14 @@ fn selected_and_disabled_items_use_the_right_roles() {
 #[test]
 fn item_states_blend_on_the_menu_container() {
     let ui = ui(SchemeFlavor::Light);
-    let rest = item_palette(&ui, Interaction::Enabled, false);
+    let rest = item_palette(&ui, PANEL_BASE, Interaction::Enabled, false);
     assert_eq!(rest.fill, None, "静息不叠色（菜单底色透出来）");
     for state in [
         Interaction::Hovered,
         Interaction::Pressed,
         Interaction::Focused,
     ] {
-        let fill = item_palette(&ui, state, false)
+        let fill = item_palette(&ui, PANEL_BASE, state, false)
             .fill
             .expect("可交互态必须给底色");
         assert_eq!(fill.a, 1.0, "结果必须不透明（D27）");
diff --git a/crates/app-iced/src/components/inputs/search.rs b/crates/app-iced/src/components/inputs/search.rs
index 6f79170..bfa15ee 100644
--- a/crates/app-iced/src/components/inputs/search.rs
+++ b/crates/app-iced/src/components/inputs/search.rs
@@ -38,7 +38,7 @@ use unlucky_design::typography::TypeRole;
 use crate::icons;
 use crate::theme::{Ui, STROKE_PX};
 
-use super::super::interaction::{self, Interaction};
+use super::super::interaction::{self, Base, Interaction};
 use super::super::layout;
 use super::geometry::{SEARCH_MAX_WIDTH, SEARCH_MIN_WIDTH, SEARCH_VIEW_MIN_HEIGHT};
 
@@ -52,6 +52,8 @@ pub struct SearchBar<'a> {
     trailing: Option<IconKind>,
     state: Option<Interaction>,
     width: Length,
+    /// 脚下那一层的底（M234，禁用态合成用）。
+    base: Base,
 }
 
 impl<'a> SearchBar<'a> {
@@ -63,6 +65,7 @@ impl<'a> SearchBar<'a> {
             trailing: Some(IconKind::Filter),
             state: None,
             width: Length::Fill,
+            base: Base::CANVAS,
         }
     }
 
@@ -83,12 +86,22 @@ impl<'a> SearchBar<'a> {
         self.width = width;
         self
     }
+
+    /// **告诉药丸它踩在什么底上**（M234）：禁用态那 12% 的容器叠在这个底上。
+    ///
+    /// 药丸自己的容器色是 `SurfaceContainerHighest`，但**禁用它不画那个色**——禁用画的是
+    /// 「12% 叠父底」，所以这里要的是父底（卡片 = `surfaces::elevated::BASE`），不是它自己。
+    pub fn base(mut self, base: impl Into<Base>) -> Self {
+        self.base = base.into();
+        self
+    }
 }
 
 /// 搜索条内的一行内容（bar 与 view 头部共用，保证「展开时头部不跳」——20.6）。
 #[allow(clippy::too_many_arguments)]
 fn bar_content<'a, M: Clone + 'a>(
     ui: &'a Ui,
+    base: Base,
     value: &'a str,
     placeholder: &'a str,
     trailing: Option<IconKind>,
@@ -102,7 +115,7 @@ fn bar_content<'a, M: Clone + 'a>(
     let icon_offset = icon_edge - bar.pad_start;
 
     let ink = if state.is_disabled() {
-        interaction::disabled_content_over_role(ui, Role::OnSurface, true)
+        interaction::disabled_content_over_role(ui, base, Role::OnSurface, true)
     } else {
         ui.color(Role::OnSurface)
     };
@@ -190,7 +203,8 @@ pub fn search_bar<'a, M: Clone + 'a>(
     let height = ui.metrics().search_bar_height;
 
     let background = if state.is_disabled() {
-        interaction::disabled_colors(ui, Role::Surface).0
+        // 禁用：12% 叠在**药丸脚下的底**上（不是药丸自己的 SurfaceContainerHighest）
+        interaction::disabled_colors(ui, bar.base).0
     } else {
         // 规格卡里搜索药丸与 filled 字段是**同一个底**（`SurfaceContainerHighest`）：
         // M229 r1 用的是 `High`，比 filled 字段低一档，两块并排时能看出色差（复审 F2 裁决抬档）。
@@ -212,6 +226,7 @@ pub fn search_bar<'a, M: Clone + 'a>(
 
     container(bar_content(
         ui,
+        bar.base,
         bar.value,
         bar.placeholder,
         bar.trailing,
@@ -269,7 +284,8 @@ pub fn search_view<'a, M: Clone + 'a>(
 ) -> Element<'a, M> {
     // 展开面板**不跟着药丸抬档**：它是浮层（菜单语言，`SurfaceContainerHigh`），
     // 规格卡只画了收起的药丸。两块不同档是层级差，不是漏改（复审 F2 只裁药丸）。
-    let panel = ui.color(Role::SurfaceContainerHigh);
+    let panel_role = Role::SurfaceContainerHigh;
+    let panel = ui.color(panel_role);
     let header_height = ui.metrics().search_bar_height;
     let body_style = ui.style(TypeRole::BodyMedium);
 
@@ -327,6 +343,7 @@ pub fn search_view<'a, M: Clone + 'a>(
     let panel_content = column![
         container(bar_content(
             ui,
+            Base::of(panel_role),
             view.value,
             view.placeholder,
             Some(IconKind::Close),
diff --git a/crates/app-iced/src/components/inputs/slider.rs b/crates/app-iced/src/components/inputs/slider.rs
index dccf756..c986bf2 100644
--- a/crates/app-iced/src/components/inputs/slider.rs
+++ b/crates/app-iced/src/components/inputs/slider.rs
@@ -40,13 +40,12 @@ use iced::advanced::widget::{tree, Tree};
 use iced::advanced::{mouse, Clipboard, Shell, Widget};
 use iced::{Background, Border, Color, Element, Event, Length, Rectangle, Size};
 
-use unlucky_design::color::Role;
-
 use crate::theme::Ui;
 
-use super::super::interaction::{self, Interaction, Tracker};
-use super::geometry::{SliderGeometry, HANDLE_HEIGHT, HANDLE_WIDTH_ACTIVE, STOP_GAP, STOP_SIZE};
+use super::super::interaction::{Base, Interaction, Tracker};
+use super::geometry::{SliderGeometry, HANDLE_HEIGHT, STOP_GAP, STOP_SIZE};
 
+mod paint;
 mod track;
 
 pub use track::TrackGeometry;
@@ -60,6 +59,8 @@ pub struct Slider<'a, M> {
     steps: Option<u32>,
     on_change: Option<Box<dyn Fn(f32) -> M + 'a>>,
     forced: Option<Interaction>,
+    /// 脚下那一层的底（M234，禁用态合成用）。
+    base: Base,
 }
 
 impl<'a, M> Slider<'a, M> {
@@ -71,6 +72,7 @@ impl<'a, M> Slider<'a, M> {
             steps: None,
             on_change: None,
             forced: None,
+            base: Base::CANVAS,
         }
     }
 
@@ -93,6 +95,14 @@ impl<'a, M> Slider<'a, M> {
         self
     }
 
+    /// **告诉滑块它踩在什么底上**（M234）：禁用态的 12% 未激活轨与 38% 内容叠在这个底上。
+    ///
+    /// 放进卡片/面板里必须给（卡片 = `surfaces::elevated::BASE`）。
+    pub fn base(mut self, base: impl Into<Base>) -> Self {
+        self.base = base.into();
+        self
+    }
+
     /// 当前比例（量化后）。
     fn value(&self) -> f32 {
         quantize(self.fraction, self.steps)
@@ -240,30 +250,13 @@ where
             .forced
             .unwrap_or_else(|| tree.state.downcast_ref::<State>().tracker.state());
         let disabled = state.is_disabled();
-
-        let (active_color, inactive_color, handle_color, handle_width) = if disabled {
-            (
-                interaction::disabled_content_over_role(ui, Role::OnSurface, false),
-                interaction::disabled_colors(ui, Role::Surface).0,
-                interaction::disabled_content_over_role(ui, Role::OnSurface, false),
-                geometry.handle,
-            )
-        } else {
-            // 状态层只叠在 handle 上（D16）：α 全部来自 interaction（hover 8 / focus 10 / pressed 10）
-            let handle_color =
-                interaction::overlay_color(ui, state, Role::OnSurface, Role::Primary)
-                    .unwrap_or_else(|| ui.color(Role::Primary));
-            let handle_width = match state {
-                Interaction::Focused | Interaction::Pressed => HANDLE_WIDTH_ACTIVE,
-                _ => geometry.handle,
-            };
-            (
-                ui.color(Role::Primary),
-                ui.color(Role::SecondaryContainer),
-                handle_color,
-                handle_width,
-            )
-        };
+        let colors = paint::colors(ui, self.base, state, geometry.handle);
+        let (active_color, inactive_color, handle_color, handle_width) = (
+            colors.active,
+            colors.inactive,
+            colors.handle,
+            colors.handle_width,
+        );
 
         let centre_y = bounds.y + bounds.height / 2.0;
         let track_x = bounds.x;
diff --git a/crates/app-iced/src/components/inputs/slider/paint.rs b/crates/app-iced/src/components/inputs/slider/paint.rs
new file mode 100644
index 0000000..6d38fae
--- /dev/null
+++ b/crates/app-iced/src/components/inputs/slider/paint.rs
@@ -0,0 +1,55 @@
+//! 滑块的颜色求值（M234 从 `slider.rs` 的 `draw` 里搬出来，顺手收一个 [`Base`]）。
+//!
+//! 搬出来的两个理由：① `slider.rs` 已顶到 399 行，加 `.base(..)` 之前必须腾地方；
+//! ② 禁用态那三笔颜色原来在 `draw` 里写死 `Role::Surface` 当合成底（M234 的病灶），
+//! 搬进纯函数后可以被单测直接钉住「叠在哪个底上」。
+
+use iced::Color;
+
+use unlucky_design::color::Role;
+
+use crate::theme::Ui;
+
+use super::super::super::interaction::{self, Base, Interaction};
+use super::super::geometry::HANDLE_WIDTH_ACTIVE;
+
+/// 滑块一笔要的三个颜色 + handle 宽。
+#[derive(Debug, Clone, Copy, PartialEq)]
+pub(super) struct Colors {
+    /// 激活段（左侧已走部分）。
+    pub(super) active: Color,
+    /// 未激活段。
+    pub(super) inactive: Color,
+    /// handle（4×44 竖条）。
+    pub(super) handle: Color,
+    /// handle 宽（focus / pressed 收窄）。
+    pub(super) handle_width: f32,
+}
+
+/// 五态 → 三笔颜色（`HANDLE_WIDTH_ACTIVE` 只在 focus/pressed 用）。
+///
+/// 禁用（11.6）：激活段与 handle `OnSurface`@38%、未激活轨 @12%，三者都叠在 `base` 上
+/// ——`base` 是滑块**脚下那一层**（卡片 = `surfaces::elevated::BASE`），不是恒定的画布色。
+pub(super) fn colors(ui: &Ui, base: Base, state: Interaction, handle: f32) -> Colors {
+    if state.is_disabled() {
+        return Colors {
+            active: interaction::disabled_content_over_role(ui, base, Role::OnSurface, false),
+            inactive: interaction::disabled_colors(ui, base).0,
+            handle: interaction::disabled_content_over_role(ui, base, Role::OnSurface, false),
+            handle_width: handle,
+        };
+    }
+    // 状态层只叠在 handle 上（D16）：α 全部来自 interaction（hover 8 / focus 10 / pressed 10）
+    let handle_color = interaction::overlay_color(ui, state, Role::OnSurface, Role::Primary)
+        .unwrap_or_else(|| ui.color(Role::Primary));
+    let handle_width = match state {
+        Interaction::Focused | Interaction::Pressed => HANDLE_WIDTH_ACTIVE,
+        _ => handle,
+    };
+    Colors {
+        active: ui.color(Role::Primary),
+        inactive: ui.color(Role::SecondaryContainer),
+        handle: handle_color,
+        handle_width,
+    }
+}
diff --git a/crates/app-iced/src/components/interaction/base.rs b/crates/app-iced/src/components/interaction/base.rs
new file mode 100644
index 0000000..81cfd2f
--- /dev/null
+++ b/crates/app-iced/src/components/interaction/base.rs
@@ -0,0 +1,83 @@
+//! 禁用态的**底**：控件脚下那一层容器实际画出来的底色（M234）。
+//!
+//! ## 为什么不是一个 `Role::Surface`
+//!
+//! 禁用态的容器（按钮 10% / 面状控件 12%）与内容（38%）都要**预先合成成不透明色**
+//! （D27：GPU/CPU 两档逐像素一致，所以不许把 α 交给渲染器混合）。合成必须知道「叠在什么上」，
+//! 而这个「什么」是**宿主容器**的属性，不是控件的属性：
+//!
+//! ```text
+//! 画布（Surface）      ← 页面底色
+//!   └ 卡片（SurfaceContainer）      ← `surfaces::elevated::card`
+//!       └ 面板（SurfaceContainerLow）← 取景板 / Card 层
+//!           └ 禁用按钮（OnSurface@10% 叠在面板底上）
+//! ```
+//!
+//! M229 之前 `disabled.rs` 的入口签名是 `(ui, surface: Role)`，而**所有调用点都传死
+//! `Role::Surface`** —— 于是卡片里的禁用按钮把 10% 叠在画布色上，出来是一块与卡片底
+//! 不协调的灰（M223 记的「CR 1.05、形丢失」）。参数在、语义也在，只是没人给真值。
+//!
+//! ## 纪律：底由**画那个底的容器**给
+//!
+//! 每个自己画底的容器**导出 `BASE` 常量**，画的时候用同一个 `Role`、给子控件时给这个常量
+//! （见 [`super::super::surfaces::elevated::BASE`]、`inputs::menu::PANEL_BASE`）。两边同源，
+//! 改色不会漂一半。
+//!
+//! iced 没有「环境上下文」（样式闭包只拿得到 `&Theme`，拿不到父容器的样式），所以这条信息
+//! **只能显式往下传**：容器 → 控件（`.base(..)`）→ 禁用色求值。控件自己不猜。
+//!
+//! ## 抓得住 / 抓不住
+//!
+//! - 抓得住：合成用了哪个 `Role`（`interaction::disabled::tests` 的逐值断言、gallery 的像素 probe）；
+//! - 抓不住：① 容器画的是**合成色**（半透明面板 α、状态层叠过的底）——`Base` 只装一个 `Role`；
+//!   ② 调用点给了**错的** `Role`（机制不校验语义，判据只能落在「给的底对不对」的像素上）；
+//!   ③ 忘了调 `.base(..)` 时回落到 [`Base::CANVAS`]，编译期不会报错（文档 + 像素 probe 兜）。
+
+use unlucky_design::color::Role;
+
+/// 控件脚下那一层的底（容器自己画的角色，**不是**「反正是 surface」）。
+#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
+pub struct Base(Role);
+
+impl Base {
+    /// 画布底（`Surface`）：控件**直接**摆在页面/画布上时用它。
+    ///
+    /// 这也是各控件 `.base(..)` 的默认值——默认值只对「没有容器」这一种情形成立，
+    /// 放进卡片/面板/浮层里**必须**换成那个容器的 `BASE`。
+    pub const CANVAS: Base = Base(Role::Surface);
+
+    /// 从容器**画自己底时用的那个角色**构造（容器应导出一个 `BASE` 常量走这条路）。
+    pub const fn of(role: Role) -> Self {
+        Self(role)
+    }
+
+    /// 该底对应的角色（合成时取色用）。
+    pub const fn role(self) -> Role {
+        self.0
+    }
+}
+
+/// 容器也可以直接把**自己的角色**传进来（`disabled_*` 的入口收 `impl Into<Base>`）：
+/// 这样历史调用点不必全改签名，但语义只有一条——「你脚下那一层是谁」。
+impl From<Role> for Base {
+    fn from(role: Role) -> Self {
+        Self(role)
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    /// 画布底就是画布角色：`Base` 不许偷偷改语义。
+    #[test]
+    fn canvas_is_surface_and_of_keeps_the_role() {
+        assert_eq!(Base::CANVAS.role(), Role::Surface);
+        assert_eq!(
+            Base::of(Role::SurfaceContainer).role(),
+            Role::SurfaceContainer
+        );
+        // 容器底与画布底**不是同一个值**：这一条红了说明 `Base` 把角色丢了
+        assert_ne!(Base::of(Role::SurfaceContainer), Base::CANVAS);
+    }
+}
diff --git a/crates/app-iced/src/components/interaction/disabled.rs b/crates/app-iced/src/components/interaction/disabled.rs
index 1b05190..59af725 100644
--- a/crates/app-iced/src/components/interaction/disabled.rs
+++ b/crates/app-iced/src/components/interaction/disabled.rs
@@ -34,46 +34,77 @@ use unlucky_design::color::{Role, Scheme};
 
