diff --git a/hello b/hello
index c63acbc..d07d3df 100755
Binary files a/hello and b/hello differ
diff --git a/hello.c b/hello.c
index 4d4e87c..aa02370 100644
--- a/hello.c
+++ b/hello.c
@@ -140,6 +140,31 @@ static meow_widget *g_dlc;  static rect_t r_list;   /* LazyColumn */
 static meow_dialog *g_dlg;
 static meow_sheet  *g_sheet;
 
+/* ---- demo 分区标题/slider 值文本：注册为 CUSTOM 绘制物（§6.2 区域重画会重画它们）----
+ * 显式 z=D_TITLE_Z：> 一切自动 z(=127)、< chrome 置顶(999)，故「内容→标题→slider值→chrome」。
+ * 非控件直绘必须注册，否则 meow_ui_invalidate 清底后会漏画（非保留模型固有代价）。 */
+#define D_TITLE_Z 128
+static int g_dtitle_cid[D_TITLE_MAX];   /* 分区标题绘制物 id（rebuild 时注销/重注册） */
+static int g_