 use crate::theme::{to_iced, Ui};
 
+use super::base::Base;
+
+// 四个入口都收 `impl Into<Base>`：容器导出的 `BASE` 常量（推荐）与裸 `Role`（历史调用点，
+// 例如 `pages/settings/java/tests/marker.rs`）都能进来。**没有隐式默认值**——不给就是编译错误，
+// 这一条正是 M229 缺的：参数在、语义在，只是调用点全传了 `Role::Surface`。
+
 /// 禁用态内容色（**按角色、按有没有容器**求值）——A1 口径的入口（**面状控件族**的底）。
 ///
+/// - `base`：控件**脚下那一层的底**（[`Base`]）。容器给的 `BASE` 常量，不是猜；
 /// - `role`：由变体决定（Filled/Outlined/Text/Elevated = `OnSurfaceVariant`；
 ///   FilledTonal 与三式 IconButton = `OnSurface`，见 `Variant::disabled_content`）；
 /// - `on_container = true`：叠在**面状控件族的 12% 容器**（[`DISABLED_SURFACE_ALPHA`]）上
-///   （Filled TextField / 有容器控件在 12% 底上求内容时）；
-///   `false`：直接叠在 **surface** 上（Text / Outlined / standard IconButton / 描边类控件的内容）。
+///   （Filled TextField / 有容器控件在 12% 底上求内容时），容器本身叠在 `base` 上；
+///   `false`：直接叠在 `base` 上（Text / Outlined / standard IconButton / 描边类控件的内容）。
 ///
 /// **按钮家族不要用这个函数**（按钮容器是 10%）：走 [`disabled_button_content`]。
 ///
 /// 之前这里写死 `OnSurfaceVariant` 且只有一个「底」，导致 FilledTonal 与 IconButton 两族偏浅
 /// 15/255（视觉 r3 用像素量的）。
-pub fn disabled_content_over_role(ui: &Ui, role: Role, on_container: bool) -> Color {
+pub fn disabled_content_over_role(
+    ui: &Ui,
+    base: impl Into<Base>,
+    role: Role,
+    on_container: bool,
+) -> Color {
     // **取 `Ui` 里已注入的方案**，不重算 baseline：M229 之后产品方案是品牌色板
     // （Ink / Silver），照 baseline 重算会画出旧的天蓝中性色（复审 F1）。
-    disabled_content_with_alpha(ui.scheme(), role, on_container, DISABLED_SURFACE_ALPHA)
+    disabled_content_with_alpha(
+        ui.scheme(),
+        base.into(),
+        role,
+        on_container,
+        DISABLED_SURFACE_ALPHA,
+    )
 }
 
 /// 禁用态内容色——**按钮家族**（`on_container`：是否叠在本族 10% 容器上）。
 ///
 /// 与 [`disabled_content_over_role`] 的差别只有「底」的 α：按钮 10%、面状控件 12%。
 /// 两个入口分开是 M86 的结论：合成一个数会让一族永远差 1/255，肉眼看不见、只有 probe 会红。
-pub fn disabled_button_content(ui: &Ui, role: Role, on_container: bool) -> Color {
-    disabled_content_with_alpha(ui.scheme(), role, on_container, DISABLED_CONTAINER_ALPHA)
+pub fn disabled_button_content(
+    ui: &Ui,
+    base: impl Into<Base>,
+    role: Role,
+    on_container: bool,
+) -> Color {
+    disabled_content_with_alpha(
+        ui.scheme(),
+        base.into(),
+        role,
+        on_container,
+        DISABLED_CONTAINER_ALPHA,
+    )
 }
 
 /// 两个族共用的内容色求值（「底」的 α 由调用方给）。
 fn disabled_content_with_alpha(
     scheme: &Scheme,
+    base: Base,
     role: Role,
     on_container: bool,
     container_alpha: f32,
 ) -> Color {
+    let underneath = scheme.get(base.role());
     let base = if on_container {
         scheme
             .get(Role::OnSurface)
             .with_alpha(container_alpha)
-            .over(scheme.get(Role::Surface))
+            .over(underneath)
     } else {
-        scheme.get(Role::Surface)
+        underneath
     };
 
     to_iced(
@@ -99,29 +130,32 @@ fn disabled_content_with_alpha(
 ///
 /// 顺序必须「先容器后内容」：Compose 也是这么画的，先叠容器再叠 label，
 /// 所以内容叠的角色是容器实色而不是底下的 surface。
-pub fn disabled_colors(ui: &Ui, surface: Role) -> (Color, Color) {
-    disabled_colors_with_alpha(ui, surface, DISABLED_SURFACE_ALPHA)
+///
+/// ⚠️ **`base` 必须是控件脚下那一层的底**（[`Base`]）：M229 之前这里的参数名叫 `surface`，
+/// 而 8 个调用点全传 `Role::Surface`，于是卡片/面板里的禁用控件把 12% 叠在画布色上（M234）。
+pub fn disabled_colors(ui: &Ui, base: impl Into<Base>) -> (Color, Color) {
+    disabled_colors_with_alpha(ui, base.into(), DISABLED_SURFACE_ALPHA)
 }
 
 /// 禁用态的一对颜色 `(容器, 内容)`——**按钮家族**（10% 容器）。
 ///
-/// - 容器 = `OnSurface` @ 10%（[`DISABLED_CONTAINER_ALPHA`]）叠在 `surface` 上；
+/// - 容器 = `OnSurface` @ 10%（[`DISABLED_CONTAINER_ALPHA`]）叠在 `base` 上；
 /// - 内容 = **默认** `OnSurfaceVariant` @ 38%；按变体的取值走 [`disabled_button_content`]。
 ///
 /// 除了按钮家族，**没有别的消费者**：面状控件（chip / slider 轨道 / switch 轨道 / 描边）走
 /// [`disabled_colors`] 的 12%。
-pub fn disabled_button_colors(ui: &Ui, surface: Role) -> (Color, Color) {
-    disabled_colors_with_alpha(ui, surface, DISABLED_CONTAINER_ALPHA)
+pub fn disabled_button_colors(ui: &Ui, base: impl Into<Base>) -> (Color, Color) {
+    disabled_colors_with_alpha(ui, base.into(), DISABLED_CONTAINER_ALPHA)
 }
 
-/// 两个族共用的求值：容器 = `OnSurface` @ `container_alpha` 叠在 `surface` 上，内容 = 38% 叠在容器上。
-fn disabled_colors_with_alpha(ui: &Ui, surface: Role, container_alpha: f32) -> (Color, Color) {
+/// 两个族共用的求值：容器 = `OnSurface` @ `container_alpha` 叠在 `base` 上，内容 = 38% 叠在容器上。
+fn disabled_colors_with_alpha(ui: &Ui, base: Base, container_alpha: f32) -> (Color, Color) {
     let scheme = ui.scheme();
-    let base = scheme.get(surface);
+    let underneath = scheme.get(base.role());
     let container = scheme
         .get(Role::OnSurface)
         .with_alpha(container_alpha)
-        .over(base);
+        .over(underneath);
     // 这里是**默认口径**（OnSurfaceVariant）；按变体取值请走 [`disabled_content_over_role`]
     // ——FilledTonal 与三式 IconButton 的禁用内容是 `OnSurface`（A1）。
     let content = scheme
diff --git a/crates/app-iced/src/components/interaction/disabled/tests.rs b/crates/app-iced/src/components/interaction/disabled/tests.rs
index 528b17b..fed31d7 100644
--- a/crates/app-iced/src/components/interaction/disabled/tests.rs
+++ b/crates/app-iced/src/components/interaction/disabled/tests.rs
@@ -71,7 +71,7 @@ fn surface_family_disabled_colors_are_the_12_percent_class() {
             .with_alpha(EXPECTED_SURFACE_ALPHA)
             .over(base);
 
-        let (surface, surface_content) = disabled_colors(&ui, Role::Surface);
+        let (surface, surface_content) = disabled_colors(&ui, Base::CANVAS);
         assert_eq!(
             surface,
             to_iced(expected_container),
@@ -102,7 +102,7 @@ fn surface_family_disabled_colors_are_the_12_percent_class() {
             "{flavor:?}：内容必须叠在容器上"
         );
         // 跨族对照：面状族的合成色必须与按钮族不同（两族一旦合流，这条红）
-        let (button, _) = disabled_button_colors(&ui, Role::Surface);
+        let (button, _) = disabled_button_colors(&ui, Base::CANVAS);
         assert_ne!(
             surface, button,
             "{flavor:?}：面状族 12% 与按钮族 10% 必须落在不同像素值上"
@@ -133,7 +133,7 @@ fn button_family_disabled_colors_are_the_10_percent_class() {
             .with_alpha(EXPECTED_BUTTON_ALPHA)
             .over(base);
 
-        let (button, button_content) = disabled_button_colors(&ui, Role::Surface);
+        let (button, button_content) = disabled_button_colors(&ui, Base::CANVAS);
         assert_eq!(
             button,
             to_iced(expected_container),
@@ -149,7 +149,7 @@ fn button_family_disabled_colors_are_the_10_percent_class() {
             ),
         );
 
-        let (surface, _) = disabled_colors(&ui, Role::Surface);
+        let (surface, _) = disabled_colors(&ui, Base::CANVAS);
         assert_ne!(
             button, surface,
             "{flavor:?}：10% 与 12% 必须落在不同像素值上（合成一个数就是这次要防的回归）"
@@ -158,18 +158,18 @@ fn button_family_disabled_colors_are_the_10_percent_class() {
         // 内容色同理：按钮 38% 叠 10% 底 ≠ 面状 38% 叠 12% 底
         assert_ne!(
             button_content,
-            disabled_content_over_role(&ui, Role::OnSurfaceVariant, true),
+            disabled_content_over_role(&ui, Base::CANVAS, Role::OnSurfaceVariant, true),
             "{flavor:?}：两族的「有容器」内容色不能同源"
         );
         assert_eq!(
-            disabled_button_content(&ui, Role::OnSurfaceVariant, true),
+            disabled_button_content(&ui, Base::CANVAS, Role::OnSurfaceVariant, true),
             button_content,
             "{flavor:?}：按钮内容入口必须与按钮颜色入口同源"
         );
         // 无容器时两族完全一致（都叠 surface）——差异只在「有容器」那一支
         assert_eq!(
-            disabled_button_content(&ui, Role::OnSurfaceVariant, false),
-            disabled_content_over_role(&ui, Role::OnSurfaceVariant, false),
+            disabled_button_content(&ui, Base::CANVAS, Role::OnSurfaceVariant, false),
+            disabled_content_over_role(&ui, Base::CANVAS, Role::OnSurfaceVariant, false),
             "{flavor:?}：没有容器时不该有族差异"
         );
     }
@@ -192,7 +192,7 @@ fn disabled_colors_follow_the_brand_board_not_the_tone_baseline() {
         let baseline = Scheme::baseline(flavor);
 
         // ① 面状控件族的容器（chip 描边 / slider 未激活轨 / switch 轨道）
-        let (surface, _surface_content) = disabled_colors(&ui, Role::Surface);
+        let (surface, _surface_content) = disabled_colors(&ui, Base::CANVAS);
         let expect_surface = to_iced(
             board
                 .get(Role::OnSurface)
@@ -216,12 +216,12 @@ fn disabled_colors_follow_the_brand_board_not_the_tone_baseline() {
         );
 
         // ② 按钮族的容器
-        let (button, _) = disabled_button_colors(&ui, Role::Surface);
+        let (button, _) = disabled_button_colors(&ui, Base::CANVAS);
         assert_ne!(button, surface, "{flavor:?}：两族 α 仍要可区分");
 
         // ③ 内容色（两个入口）
         assert_eq!(
-            disabled_content_over_role(&ui, Role::OnSurfaceVariant, true),
+            disabled_content_over_role(&ui, Base::CANVAS, Role::OnSurfaceVariant, true),
             to_iced(
                 board
                     .get(Role::OnSurfaceVariant)
@@ -236,7 +236,7 @@ fn disabled_colors_follow_the_brand_board_not_the_tone_baseline() {
             "{flavor:?}：面状控件族内容色要按色板合成"
         );
         assert_eq!(
-            disabled_button_content(&ui, Role::OnSurfaceVariant, true),
+            disabled_button_content(&ui, Base::CANVAS, Role::OnSurfaceVariant, true),
             to_iced(
                 board
                     .get(Role::OnSurfaceVariant)
@@ -267,6 +267,108 @@ fn disabled_colors_follow_the_brand_board_not_the_tone_baseline() {
     }
 }
 
+/// **M234 的主判据**：禁用态的合成必须用**给的底**，不是画布色。
+///
+/// 卡片（`SurfaceContainer`）与面板（`SurfaceContainerLow`）里各放一个禁用控件时，
+/// 10%（按钮族）/ 12%（面状族）那一层要叠在**卡/面板的底**上；叠在 `Surface` 上就是 M223
+/// 记的「CR 1.05、形丢失」。
+///
+/// 抓得住：① 入口把 `base` 丢了（内部又写死 `Role::Surface`）；② 入口把两个族的 α 合成一个数；
+/// ③ 调用点给了画布底（这条测试只证「给了卡片底 → 算出卡片色」，调用点是否真的给了由
+/// `buttons::tests::a_disabled_button_composites_over_the_base_it_is_given` 与 gallery 的像素
+/// probe 分别守）。
+///
+/// 抓不住：① 容器画的是**合成色**（半透明面板 α、叠过状态层的底）——`Base` 只装一个 `Role`；
+/// ② 卡/面板组件的 `BASE` 常量与它自己画的色不一致（那条由 `surfaces::elevated::tests` 与
+/// 像素 probe 守）；③ GPU(wgpu) 档（本测试是纯值，两档同源同值）。
+#[test]
+fn disabled_paint_composites_over_the_base_it_is_given() {
+    use unlucky_design::color::BrandBoard;
+    use unlucky_design::color::Role;
+
+    const BUTTON_ALPHA: f32 = 0.10;
+    const SURFACE_ALPHA: f32 = 0.12;
+    const CONTENT_ALPHA: f32 = 0.38;
+
+    for flavor in [SchemeFlavor::Light, SchemeFlavor::Dark] {
+        let ui = ui(flavor);
+        let scheme = BrandBoard::for_flavor(flavor).scheme();
+        let card = Base::of(Role::SurfaceContainer);
+        let panel = Base::of(Role::SurfaceContainerLow);
+
+        // 期望值一律**独立算**（写死 α + 直接取色板角色），不调被测常量。
+        let over = |base: Role, alpha: f32| {
+            to_iced(
+                scheme
+                    .get(Role::OnSurface)
+                    .with_alpha(alpha)
+                    .over(scheme.get(base)),
+            )
+        };
+
+        // ① 按钮族 10%：卡片底 / 面板底 / 画布底三档互不相等
+        let (card_button, card_button_ink) = disabled_button_colors(&ui, card);
+        let (panel_button, _) = disabled_button_colors(&ui, panel);
+        let (canvas_button, canvas_button_ink) = disabled_button_colors(&ui, Base::CANVAS);
+        assert_eq!(
+            card_button,
+            over(Role::SurfaceContainer, BUTTON_ALPHA),
+            "{flavor:?}：卡片里的禁用按钮容器 = on-surface@10% 叠**卡片底**"
+        );
+        assert_eq!(
+            panel_button,
+            over(Role::SurfaceContainerLow, BUTTON_ALPHA),
+            "{flavor:?}：面板里的禁用按钮容器 = on-surface@10% 叠**面板底**"
+        );
+        assert_ne!(card_button, canvas_button, "{flavor:?}：卡片底 ≠ 画布底");
+        assert_ne!(panel_button, canvas_button, "{flavor:?}：面板底 ≠ 画布底");
+        assert_ne!(card_button, panel_button, "{flavor:?}：卡片底 ≠ 面板底");
+
+        // ② 面状控件族 12%（字段容器 / chip 容器 / switch 轨道）
+        let (card_surface, _) = disabled_colors(&ui, card);
+        let (panel_surface, _) = disabled_colors(&ui, panel);
+        let (canvas_surface, _) = disabled_colors(&ui, Base::CANVAS);
+        assert_eq!(
+            card_surface,
+            over(Role::SurfaceContainer, SURFACE_ALPHA),
+            "{flavor:?}：卡片里的禁用字段容器 = on-surface@12% 叠**卡片底**"
+        );
+        assert_eq!(
+            panel_surface,
+            over(Role::SurfaceContainerLow, SURFACE_ALPHA),
+            "{flavor:?}：面板里的禁用字段容器 = on-surface@12% 叠**面板底**"
+        );
+        assert_ne!(card_surface, canvas_surface);
+        assert_ne!(panel_surface, canvas_surface);
+
+        // ③ 内容色也跟着底走（38% 叠在容器上 / 直接叠在底上，两支都要换底）
+        assert_eq!(
+            disabled_button_content(&ui, card, Role::OnSurfaceVariant, true),
+            to_iced(
+                scheme
+                    .get(Role::OnSurfaceVariant)
+                    .with_alpha(CONTENT_ALPHA)
+                    .over(
+                        scheme
+                            .get(Role::OnSurface)
+                            .with_alpha(BUTTON_ALPHA)
+                            .over(scheme.get(Role::SurfaceContainer))
+                    )
+            ),
+            "{flavor:?}：有容器的内容色 = 38% 叠(10% 叠卡片底)"
+        );
+        assert_ne!(
+            card_button_ink, canvas_button_ink,
+            "{flavor:?}：内容叠的容器换了底"
+        );
+        assert_ne!(
+            disabled_content_over_role(&ui, card, Role::OnSurface, false),
+            disabled_content_over_role(&ui, Base::CANVAS, Role::OnSurface, false),
+            "{flavor:?}：无容器时 38% 也必须叠在**给的底**上"
+        );
+    }
+}
+
 /// iced 颜色 → 8bit 通道（像素值，报告里的证据就用它）。
 fn channels(color: Color) -> (u8, u8, u8) {
     (
diff --git a/crates/app-iced/src/components/interaction/mod.rs b/crates/app-iced/src/components/interaction/mod.rs
index 8fd640a..64487ac 100644
--- a/crates/app-iced/src/components/interaction/mod.rs
+++ b/crates/app-iced/src/components/interaction/mod.rs
@@ -39,6 +39,13 @@
 //! 上表右列是**唯一**允许的取值口；左列只是给人看的，代码里一个数字都不许出现
 //! （`components::gate` 会扫）。
 //!
+//! ## 合成的「底」是参数，不是常量（M234）
+//!
+//! 四个入口都收一个 [`Base`]——控件**脚下那一层的底**，由画那个底的容器导出
+//! （`surfaces::elevated::BASE` / `inputs::menu::PANEL_BASE` / 各控件的 `.base(..)`）。
+//! M229 之前这个值恒等于 `Role::Surface`，于是卡片/面板里的禁用控件把 10%/12% 叠在画布色上
+//! （M223 的「CR 1.05、形丢失」）。**不许**在入口内部再写一个默认值回来。
+//!
 //! ## 两个消费形态
 //!
 //! 1. **iced `button` 系**（本 mission 的按钮家族）：拿 [`Interaction`] 直接配 [`overlay_color`]；
@@ -144,8 +151,10 @@ pub fn overlay_color(ui: &Ui, state: Interaction, content: Role, container: Role
         .map(|layer| ui.state_over(layer, content, container))
 }
 
+mod base;
 mod disabled;
 
+pub use base::Base;
 pub use disabled::{
     disabled_button_colors, disabled_button_content, disabled_colors, disabled_content_over_role,
 };
diff --git a/crates/app-iced/src/components/navigation/drawer.rs b/crates/app-iced/src/components/navigation/drawer.rs
index 2a8a690..4727760 100644
--- a/crates/app-iced/src/components/navigation/drawer.rs
+++ b/crates/app-iced/src/components/navigation/drawer.rs
@@ -34,12 +34,19 @@ use unlucky_design::typography::TypeRole;
 use crate::theme::Ui;
 
 use super::super::divider;
+use super::super::interaction::Base;
 use super::geometry::{NavLayout, NavPaneGeometry};
 
 mod item;
 use item::{line, nav_row};
 pub use item::{NavGroup, NavItem};
 
+/// 导航容器的底：§21.3 标准（常驻）= `Surface` + L0 —— 所以项的禁用内容叠在画布色上。
+///
+/// 与 [`navigation`] 的 `ui.layer(MaterialLayer::Canvas)` 同源（`Canvas` 的 surface_role 就是
+/// `Surface`），M234 之后「底」由这里给，项自己不猜。
+pub const BASE: Base = Base::of(Role::Surface);
+
 /// 导航容器（D33：`layout` 决定 88 还是 240，其余全同）。
 #[derive(Debug, Clone)]
 pub struct Navigation<'a, M> {
@@ -110,7 +117,7 @@ pub fn navigation<'a, M: Clone + 'a>(ui: &'a Ui, nav: Navigation<'a, M>) -> Elem
             );
         }
         for item in group.items {
-            body = body.push(nav_row(ui, item, geometry));
+            body = body.push(nav_row(ui, BASE, item, geometry));
         }
     }
 
diff --git a/crates/app-iced/src/components/navigation/drawer/item.rs b/crates/app-iced/src/components/navigation/drawer/item.rs
index 4b4a667..511eba6 100644
--- a/crates/app-iced/src/components/navigation/drawer/item.rs
+++ b/crates/app-iced/src/components/navigation/drawer/item.rs
@@ -14,7 +14,7 @@ use unlucky_design::typography::TypeRole;
 use crate::icons;
 use crate::theme::Ui;
 
-use super::super::super::interaction::{self, Interaction};
+use super::super::super::interaction::{self, Base, Interaction};
 use super::super::super::layout;
 use super::super::geometry::{NavLayout, NavPaneGeometry};
 
@@ -109,12 +109,13 @@ pub(super) struct ItemPalette {
 
 pub(super) fn palette(
     ui: &Ui,
+    base: Base,
     layout: NavLayout,
     state: Interaction,
     selected: bool,
 ) -> ItemPalette {
     if state.is_disabled() {
-        let ink = interaction::disabled_content_over_role(ui, Role::OnSurface, false);
+        let ink = interaction::disabled_content_over_role(ui, base, Role::OnSurface, false);
         return ItemPalette {
             pill: None,
             icon: ink,
@@ -174,6 +175,7 @@ pub(super) fn line<'a, M: 'a>(
 /// 一项（rail：图标在上、标签在下；drawer：图标在左、标签在右）。
 pub(super) fn nav_row<'a, M: Clone + 'a>(
     ui: &'a Ui,
+    base: Base,
     item: NavItem<'a, M>,
     geometry: NavPaneGeometry,
 ) -> Element<'a, M> {
@@ -183,7 +185,7 @@ pub(super) fn nav_row<'a, M: Clone + 'a>(
         None
     });
     let state = forced.unwrap_or(Interaction::Enabled);
-    let colors = palette(ui, geometry.layout, state, item.selected);
+    let colors = palette(ui, base, geometry.layout, state, item.selected);
     let radius = iced::border::Radius::new(geometry.pill_height / 2.0);
 
     let icon = layout::fixed(
diff --git a/crates/app-iced/src/components/navigation/drawer/tests.rs b/crates/app-iced/src/components/navigation/drawer/tests.rs
index c160951..660244e 100644
--- a/crates/app-iced/src/components/navigation/drawer/tests.rs
+++ b/crates/app-iced/src/components/navigation/drawer/tests.rs
@@ -26,7 +26,7 @@ fn ui() -> Ui {
 #[test]
 fn drawer_selected_uses_secondary_container() {
     let ui = ui();
-    let palette = palette(&ui, NavLayout::Drawer, Interaction::Enabled, true);
+    let palette = palette(&ui, BASE, NavLayout::Drawer, Interaction::Enabled, true);
     assert_eq!(palette.pill, Some(ui.color(Role::SecondaryContainer)));
     assert_eq!(palette.icon, ui.color(Role::OnSecondaryContainer));
     assert_eq!(palette.label, ui.color(Role::OnSecondaryContainer));
@@ -36,8 +36,8 @@ fn drawer_selected_uses_secondary_container() {
 #[test]
 fn rail_selected_label_is_secondary() {
     let ui = ui();
-    let rail = palette(&ui, NavLayout::Rail, Interaction::Enabled, true);
-    let drawer = palette(&ui, NavLayout::Drawer, Interaction::Enabled, true);
+    let rail = palette(&ui, BASE, NavLayout::Rail, Interaction::Enabled, true);
+    let drawer = palette(&ui, BASE, NavLayout::Drawer, Interaction::Enabled, true);
     assert_eq!(rail.label, ui.color(Role::Secondary));
     assert_ne!(rail.label, drawer.label, "两条线的选中标签角色不同");
     // 但图标与药丸相同（同一套语言）
@@ -49,7 +49,7 @@ fn rail_selected_label_is_secondary() {
 #[test]
 fn inactive_lifts_to_on_surface() {
     let ui = ui();
-    let resting = palette(&ui, NavLayout::Drawer, Interaction::Enabled, false);
+    let resting = palette(&ui, BASE, NavLayout::Drawer, Interaction::Enabled, false);
     assert_eq!(resting.label, ui.color(Role::OnSurfaceVariant));
     assert_eq!(resting.pill, None);
     for state in [
@@ -57,7 +57,7 @@ fn inactive_lifts_to_on_surface() {
         Interaction::Focused,
         Interaction::Pressed,
     ] {
-        let active = palette(&ui, NavLayout::Drawer, state, false);
+        let active = palette(&ui, BASE, NavLayout::Drawer, state, false);
         assert_eq!(active.label, ui.color(Role::OnSurface), "{state:?}");
         assert_eq!(active.icon, ui.color(Role::OnSurface), "{state:?}");
         assert!(active.pill.is_some(), "{state:?} 必须叠状态层");
@@ -68,10 +68,10 @@ fn inactive_lifts_to_on_surface() {
 #[test]
 fn disabled_draws_no_pill() {
     let ui = ui();
-    let palette = palette(&ui, NavLayout::Drawer, Interaction::Disabled, true);
+    let palette = palette(&ui, BASE, NavLayout::Drawer, Interaction::Disabled, true);
     assert_eq!(
         palette.icon,
-        interaction::disabled_content_over_role(&ui, Role::OnSurface, false)
+        interaction::disabled_content_over_role(&ui, BASE, Role::OnSurface, false)
     );
     assert_eq!(palette.label, palette.icon);
     assert_eq!(palette.pill, None);
diff --git a/crates/app-iced/src/components/navigation/list_item.rs b/crates/app-iced/src/components/navigation/list_item.rs
index 3f44d0a..57531b2 100644
--- a/crates/app-iced/src/components/navigation/list_item.rs
+++ b/crates/app-iced/src/components/navigation/list_item.rs
@@ -49,7 +49,7 @@ use unlucky_design::shape::ShapeScale;
 use crate::icons;
 use crate::theme::Ui;
 
-use super::super::interaction::{self, Interaction};
+use super::super::interaction::{self, Base, Interaction};
 use super::super::layout;
 use super::geometry::{
     typography_headline, typography_overline, typography_supporting, ListItemGeometry,
@@ -66,6 +66,8 @@ pub struct ListItem<'a, M> {
     on_press: Option<M>,
     selected: bool,
     state: Option<Interaction>,
+    /// 脚下那一层的底（M234，禁用态合成用）。
+    base: Base,
 }
 
 impl<'a, M> ListItem<'a, M> {
@@ -80,6 +82,7 @@ impl<'a, M> ListItem<'a, M> {
             on_press: Some(on_press),
             selected: false,
             state: None,
+            base: Base::CANVAS,
         }
     }
 
@@ -119,6 +122,12 @@ impl<'a, M> ListItem<'a, M> {
         self
     }
 
+    /// **告诉列表项它踩在什么底上**（M234）：禁用态的 38% 内容叠在这个底上。
+    pub fn base(mut self, base: impl Into<Base>) -> Self {
+        self.base = base.into();
+        self
+    }
+
     /// 转禁用：**只清消息**，槽位与选中态一律保留。
     pub fn disabled(mut self) -> Self {
         self.on_press = None;
@@ -141,10 +150,10 @@ struct ItemPalette {
     trailing: Color,
 }
 
-fn palette(ui: &Ui, state: Interaction, selected: bool) -> ItemPalette {
+fn palette(ui: &Ui, base: Base, state: Interaction, selected: bool) -> ItemPalette {
     if state.is_disabled() {
         // A1：ListItemDisabled*Color = OnSurface × 0.38（无容器时叠在 surface 上）
-        let ink = interaction::disabled_content_over_role(ui, Role::OnSurface, false);
+        let ink = interaction::disabled_content_over_role(ui, base, Role::OnSurface, false);
         return ItemPalette {
             fill: None,
             headline: ink,
@@ -213,7 +222,12 @@ pub fn list_item<'a, M: Clone + 'a>(ui: &'a Ui, item: ListItem<'a, M>) -> Elemen
     } else {
         None
     });
-    let colors = palette(ui, forced.unwrap_or(Interaction::Enabled), item.selected);
+    let colors = palette(
+        ui,
+        item.base,
+        forced.unwrap_or(Interaction::Enabled),
+        item.selected,
+    );
 
     let mut body = iced::widget::Column::new().spacing(0);
     if let Some(overline) = item.overline {
@@ -268,9 +282,10 @@ pub fn list_item<'a, M: Clone + 'a>(ui: &'a Ui, item: ListItem<'a, M>) -> Elemen
         .align_y(Alignment::Center);
 
     let selected = item.selected;
+    let base = item.base;
     let style = move |_theme: &iced::Theme, status: button::Status| {
         let state = forced.unwrap_or_else(|| Interaction::from_status(status));
-        let colors = palette(ui, state, selected);
+        let colors = palette(ui, base, state, selected);
         button::Style {
             background: colors.fill.map(Background::Color),
             text_color: colors.headline,
diff --git a/crates/app-iced/src/components/navigation/list_item/tests.rs b/crates/app-iced/src/components/navigation/list_item/tests.rs
index b1be068..95e76e4 100644
--- a/crates/app-iced/src/components/navigation/list_item/tests.rs
+++ b/crates/app-iced/src/components/navigation/list_item/tests.rs
@@ -56,14 +56,15 @@ fn disabled_only_clears_the_message() {
 #[test]
 fn disabled_content_uses_on_surface() {
     let ui = ui();
-    let palette = palette(&ui, Interaction::Disabled, false);
-    let expected = interaction::disabled_content_over_role(&ui, Role::OnSurface, false);
+    let palette = palette(&ui, Base::CANVAS, Interaction::Disabled, false);
+    let expected =
+        interaction::disabled_content_over_role(&ui, Base::CANVAS, Role::OnSurface, false);
     assert_eq!(palette.headline, expected);
     assert_eq!(palette.leading, expected);
     assert_eq!(palette.trailing, expected);
     assert_ne!(
         palette.headline,
-        interaction::disabled_content_over_role(&ui, Role::OnSurfaceVariant, false),
+        interaction::disabled_content_over_role(&ui, Base::CANVAS, Role::OnSurfaceVariant, false),
         "走默认的 OnSurfaceVariant 就会偏浅一档（这条钉住 A1 的角色）"
     );
     assert!(palette.fill.is_none(), "禁用不叠状态层容器");
@@ -73,7 +74,7 @@ fn disabled_content_uses_on_surface() {
 #[test]
 fn selected_row_is_secondary_container() {
     let ui = ui();
-    let palette = palette(&ui, Interaction::Enabled, true);
+    let palette = palette(&ui, Base::CANVAS, Interaction::Enabled, true);
     assert_eq!(palette.fill, Some(ui.color(Role::SecondaryContainer)));
     assert_eq!(palette.headline, ui.color(Role::OnSecondaryContainer));
     assert_eq!(palette.trailing, ui.color(Role::Primary), "4.8");
@@ -83,13 +84,13 @@ fn selected_row_is_secondary_container() {
 #[test]
 fn interaction_states_keep_the_content_colors() {
     let ui = ui();
-    let resting = palette(&ui, Interaction::Enabled, false);
+    let resting = palette(&ui, Base::CANVAS, Interaction::Enabled, false);
     for state in [
         Interaction::Hovered,
         Interaction::Focused,
         Interaction::Pressed,
     ] {
-        let active = palette(&ui, state, false);
+        let active = palette(&ui, Base::CANVAS, state, false);
         assert_eq!(active.headline, resting.headline, "{state:?} 不许改文本色");
         assert_eq!(active.leading, resting.leading, "{state:?} 不许改图标色");
         assert!(active.fill.is_some(), "{state:?} 必须叠状态层");
diff --git a/crates/app-iced/src/components/navigation/probe.rs b/crates/app-iced/src/components/navigation/probe.rs
index 68d2730..8767661 100644
--- a/crates/app-iced/src/components/navigation/probe.rs
+++ b/crates/app-iced/src/components/navigation/probe.rs
@@ -127,11 +127,13 @@ fn list_item_rows_are_44_60_76() {
     let darkest = shot.darkest(&disabled).expect("禁用格里应有墨迹");
     let right = rgb(interaction::disabled_content_over_role(
         &ui,
+        interaction::Base::CANVAS,
         Role::OnSurface,
         false,
     ));
     let wrong = rgb(interaction::disabled_content_over_role(
         &ui,
+        interaction::Base::CANVAS,
         Role::OnSurfaceVariant,
         false,
     ));
diff --git a/crates/app-iced/src/components/navigation/tabs.rs b/crates/app-iced/src/components/navigation/tabs.rs
index a89d683..cb80db6 100644
--- a/crates/app-iced/src/components/navigation/tabs.rs
+++ b/crates/app-iced/src/components/navigation/tabs.rs
@@ -50,7 +50,7 @@ use unlucky_design::typography::TypeRole;
 use crate::icons;
 use crate::theme::Ui;
 
-use super::super::interaction::{self, Interaction};
+use super::super::interaction::{self, Base, Interaction};
 use super::super::layout;
 use super::geometry::{TabsGeometry, TABS_ICON_HEIGHT};
 
@@ -133,6 +133,8 @@ impl<'a, M> Tab<'a, M> {
 pub struct Tabs<'a, M> {
     variant: TabsVariant,
     tabs: Vec<Tab<'a, M>>,
+    /// 脚下那一层的底（M234，禁用态合成用）。
+    base: Base,
 }
 
 impl<'a, M> Tabs<'a, M> {
@@ -141,6 +143,7 @@ impl<'a, M> Tabs<'a, M> {
         Self {
             variant: TabsVariant::Primary,
             tabs: Vec::new(),
+            base: Base::CANVAS,
         }
     }
 
@@ -149,6 +152,7 @@ impl<'a, M> Tabs<'a, M> {
         Self {
             variant: TabsVariant::Secondary,
             tabs: Vec::new(),
+            base: Base::CANVAS,
         }
     }
 
@@ -157,14 +161,20 @@ impl<'a, M> Tabs<'a, M> {
         self.tabs.push(tab);
         self
     }
+
+    /// **告诉 tab 条它踩在什么底上**（M234）：禁用态的 38% 标签/指示条叠在这个底上。
+    pub fn base(mut self, base: impl Into<Base>) -> Self {
+        self.base = base.into();
+        self
+    }
 }
 
 /// 一个 tab 的内容色（A1 的 `Active*` / `Inactive*` / 各态表，见模块文档）。
-fn content_color(ui: &Ui, primary: bool, state: Interaction, selected: bool) -> Color {
+fn content_color(ui: &Ui, base: Base, primary: bool, state: Interaction, selected: bool) -> Color {
     if state.is_disabled() {
         // A1 的 Tabs 没有 Disabled* token（实读：Primary/Secondary 两套都只有 Active/Inactive × 四态），
         // 按 ListItem 的 38% 口径处理 —— 登记 `[估]`。
-        return interaction::disabled_content_over_role(ui, Role::OnSurface, false);
+        return interaction::disabled_content_over_role(ui, base, Role::OnSurface, false);
     }
     if selected {
         // 6.5：Primary 选中 `Primary`；Secondary 选中 `OnSurface`
@@ -182,13 +192,14 @@ fn content_color(ui: &Ui, primary: bool, state: Interaction, selected: bool) ->
 }
 
 /// Primary 指示条的颜色（只有选中项有；禁用项降档，否则「点不动却亮着」）。
-fn bar_color(ui: &Ui, state: Interaction, selected: bool) -> Option<Color> {
+fn bar_color(ui: &Ui, base: Base, state: Interaction, selected: bool) -> Option<Color> {
     if !selected {
         return None;
     }
     if state.is_disabled() {
         return Some(interaction::disabled_content_over_role(
             ui,
+            base,
             Role::OnSurface,
             false,
         ));
@@ -207,6 +218,7 @@ fn secondary_line_color(ui: &Ui) -> Color {
 pub fn tabs<'a, M: Clone + 'a>(ui: &'a Ui, tabs: Tabs<'a, M>) -> Element<'a, M> {
     let geometry = TabsGeometry::of(ui);
     let primary = tabs.variant.is_primary();
+    let base = tabs.base;
     // 6.1：带图标时容器高 **64**（`IconAndLabelTextContainerHeight`），纯文字 48
     let height = if tabs.tabs.iter().any(|tab| tab.icon.is_some()) {
         TABS_ICON_HEIGHT
@@ -218,7 +230,7 @@ pub fn tabs<'a, M: Clone + 'a>(ui: &'a Ui, tabs: Tabs<'a, M>) -> Element<'a, M>
         .height(Length::Fixed(height))
         .align_y(Alignment::Center);
     for tab in tabs.tabs {
-        row = row.push(tab_cell(ui, tab, geometry, primary, height));
+        row = row.push(tab_cell(ui, base, tab, geometry, primary, height));
     }
 
     let body: Element<'a, M> = if primary {
@@ -254,8 +266,10 @@ pub fn tabs<'a, M: Clone + 'a>(ui: &'a Ui, tabs: Tabs<'a, M>) -> Element<'a, M>
 }
 
 /// 一个 tab 单元（内容 + 底部条）。
+#[allow(clippy::too_many_arguments)]
 fn tab_cell<'a, M: Clone + 'a>(
     ui: &'a Ui,
+    base: Base,
     tab: Tab<'a, M>,
     geometry: TabsGeometry,
     primary: bool,
@@ -268,7 +282,7 @@ fn tab_cell<'a, M: Clone + 'a>(
     });
     let state = forced.unwrap_or(Interaction::Enabled);
     let selected = tab.selected;
-    let color = content_color(ui, primary, state, selected);
+    let color = content_color(ui, base, primary, state, selected);
     let style = ui.style(TypeRole::TitleSmall);
 
     let label = text(tab.label)
@@ -291,7 +305,7 @@ fn tab_cell<'a, M: Clone + 'a>(
 
     let bar_height = geometry.bar(primary);
     // 底层：内容自己决定宽度（Shrink），底部留出条的高度 —— 未选中的 Primary tab 也占同样的高
-    let base = container(content)
+    let cell = container(content)
         .height(Length::Fixed(height))
         // Q21：要给居中就两轴都显式给（`Container` 默认 Left/Top）
         .align_x(Alignment::Center)
@@ -305,12 +319,12 @@ fn tab_cell<'a, M: Clone + 'a>(
 
     // Primary：逐 tab 画条（要跟随该 tab 的宽度）；Secondary：整行一条，在 `tabs()` 里画
     let bar = if primary {
-        bar_color(ui, state, selected)
+        bar_color(ui, base, state, selected)
     } else {
         None
     };
     let radius = geometry.indicator_radius();
-    let mut stack = Stack::new().push(base);
+    let mut stack = Stack::new().push(cell);
     if let Some(color) = bar {
         // 上层：Fill —— `Stack` 先按底层定尺寸，所以这里的 Fill = 这个 tab 的宽（不是整行）
         stack = stack.push(
@@ -333,7 +347,7 @@ fn tab_cell<'a, M: Clone + 'a>(
         );
     }
 
-    let fill = interaction::overlay_color(ui, state, Role::OnSurface, Role::Surface);
+    let fill = interaction::overlay_color(ui, state, Role::OnSurface, base.role());
     let button = button(stack)
         .height(Length::Fixed(height))
         .padding(0)
diff --git a/crates/app-iced/src/components/navigation/tabs/tests.rs b/crates/app-iced/src/components/navigation/tabs/tests.rs
index 0446961..1029e50 100644
--- a/crates/app-iced/src/components/navigation/tabs/tests.rs
+++ b/crates/app-iced/src/components/navigation/tabs/tests.rs
@@ -7,7 +7,7 @@ use unlucky_design::typography::Platform;
 
 use crate::theme::Families;
 
-use super::super::super::interaction;
+use super::super::super::interaction::{self, Base};
 
 fn ui() -> Ui {
     Ui::with_platform(
@@ -26,16 +26,16 @@ fn ui() -> Ui {
 fn active_colors_follow_the_variant() {
     let ui = ui();
     assert_eq!(
-        content_color(&ui, true, Interaction::Enabled, true),
+        content_color(&ui, Base::CANVAS, true, Interaction::Enabled, true),
         ui.color(Role::Primary)
     );
     assert_eq!(
-        content_color(&ui, false, Interaction::Enabled, true),
+        content_color(&ui, Base::CANVAS, false, Interaction::Enabled, true),
         ui.color(Role::OnSurface),
         "6.5：Secondary 的选中项是 OnSurface"
     );
     assert_ne!(
-        content_color(&ui, false, Interaction::Enabled, true),
+        content_color(&ui, Base::CANVAS, false, Interaction::Enabled, true),
         ui.color(Role::Primary),
         "把 Secondary 的选中色写成 Primary 是最常见的串线"
     );
@@ -47,7 +47,7 @@ fn inactive_states_lift_to_on_surface() {
     let ui = ui();
     for primary in [true, false] {
         assert_eq!(
-            content_color(&ui, primary, Interaction::Enabled, false),
+            content_color(&ui, Base::CANVAS, primary, Interaction::Enabled, false),
             ui.color(Role::OnSurfaceVariant)
         );
         for state in [
@@ -56,7 +56,7 @@ fn inactive_states_lift_to_on_surface() {
             Interaction::Pressed,
         ] {
             assert_eq!(
-                content_color(&ui, primary, state, false),
+                content_color(&ui, Base::CANVAS, primary, state, false),
                 ui.color(Role::OnSurface),
                 "{state:?} 必须提到 OnSurface"
             );
@@ -68,15 +68,19 @@ fn inactive_states_lift_to_on_surface() {
 #[test]
 fn primary_bar_only_on_the_selected_tab() {
     let ui = ui();
-    assert_eq!(bar_color(&ui, Interaction::Enabled, false), None);
     assert_eq!(
-        bar_color(&ui, Interaction::Enabled, true),
+        bar_color(&ui, Base::CANVAS, Interaction::Enabled, false),
+        None
+    );
+    assert_eq!(
+        bar_color(&ui, Base::CANVAS, Interaction::Enabled, true),
         Some(ui.color(Role::Primary))
     );
     assert_eq!(
-        bar_color(&ui, Interaction::Disabled, true),
+        bar_color(&ui, Base::CANVAS, Interaction::Disabled, true),
         Some(interaction::disabled_content_over_role(
             &ui,
+            Base::CANVAS,
             Role::OnSurface,
             false
         )),
diff --git a/crates/app-iced/src/components/selection/checkbox.rs b/crates/app-iced/src/components/selection/checkbox.rs
index 0bea349..4c6b3ba 100644
--- a/crates/app-iced/src/components/selection/checkbox.rs
+++ b/crates/app-iced/src/components/selection/checkbox.rs
@@ -22,7 +22,7 @@ use unlucky_design::typography::TypeRole;
 
 use crate::theme::Ui;
 
-use super::super::interaction::Interaction;
+use super::super::interaction::{Base, Interaction};
 use super::geometry::ControlGeometry;
 use super::paint::{self, Frame};
 use super::shell::{self, StateSource};
@@ -58,6 +58,8 @@ pub struct Checkbox<'a, M> {
     on_toggle: Option<M>,
     error: bool,
     state: Option<Interaction>,
+    /// 脚下那一层的底（M234，禁用态合成用）。
+    base: Base,
 }
 
 impl<'a, M> Checkbox<'a, M> {
@@ -82,6 +84,7 @@ impl<'a, M> Checkbox<'a, M> {
             on_toggle: Some(on_toggle),
             error: false,
             state: None,
+            base: Base::CANVAS,
         }
     }
 
@@ -93,6 +96,7 @@ impl<'a, M> Checkbox<'a, M> {
             on_toggle: None,
             error: false,
             state: None,
+            base: Base::CANVAS,
         }
     }
 
@@ -107,6 +111,12 @@ impl<'a, M> Checkbox<'a, M> {
         self.state = Some(state);
         self
     }
+
+    /// **告诉复选框它踩在什么底上**（M234）：禁用态的 38% 内容/描边叠在这个底上。
+    pub fn base(mut self, base: impl Into<Base>) -> Self {
+        self.base = base.into();
+        self
+    }
 }
 
 /// 画一个复选框（框 + 标签）。
@@ -117,11 +127,12 @@ pub fn checkbox<'a, M: Clone + 'a>(ui: &'a Ui, spec: Checkbox<'a, M>) -> Element
     let error = spec.error;
     let radius = geometry.radius;
     let stroke = geometry.stroke;
+    let base = spec.base;
     let source = StateSource::new(spec.state, spec.on_toggle.is_some());
 
     // 勾的颜色与 hover/pressed 无关（A1：`SelectedHover/Focus/PressedIconColor` 都是 `OnPrimary`），
     // 只随「选中 + 禁用」变 —— 所以这里用**静态**态求值（SVG 的颜色在构建期就要定）。
-    let at_rest = paint::checkbox(ui, filled, error, source.get(), radius, stroke);
+    let at_rest = paint::checkbox(ui, base, filled, error, source.get(), radius, stroke);
     let glyph: Element<'a, M> = if filled {
         shell::square(
             geometry.side,
@@ -136,7 +147,7 @@ pub fn checkbox<'a, M: Clone + 'a>(ui: &'a Ui, spec: Checkbox<'a, M>) -> Element
         .width(Length::Fixed(geometry.side))
         .height(Length::Fixed(geometry.side))
         .style(source.container_style(move |state| {
-            paint::checkbox(ui, filled, error, state, radius, stroke)
+            paint::checkbox(ui, base, filled, error, state, radius, stroke)
                 .frame
                 .container_style()
         }));
@@ -165,7 +176,7 @@ pub fn checkbox<'a, M: Clone + 'a>(ui: &'a Ui, spec: Checkbox<'a, M>) -> Element
             text(spec.label)
                 .size(style.size_px)
                 .font(ui.font_of(style))
-                .color(paint::label(ui, source.get())),
+                .color(paint::label(ui, base, source.get())),
         );
     }
 
diff --git a/crates/app-iced/src/components/selection/chip.rs b/crates/app-iced/src/components/selection/chip.rs
index ba1b8fe..7f3a1a1 100644
--- a/crates/app-iced/src/components/selection/chip.rs
+++ b/crates/app-iced/src/components/selection/chip.rs
@@ -42,7 +42,7 @@ use unlucky_design::typography::TypeRole;
 use crate::icons;
 use crate::theme::Ui;
 
-use super::super::interaction::Interaction;
+use super::super::interaction::{Base, Interaction};
 use super::geometry::ChipGeometry;
 use super::paint::{self, ChipVariant};
 
@@ -58,6 +58,8 @@ pub struct Chip<'a, M> {
     state: Option<Interaction>,
     /// 「当前项」标记（[`Chip::current`]）：选中配色照画，但**不**降成禁用配色、也不吃五态。
     marker: bool,
+    /// 脚下那一层的底（M234，禁用态合成用）。
+    base: Base,
 }
 
 impl<'a, M> Chip<'a, M> {
@@ -94,6 +96,7 @@ impl<'a, M> Chip<'a, M> {
             on_press: None,
             state: None,
             marker: false,
+            base: Base::CANVAS,
         }
     }
 
@@ -116,6 +119,7 @@ impl<'a, M> Chip<'a, M> {
             on_press: None,
             state: None,
             marker: true,
+            base: Base::CANVAS,
         }
     }
 
@@ -140,6 +144,7 @@ impl<'a, M> Chip<'a, M> {
             on_press: Some(on_press),
             state: None,
             marker: false,
+            base: Base::CANVAS,
         }
     }
 
@@ -161,6 +166,12 @@ impl<'a, M> Chip<'a, M> {
         self
     }
 
+    /// **告诉 chip 它踩在什么底上**（M234）：禁用态那 12% 容器/描边与 38% 内容叠在这个底上。
+    pub fn base(mut self, base: impl Into<Base>) -> Self {
+        self.base = base.into();
+        self
+    }
+
     /// 静息时的外观——**唯一**把「这颗 chip 属于哪个档位」翻成颜色的地方。
     ///
     /// `chip()` 用它求文字/图标色，测试也用它量对比度：档位的判据（当前项 / 选中 / 禁用）
@@ -177,7 +188,7 @@ impl<'a, M> Chip<'a, M> {
         } else {
             self.state.unwrap_or(Interaction::Enabled)
         };
-        paint::chip(ui, self.variant, self.selected, state, radius)
+        paint::chip(ui, self.base, self.variant, self.selected, state, radius)
     }
 }
 
@@ -188,6 +199,7 @@ pub fn chip<'a, M: Clone + 'a>(ui: &'a Ui, spec: Chip<'a, M>) -> Element<'a, M>
     let selected = spec.selected;
     let marker = spec.marker;
     let forced = spec.state;
+    let base = spec.base;
 
     // 文字/图标色只看「选中 + 禁用」（A1：Filter/Input 的 label 色在 hover/focus/pressed 不变），
     // 所以这里静态求值；容器（含状态层）在样式闭包里跟态走。档位的判据在 `Chip::paint` 一处
@@ -241,7 +253,7 @@ pub fn chip<'a, M: Clone + 'a>(ui: &'a Ui, spec: Chip<'a, M>) -> Element<'a, M>
                 paint::current_item(ui, geometry.radius)
             } else {
                 let state = forced.unwrap_or_else(|| Interaction::from_status(status));
-                paint::chip(ui, variant, selected, state, geometry.radius)
+                paint::chip(ui, base, variant, selected, state, geometry.radius)
             };
             button::Style {
                 background: paint.frame.fill.map(Background::Color),
diff --git a/crates/app-iced/src/components/selection/paint/check.rs b/crates/app-iced/src/components/selection/paint/check.rs
index 6fdab48..31ca3e4 100644
--- a/crates/app-iced/src/components/selection/paint/check.rs
+++ b/crates/app-iced/src/components/selection/paint/check.rs
@@ -4,7 +4,7 @@ use unlucky_design::color::Role;
 
 use crate::theme::Ui;
 
-use super::super::super::interaction::Interaction;
+use super::super::super::interaction::{Base, Interaction};
 use super::{disabled_ink, lifted, CheckboxPaint, Frame};
 
 /// Checkbox 的外观。
@@ -13,6 +13,7 @@ use super::{disabled_ink, lifted, CheckboxPaint, Frame};
 /// 选中态没有描边（`SelectedOutlineWidth = 0`，走填充分支）。
 pub fn checkbox(
     ui: &Ui,
+    base: Base,
     selected: bool,
     error: bool,
     state: Interaction,
@@ -25,8 +26,8 @@ pub fn checkbox(
                 // A1：`SelectedDisabledContainerColor = OnSurface` +
                 // `SelectedDisabledContainerOpacity = 0.38` —— **不是** 12%（复审 P2-3）。
                 // 与未选中禁用的描边是同一个 38% 叠色，两格看起来才成对。
-                fill: selected.then(|| disabled_ink(ui, Role::OnSurface)),
-                outline: (!selected).then(|| disabled_ink(ui, Role::OnSurface)),
+                fill: selected.then(|| disabled_ink(ui, base, Role::OnSurface)),
+                outline: (!selected).then(|| disabled_ink(ui, base, Role::OnSurface)),
                 stroke,
                 radius,
             },
diff --git a/crates/app-iced/src/components/selection/paint/chip.rs b/crates/app-iced/src/components/selection/paint/chip.rs
index 503ff16..ecab50a 100644
--- a/crates/app-iced/src/components/selection/paint/chip.rs
+++ b/crates/app-iced/src/components/selection/paint/chip.rs
@@ -4,7 +4,7 @@ use unlucky_design::color::Role;
 
 use crate::theme::{Ui, STROKE_PX};
 
-use super::super::super::interaction::Interaction;
+use super::super::super::interaction::{Base, Interaction};
 use super::{disabled_container, disabled_ink, state_layer, ChipPaint, Frame};
 
 /// Chip 的三种（§13.6 / §13.7）：Assist / Filter / Input。
@@ -24,6 +24,7 @@ pub enum ChipVariant {
 /// 所以未选中 + hover 的 fill 是「状态层叠在 surface 上」的实色。
 pub fn chip(
     ui: &Ui,
+    base: Base,
     variant: ChipVariant,
     selected: bool,
     state: Interaction,
@@ -39,11 +40,11 @@ pub fn chip(
     };
 
     if state.is_disabled() {
-        let ink = disabled_ink(ui, Role::OnSurface);
+        let ink = disabled_ink(ui, base, Role::OnSurface);
         return ChipPaint {
             frame: Frame {
-                fill: selected.then(|| disabled_container(ui)),
-                outline: (!selected).then(|| disabled_container(ui)),
+                fill: selected.then(|| disabled_container(ui, base)),
+                outline: (!selected).then(|| disabled_container(ui, base)),
                 stroke: STROKE_PX,
                 radius,
             },
@@ -102,5 +103,12 @@ pub fn chip(
 /// pressed / disabled 五态（见 `Chip::current` 的文档）。对比度下限是 [`crate::components::selection::paint`]
 /// 同一条正文口径（WCAG AA 4.5:1，`unlucky_design::palette::wcag::AA_TEXT`）。
 pub fn current_item(ui: &Ui, radius: f32) -> ChipPaint {
-    chip(ui, ChipVariant::Filter, true, Interaction::Enabled, radius)
+    chip(
+        ui,
+        Base::CANVAS,
+        ChipVariant::Filter,
+        true,
+        Interaction::Enabled,
+        radius,
+    )
 }
diff --git a/crates/app-iced/src/components/selection/paint/mod.rs b/crates/app-iced/src/components/selection/paint/mod.rs
index 648f40a..f9bb5c6 100644
--- a/crates/app-iced/src/components/selection/paint/mod.rs
+++ b/crates/app-iced/src/components/selection/paint/mod.rs
@@ -27,7 +27,7 @@ use unlucky_design::color::Role;
 
 use crate::theme::Ui;
 
-use super::super::interaction::{self, Interaction};
+use super::super::interaction::{self, Base, Interaction};
 
 mod check;
 mod chip;
@@ -115,17 +115,21 @@ pub fn state_layer(ui: &Ui, state: Interaction, content: Role) -> Option<Color>
     interaction::overlay_color(ui, state, content, Role::Surface)
 }
 
-/// `OnSurface`@12% 叠 surface（**容器**禁用色：Switch 轨道、Chip 未选中描边）。
+/// `OnSurface`@12% 叠 `base`（**容器**禁用色：Switch 轨道、Chip 未选中描边）。
+///
+/// `base` 是控件**脚下那一层的底**（M234）：画布 = [`Base::CANVAS`]、卡片 =
+/// `surfaces::elevated::BASE`。M229 之前这里写死 `Role::Surface`，卡片里的禁用 chip
+/// 于是把 12% 叠在画布色上。
 ///
 /// 注意：Checkbox「选中且禁用」的**填充**不是这个 12%，A1 的
 /// `SelectedDisabledContainerOpacity = 0.38` → 见 [`disabled_ink`]（复审 P2-3）。
-pub(super) fn disabled_container(ui: &Ui) -> Color {
-    interaction::disabled_colors(ui, Role::Surface).0
+pub(super) fn disabled_container(ui: &Ui, base: Base) -> Color {
+    interaction::disabled_colors(ui, base).0
 }
 
-/// 内容禁用色：`role` @38% 叠在 surface 上（`on_container = false`）。
-pub(super) fn disabled_ink(ui: &Ui, role: Role) -> Color {
-    interaction::disabled_content_over_role(ui, role, false)
+/// 内容禁用色：`role` @38% 叠在 `base` 上（`on_container = false`）。
+pub(super) fn disabled_ink(ui: &Ui, base: Base, role: Role) -> Color {
+    interaction::disabled_content_over_role(ui, base, role, false)
 }
 
 /// hover / focus / pressed（「抬起来」的三态）。
@@ -140,9 +144,9 @@ pub(super) fn lifted(state: Interaction) -> bool {
 ///
 /// A1 里 checkbox/radio 都没有「标签色随 hover 变」的字段（标签不属于控件本体），
 /// 所以这里只看禁用与否。
-pub fn label(ui: &Ui, state: Interaction) -> Color {
+pub fn label(ui: &Ui, base: Base, state: Interaction) -> Color {
     if state.is_disabled() {
-        disabled_ink(ui, Role::OnSurface)
+        disabled_ink(ui, base, Role::OnSurface)
     } else {
         ui.color(Role::OnSurface)
     }
diff --git a/crates/app-iced/src/components/selection/paint/radio.rs b/crates/app-iced/src/components/selection/paint/radio.rs
index 7d09072..da0112c 100644
--- a/crates/app-iced/src/components/selection/paint/radio.rs
+++ b/crates/app-iced/src/components/selection/paint/radio.rs
@@ -4,15 +4,22 @@ use unlucky_design::color::Role;
 
 use crate::theme::Ui;
 
-use super::super::super::interaction::Interaction;
+use super::super::super::interaction::{Base, Interaction};
 use super::{disabled_ink, lifted, Frame, RadioPaint};
 
 /// Radio 的外观。
 ///
 /// **选中态 hover 不换色**：环与点在四态里都是 `Primary`（只有状态层变）。
-pub fn radio(ui: &Ui, selected: bool, state: Interaction, radius: f32, stroke: f32) -> RadioPaint {
+pub fn radio(
+    ui: &Ui,
+    base: Base,
+    selected: bool,
+    state: Interaction,
+    radius: f32,
+    stroke: f32,
+) -> RadioPaint {
     let ink = if state.is_disabled() {
-        disabled_ink(ui, Role::OnSurface)
+        disabled_ink(ui, base, Role::OnSurface)
     } else if selected {
         ui.color(Role::Primary)
     } else if lifted(state) {
diff --git a/crates/app-iced/src/components/selection/paint/switch.rs b/crates/app-iced/src/components/selection/paint/switch.rs
index d4b2520..5c905c5 100644
--- a/crates/app-iced/src/components/selection/paint/switch.rs
+++ b/crates/app-iced/src/components/selection/paint/switch.rs
@@ -7,17 +7,17 @@ use unlucky_design::shape::ShapeScale;
 
 use crate::theme::Ui;
 
-use super::super::super::interaction::{self, Interaction};
+use super::super::super::interaction::{self, Base, Interaction};
 use super::super::geometry::SwitchGeometry;
 use super::{disabled_container, disabled_ink, lifted, Frame, SwitchPaint};
 
 /// Switch 的外观。
-pub fn switch(ui: &Ui, selected: bool, state: Interaction) -> SwitchPaint {
+pub fn switch(ui: &Ui, base: Base, selected: bool, state: Interaction) -> SwitchPaint {
     let geometry = SwitchGeometry::of(ui);
     let radius = ShapeScale::Full.radius_px(geometry.track_height);
 
     if state.is_disabled() {
-        let container = disabled_container(ui);
+        let container = disabled_container(ui, base);
         return if selected {
             SwitchPaint {
                 track: Frame {
@@ -28,7 +28,7 @@ pub fn switch(ui: &Ui, selected: bool, state: Interaction) -> SwitchPaint {
                 },
                 // `DisabledSelectedHandleColor = Surface` 且不透明度 1（A1 的 fconst_1）
                 thumb: ui.color(Role::Surface),
-                icon: Some(disabled_ink(ui, Role::OnSurface)),
+                icon: Some(disabled_ink(ui, base, Role::OnSurface)),
             }
         } else {
             SwitchPaint {
@@ -38,7 +38,7 @@ pub fn switch(ui: &Ui, selected: bool, state: Interaction) -> SwitchPaint {
                     stroke: geometry.track_stroke,
                     radius,
                 },
-                thumb: disabled_ink(ui, Role::OnSurface),
+                thumb: disabled_ink(ui, base, Role::OnSurface),
                 icon: None,
             }
         };
diff --git a/crates/app-iced/src/components/selection/probe.rs b/crates/app-iced/src/components/selection/probe.rs
index a10ac73..96ac5b8 100644
--- a/crates/app-iced/src/components/selection/probe.rs
+++ b/crates/app-iced/src/components/selection/probe.rs
@@ -25,7 +25,7 @@
 use unlucky_design::color::{Role, SchemeFlavor};
 use unlucky_design::typography::Platform;
 
-use super::super::interaction::{self, Interaction};
+use super::super::interaction::{self, Base, Interaction};
 use super::pixel::{center, dims, ink_boxes, inner_ink, matches, near, rgb, shot_path, Shot};
 use crate::theme::{Families, Ui};
 
@@ -273,7 +273,7 @@ fn selection_geometry_matches_the_reference() {
     // 判据：禁用列里必须**恰好有一块** 12% 填充的 chip（= filter·on）。旧 API 把 selected
     // 一起删掉，这一块根本不存在（实测 0 块）；能查到它、且宽度 ≥58，说明选中态与图标都还在。
     // （未选中的那三个禁用 chip 只有 1px 描边，落在半像素上时覆盖率不足 50%，量不稳，故不在此断言。）
-    let disabled_container = interaction::disabled_colors(&ui, Role::Surface).0;
+    let disabled_container = interaction::disabled_colors(&ui, Base::CANVAS).0;
     let disabled_chips: Vec<_> = ink_boxes(&shot, disabled_container, surface, 28, 140)
         .into_iter()
         .filter(|bbox| near(bbox.height(), 32) && bbox.width() >= 58)
@@ -292,7 +292,8 @@ fn selection_geometry_matches_the_reference() {
     );
 
     // ---- 复审 P2-3：**选中且禁用**的 Checkbox 容器是 38%，不是 12% -----------------
-    let disabled_ink = interaction::disabled_content_over_role(&ui, Role::OnSurface, false);
+    let disabled_ink =
+        interaction::disabled_content_over_role(&ui, Base::CANVAS, Role::OnSurface, false);
     let ink38: Vec<_> = ink_boxes(&shot, disabled_ink, surface, 17, 24)
         .into_iter()
         .filter(|bbox| near(bbox.width(), 20) && near(bbox.height(), 20))
diff --git a/crates/app-iced/src/components/selection/radio.rs b/crates/app-iced/src/components/selection/radio.rs
index aa026ba..86f079f 100644
--- a/crates/app-iced/src/components/selection/radio.rs
+++ b/crates/app-iced/src/components/selection/radio.rs
@@ -22,7 +22,7 @@ use unlucky_design::typography::TypeRole;
 
 use crate::theme::Ui;
 
-use super::super::interaction::Interaction;
+use super::super::interaction::{Base, Interaction};
 use super::geometry::ControlGeometry;
 use super::paint::{self, Frame};
 use super::shell::{self, StateSource};
@@ -34,6 +34,8 @@ pub struct Radio<'a, M> {
     selected: bool,
     on_select: Option<M>,
     state: Option<Interaction>,
+    /// 脚下那一层的底（M234，禁用态合成用）。
+    base: Base,
 }
 
 impl<'a, M> Radio<'a, M> {
@@ -44,6 +46,7 @@ impl<'a, M> Radio<'a, M> {
             selected,
             on_select: Some(on_select),
             state: None,
+            base: Base::CANVAS,
         }
     }
 
@@ -54,6 +57,7 @@ impl<'a, M> Radio<'a, M> {
             selected,
             on_select: None,
             state: None,
+            base: Base::CANVAS,
         }
     }
 
@@ -62,6 +66,12 @@ impl<'a, M> Radio<'a, M> {
         self.state = Some(state);
         self
     }
+
+    /// **告诉单选框它踩在什么底上**（M234）：禁用态的 38% 环/内点叠在这个底上。
+    pub fn base(mut self, base: impl Into<Base>) -> Self {
+        self.base = base.into();
+        self
+    }
 }
 
 /// 画一个单选框（环 + 内点 + 标签）。
@@ -71,11 +81,12 @@ pub fn radio<'a, M: Clone + 'a>(ui: &'a Ui, spec: Radio<'a, M>) -> Element<'a, M
     let radius = geometry.radius;
     let stroke = geometry.stroke;
     let dot_side = geometry.inner_dot;
+    let base = spec.base;
     let source = StateSource::new(spec.state, spec.on_select.is_some());
 
     // 内点与环的颜色与 hover/pressed 无关（A1：选中态四态都是 `Primary`），
     // 只随「选中 + 禁用」变 —— 所以点的颜色在这里静态求值即可。
-    let at_rest = paint::radio(ui, selected, source.get(), radius, stroke);
+    let at_rest = paint::radio(ui, base, selected, source.get(), radius, stroke);
 
     // Ø10 内点（半径 = 直径/2）
     let dot: Element<'a, M> = match at_rest.dot {
@@ -102,7 +113,7 @@ pub fn radio<'a, M: Clone + 'a>(ui: &'a Ui, spec: Radio<'a, M>) -> Element<'a, M
         .align_x(Alignment::Center)
         .align_y(Alignment::Center)
         .style(source.container_style(move |state| {
-            paint::radio(ui, selected, state, radius, stroke)
+            paint::radio(ui, base, selected, state, radius, stroke)
                 .ring
                 .container_style()
         }));
@@ -131,7 +142,7 @@ pub fn radio<'a, M: Clone + 'a>(ui: &'a Ui, spec: Radio<'a, M>) -> Element<'a, M
             text(spec.label)
                 .size(style.size_px)
                 .font(ui.font_of(style))
-                .color(paint::label(ui, source.get())),
+                .color(paint::label(ui, base, source.get())),
         );
     }
 
diff --git a/crates/app-iced/src/components/selection/switch.rs b/crates/app-iced/src/components/selection/switch.rs
index b097cda..3dcec5b 100644
--- a/crates/app-iced/src/components/selection/switch.rs
+++ b/crates/app-iced/src/components/selection/switch.rs
@@ -24,7 +24,7 @@ use unlucky_design::typography::TypeRole;
 use crate::icons;
 use crate::theme::Ui;
 
-use super::super::interaction::Interaction;
+use super::super::interaction::{Base, Interaction};
 use super::geometry::SwitchGeometry;
 use super::paint::{self, Frame};
 use super::shell::{self, StateSource};
@@ -36,6 +36,8 @@ pub struct Switch<'a, M> {
     value: bool,
     on_toggle: Option<M>,
     state: Option<Interaction>,
+    /// 脚下那一层的底（M234，禁用态合成用）。
+    base: Base,
 }
 
 impl<'a, M> Switch<'a, M> {
@@ -46,6 +48,7 @@ impl<'a, M> Switch<'a, M> {
             value,
             on_toggle: Some(on_toggle),
             state: None,
+            base: Base::CANVAS,
         }
     }
 
@@ -56,6 +59,7 @@ impl<'a, M> Switch<'a, M> {
             value,
             on_toggle: None,
             state: None,
+            base: Base::CANVAS,
         }
     }
 
@@ -64,6 +68,12 @@ impl<'a, M> Switch<'a, M> {
         self.state = Some(state);
         self
     }
+
+    /// **告诉开关它踩在什么底上**（M234）：禁用态的 12% 轨道 / 38% 滑块叠在这个底上。
+    pub fn base(mut self, base: impl Into<Base>) -> Self {
+        self.base = base.into();
+        self
+    }
 }
 
 /// 画一个开关（轨道 + 滑块 + 标签）。
@@ -71,11 +81,12 @@ pub fn switch<'a, M: Clone + 'a>(ui: &'a Ui, spec: Switch<'a, M>) -> Element<'a,
     let geometry = SwitchGeometry::of(ui);
     let selected = spec.value;
     let thumb_side = geometry.thumb(selected, false);
+    let base = spec.base;
     let source = StateSource::new(spec.state, spec.on_toggle.is_some());
 
     // 滑块内的勾：颜色只随选中/禁用变（A1 的 `Selected*IconColor` 都是 `OnPrimaryContainer`），
     // 所以静态求值；未选中态官方图标色 = 轨道色（画了也看不见），因此不画。
-    let at_rest = paint::switch(ui, selected, source.get());
+    let at_rest = paint::switch(ui, base, selected, source.get());
     let glyph: Element<'a, M> = match at_rest.icon {
         Some(ink) => super::super::layout::centered_fixed(
             geometry.icon,
@@ -94,7 +105,7 @@ pub fn switch<'a, M: Clone + 'a>(ui: &'a Ui, spec: Switch<'a, M>) -> Element<'a,
         .align_y(Alignment::Center)
         .style(source.container_style(move |state| {
             Frame {
-                fill: Some(paint::switch(ui, selected, state).thumb),
+                fill: Some(paint::switch(ui, base, selected, state).thumb),
                 outline: None,
                 stroke: 0.0,
                 radius: thumb_side / 2.0,
@@ -124,7 +135,9 @@ pub fn switch<'a, M: Clone + 'a>(ui: &'a Ui, spec: Switch<'a, M>) -> Element<'a,
         .width(Length::Fixed(geometry.track_width))
         .height(Length::Fixed(geometry.track_height))
         .style(source.container_style(move |state| {
-            paint::switch(ui, selected, state).track.container_style()
+            paint::switch(ui, base, selected, state)
+                .track
+                .container_style()
         }));
 
     // 绘制区 = 轨道 + 状态层外扩；两层叠放（层序：轨道在下，滑块与状态层在上）
@@ -159,7 +172,7 @@ pub fn switch<'a, M: Clone + 'a>(ui: &'a Ui, spec: Switch<'a, M>) -> Element<'a,
             text(spec.label)
                 .size(style.size_px)
                 .font(ui.font_of(style))
-                .color(paint::label(ui, source.get())),
+                .color(paint::label(ui, base, source.get())),
         );
     }
 
diff --git a/crates/app-iced/src/components/selection/tests.rs b/crates/app-iced/src/components/selection/tests.rs
index 6eed39b..591726a 100644
--- a/crates/app-iced/src/components/selection/tests.rs
+++ b/crates/app-iced/src/components/selection/tests.rs
@@ -6,7 +6,9 @@
 use unlucky_design::color::{Role, SchemeFlavor};
 use unlucky_design::typography::Platform;
 
-use super::super::interaction::{self, Interaction};
+use super::super::interaction::{self, Base, Interaction};
+
+mod chip;
 use super::geometry::{ChipGeometry, ControlGeometry, SwitchGeometry};
 use super::paint::{self, ChipVariant};
 use crate::theme::{Families, Ui};
@@ -156,7 +158,15 @@ fn chip_geometry_matches_the_tokens() {
 fn checkbox_unselected_lifts_the_outline_to_on_surface() {
     let ui = ui();
     let g = ControlGeometry::checkbox(&ui);
-    let at_rest = paint::checkbox(&ui, false, false, Interaction::Enabled, g.radius, g.stroke);
+    let at_rest = paint::checkbox(
+        &ui,
+        Base::CANVAS,
+        false,
+        false,
+        Interaction::Enabled,
+        g.radius,
+        g.stroke,
+    );
     assert_eq!(
         at_rest.frame.outline,
         Some(ui.color(Role::OnSurfaceVariant))
@@ -166,7 +176,7 @@ fn checkbox_unselected_lifts_the_outline_to_on_surface() {
         Interaction::Focused,
         Interaction::Pressed,
     ] {
-        let lifted = paint::checkbox(&ui, false, false, state, g.radius, g.stroke);
+        let lifted = paint::checkbox(&ui, Base::CANVAS, false, false, state, g.radius, g.stroke);
         assert_eq!(
             lifted.frame.outline,
             Some(ui.color(Role::OnSurface)),
@@ -175,7 +185,15 @@ fn checkbox_unselected_lifts_the_outline_to_on_surface() {
         assert_eq!(lifted.frame.stroke, 2.0, "18.8：描边宽度不随态变");
     }
     // 错误态优先于 hover
-    let error = paint::checkbox(&ui, false, true, Interaction::Hovered, g.radius, g.stroke);
+    let error = paint::checkbox(
+        &ui,
+        Base::CANVAS,
+        false,
+        true,
+        Interaction::Hovered,
+        g.radius,
+        g.stroke,
+    );
     assert_eq!(error.frame.outline, Some(ui.color(Role::Error)));
 }
 
@@ -184,7 +202,15 @@ fn checkbox_unselected_lifts_the_outline_to_on_surface() {
 fn checkbox_disabled_keeps_the_stroke_and_uses_the_a1_roles() {
     let ui = ui();
     let g = ControlGeometry::checkbox(&ui);
-    let unchecked = paint::checkbox(&ui, false, false, Interaction::Disabled, g.radius, g.stroke);
+    let unchecked = paint::checkbox(
+        &ui,
+        Base::CANVAS,
+        false,
+        false,
+        Interaction::Disabled,
+        g.radius,
+        g.stroke,
+    );
     assert_eq!(unchecked.frame.stroke, 2.0, "18.8：禁用描边仍 2px");
     assert_eq!(unchecked.frame.fill, None, "18.8：未选中禁用内部仍透明");
     assert!(
@@ -195,7 +221,15 @@ fn checkbox_disabled_keeps_the_stroke_and_uses_the_a1_roles() {
         "18.8：禁用描边是 OnSurface@38%，不是满档角色色"
     );
 
-    let checked = paint::checkbox(&ui, true, false, Interaction::Disabled, g.radius, g.stroke);
+    let checked = paint::checkbox(
+        &ui,
+        Base::CANVAS,
+        true,
+        false,
+        Interaction::Disabled,
+        g.radius,
+        g.stroke,
+    );
     assert_eq!(
         checked.glyph,
         ui.color(Role::Surface),
@@ -203,8 +237,8 @@ fn checkbox_disabled_keeps_the_stroke_and_uses_the_a1_roles() {
     );
     // 复审 P2-3：**选中且禁用**的填充是 OnSurface@38%（`SelectedDisabledContainerOpacity`），
     // 不是普通禁用容器的 12%。两格差一眼就能看出来，所以逐字钉住。
-    let ink38 = interaction::disabled_content_over_role(&ui, Role::OnSurface, false);
-    let container12 = interaction::disabled_colors(&ui, Role::Surface).0;
+    let ink38 = interaction::disabled_content_over_role(&ui, Base::CANVAS, Role::OnSurface, false);
+    let container12 = interaction::disabled_colors(&ui, Base::CANVAS).0;
     assert_eq!(
         checked.frame.fill,
         Some(ink38),
@@ -232,7 +266,7 @@ fn radio_keeps_primary_on_hover_when_selected() {
         if state.is_disabled() {
             continue;
         }
-        let paint = paint::radio(&ui, true, state, g.radius, g.stroke);
+        let paint = paint::radio(&ui, Base::CANVAS, true, state, g.radius, g.stroke);
         assert_eq!(
             paint.ring.outline, primary,
             "19.4：{state:?} 环仍是 Primary"
@@ -240,10 +274,24 @@ fn radio_keeps_primary_on_hover_when_selected() {
         assert_eq!(paint.dot, primary, "19.4：{state:?} 点仍是 Primary");
     }
     // 未选中：静息 OnSurfaceVariant → hover/focus/pressed 提到 OnSurface
-    let at_rest = paint::radio(&ui, false, Interaction::Enabled, g.radius, g.stroke);
+    let at_rest = paint::radio(
+        &ui,
+        Base::CANVAS,
+        false,
+        Interaction::Enabled,
+        g.radius,
+        g.stroke,
+    );
     assert_eq!(at_rest.dot, None, "未选中不画内点");
     assert_eq!(at_rest.ring.outline, Some(ui.color(Role::OnSurfaceVariant)));
-    let lifted = paint::radio(&ui, false, Interaction::Hovered, g.radius, g.stroke);
+    let lifted = paint::radio(
+        &ui,
+        Base::CANVAS,
+        false,
+        Interaction::Hovered,
+        g.radius,
+        g.stroke,
+    );
     assert_eq!(lifted.ring.outline, Some(ui.color(Role::OnSurface)));
 }
 
@@ -251,12 +299,12 @@ fn radio_keeps_primary_on_hover_when_selected() {
 #[test]
 fn switch_handle_roles_follow_the_tokens() {
     let ui = ui();
-    let at_rest = paint::switch(&ui, true, Interaction::Enabled);
+    let at_rest = paint::switch(&ui, Base::CANVAS, true, Interaction::Enabled);
     assert_eq!(at_rest.track.fill, Some(ui.color(Role::Primary)));
     assert_eq!(at_rest.thumb, ui.color(Role::OnPrimary));
     assert_eq!(at_rest.icon, Some(ui.color(Role::OnPrimaryContainer)));
 
-    let hovered = paint::switch(&ui, true, Interaction::Hovered);
+    let hovered = paint::switch(&ui, Base::CANVAS, true, Interaction::Hovered);
     assert_eq!(
         hovered.thumb,
         ui.color(Role::PrimaryContainer),
@@ -268,7 +316,7 @@ fn switch_handle_roles_follow_the_tokens() {
         "轨道不随 hover 变"
     );
 
-    let off = paint::switch(&ui, false, Interaction::Enabled);
+    let off = paint::switch(&ui, Base::CANVAS, false, Interaction::Enabled);
     assert_eq!(
         off.track.outline,
         Some(ui.color(Role::Outline)),
@@ -282,79 +330,10 @@ fn switch_handle_roles_follow_the_tokens() {
     );
     assert_eq!(off.icon, None, "未选中态图标与轨道同色（不画）");
 
-    let disabled = paint::switch(&ui, true, Interaction::Disabled);
+    let disabled = paint::switch(&ui, Base::CANVAS, true, Interaction::Disabled);
     assert_eq!(
         disabled.thumb,
         ui.color(Role::Surface),
         "A1：DisabledSelectedHandleColor=Surface"
     );
 }
-
-/// §13.5 / §13.6 / §13.7：选中态**无描边**、Assist 不可选中、禁用文字 @38%。
-#[test]
-fn chip_roles_follow_the_tokens() {
-    let ui = ui();
-    let radius = ChipGeometry::of(&ui).radius;
-
-    let selected = paint::chip(&ui, ChipVariant::Filter, true, Interaction::Enabled, radius);
-    assert_eq!(
-        selected.frame.fill,
-        Some(ui.color(Role::SecondaryContainer))
-    );
-    assert_eq!(selected.frame.outline, None, "13.5：选中描边 0dp");
-    assert_eq!(selected.label, ui.color(Role::OnSecondaryContainer));
-
-    let unselected = paint::chip(
-        &ui,
-        ChipVariant::Filter,
-        false,
-        Interaction::Enabled,
-        radius,
-    );
-    assert_eq!(
-        unselected.frame.outline,
-        Some(ui.color(Role::OutlineVariant))
-    );
-    assert_eq!(unselected.label, ui.color(Role::OnSurfaceVariant));
-
-    // Assist 没有选中态：即使传 selected = true 也不会变 SecondaryContainer
-    let assist = paint::chip(&ui, ChipVariant::Assist, true, Interaction::Enabled, radius);
-    assert_ne!(assist.frame.fill, Some(ui.color(Role::SecondaryContainer)));
-    assert_eq!(
-        assist.icon,
-        ui.color(Role::Primary),
-        "13.4：Assist 前置图标 Primary"
-    );
-
-    let disabled = paint::chip(
-        &ui,
-        ChipVariant::Filter,
-        false,
-        Interaction::Disabled,
-        radius,
-    );
-    assert_ne!(disabled.label, unselected.label, "13.7：禁用文字降到 38%");
-}
-
-/// 状态层只在三态存在，且**不是**满档角色色（α 由 `interaction` 给）。
-#[test]
-fn state_layer_only_exists_on_lifted_states() {
-    let ui = ui();
-    for (state, expected) in [
-        (Interaction::Enabled, false),
-        (Interaction::Hovered, true),
-        (Interaction::Focused, true),
-        (Interaction::Pressed, true),
-        (Interaction::Disabled, false),
-    ] {
-        let layer = paint::state_layer(&ui, state, Role::OnSurfaceVariant);
-        assert_eq!(layer.is_some(), expected, "{state:?} 的状态层有无");
-        if let Some(color) = layer {
-            assert_eq!(color.a, 1.0, "状态层必须是实色（D27：CPU/GPU 一致）");
-        }
-    }
-    // 同态下 hover 比 pressed 浅（8% < 10%）
-    let hover = paint::state_layer(&ui, Interaction::Hovered, Role::OnSurface).unwrap();
-    let pressed = paint::state_layer(&ui, Interaction::Pressed, Role::OnSurface).unwrap();
-    assert_ne!(hover, pressed);
-}
diff --git a/crates/app-iced/src/components/selection/tests/chip.rs b/crates/app-iced/src/components/selection/tests/chip.rs
new file mode 100644
index 0000000..b5b758b
--- /dev/null
+++ b/crates/app-iced/src/components/selection/tests/chip.rs
@@ -0,0 +1,90 @@
+//! Chip 角色与状态层的单测（M234 从 `selection/tests.rs` 纯搬移，守 400 行硬线）。
+//!
+//! 搬移零改动：判据与注释一字未动，只是**换文件**（`tests.rs` 加了 `.base(..)` 之后到 422 行）。
+
+use super::*;
+
+/// §13.5 / §13.6 / §13.7：选中态**无描边**、Assist 不可选中、禁用文字 @38%。
+#[test]
+fn chip_roles_follow_the_tokens() {
+    let ui = ui();
+    let radius = ChipGeometry::of(&ui).radius;
+
+    let selected = paint::chip(
+        &ui,
+        Base::CANVAS,
+        ChipVariant::Filter,
+        true,
+        Interaction::Enabled,
+        radius,
+    );
+    assert_eq!(
+        selected.frame.fill,
+        Some(ui.color(Role::SecondaryContainer))
+    );
+    assert_eq!(selected.frame.outline, None, "13.5：选中描边 0dp");
+    assert_eq!(selected.label, ui.color(Role::OnSecondaryContainer));
+
+    let unselected = paint::chip(
+        &ui,
+        Base::CANVAS,
+        ChipVariant::Filter,
+        false,
+        Interaction::Enabled,
+        radius,
+    );
+    assert_eq!(
+        unselected.frame.outline,
+        Some(ui.color(Role::OutlineVariant))
+    );
+    assert_eq!(unselected.label, ui.color(Role::OnSurfaceVariant));
+
+    // Assist 没有选中态：即使传 selected = true 也不会变 SecondaryContainer
+    let assist = paint::chip(
+        &ui,
+        Base::CANVAS,
+        ChipVariant::Assist,
+        true,
+        Interaction::Enabled,
+        radius,
+    );
+    assert_ne!(assist.frame.fill, Some(ui.color(Role::SecondaryContainer)));
+    assert_eq!(
+        assist.icon,
+        ui.color(Role::Primary),
+        "13.4：Assist 前置图标 Primary"
+    );
+
+    let disabled = paint::chip(
+        &ui,
+        Base::CANVAS,
+        ChipVariant::Filter,
+        false,
+        Interaction::Disabled,
+        radius,
+    );
+    assert_ne!(disabled.label, unselected.label, "13.7：禁用文字降到 38%");
+}
+
+/// 状态层只在三态存在，且**不是**满档角色色（α 由 `interaction` 给）。
+#[test]
+fn state_layer_only_exists_on_lifted_states() {
+    let ui = ui();
+    for (state, expected) in [
+        (Interaction::Enabled, false),
+        (Interaction::Hovered, true),
+        (Interaction::Focused, true),
+        (Interaction::Pressed, true),
+        (Interaction::Disabled, false),
+    ] {
+        let layer = paint::state_layer(&ui, state, Role::OnSurfaceVariant);
+        assert_eq!(layer.is_some(), expected, "{state:?} 的状态层有无");
+        if let Some(color) = layer {
+            assert_eq!(color.a, 1.0, "状态层必须是实色（D27：CPU/GPU 一致）");
+        }
+    }
+    // 同态下 hover 比 pressed 浅（8% < 10%）
+    let hover = paint::state_layer(&ui, Interaction::Hovered, Role::OnSurface).unwrap();
+    let pressed = paint::state_layer(&ui, Interaction::Pressed, Role::OnSurface).unwrap();
+    assert_ne!(hover, pressed);
+}
diff --git a/crates/app-iced/src/components/surfaces/elevated.rs b/crates/app-iced/src/components/surfaces/elevated.rs
index 33e0391..54a59d1 100644
--- a/crates/app-iced/src/components/surfaces/elevated.rs
+++ b/crates/app-iced/src/components/surfaces/elevated.rs
@@ -31,6 +31,15 @@ use unlucky_design::typography::{TypeRole, TypeStyle, Weight};
 
 use crate::theme::Ui;
 
+use super::super::interaction::Base;
+
+/// 卡片的底（**这个容器画什么，子控件的禁用态就叠什么**）。
+///
+/// 卡内控件的禁用色必须拿这个常量，不许自己写 `Role::Surface`：M234 之前 8 个调用点全传
+/// 画布色，卡片里的禁用按钮于是把 10% 叠在画布上（M223 的「CR 1.05、形丢失」）。
+/// 与 [`card`] 的 `background` 用同一个 `Role`，改色不会漂。
+pub const BASE: Base = Base::of(Role::SurfaceContainer);
+
 /// ELEVATED CARD 的内边距：**20**（= `LayoutMetrics::card_padding`）。
 ///
 /// 为什么不是规格卡量到的 **24**（卡片文字 `x=88` − 框 `x=64`）：本组件唯一的消费者是实例页的
@@ -63,7 +72,8 @@ pub fn card<'a, M: 'a>(ui: &'a Ui, content: impl Into<Element<'a, M>>) -> Elemen
         .style(move |_theme| container::Style {
             // 规格卡的卡底是 **surface-container**（不是 `surface-container-low`）：
             // 层级靠与画布（`surface`）的 tone 差表达，不靠描边。
-            background: Some(Background::Color(ui.color(Role::SurfaceContainer))),
+            // 子控件的禁用态拿同一个角色（[`BASE`]）合成，两边不会漂。
+            background: Some(Background::Color(ui.color(BASE.role()))),
             border: Border {
                 radius: ui.radius_dp(shape),
                 ..Border::default()
diff --git a/crates/app-iced/src/pages/settings/java/tests/marker.rs b/crates/app-iced/src/pages/settings/java/tests/marker.rs
index cb91b73..0902830 100644
--- a/crates/app-iced/src/pages/settings/java/tests/marker.rs
+++ b/crates/app-iced/src/pages/settings/java/tests/marker.rs
@@ -178,7 +178,8 @@ fn the_disabled_chip_still_looks_disabled() {
         let disabled = Chip::<()>::filter("安装", true, ()).disabled().paint(ui);
         let marker = Chip::<()>::current("默认").paint(ui);
 
-        let ink38 = interaction::disabled_content_over_role(ui, Role::OnSurface, false);
+        let ink38 =
+            interaction::disabled_content_over_role(ui, Role::Surface, Role::OnSurface, false);
         let container12 = interaction::disabled_colors(ui, Role::Surface).0;
 
         assert_eq!(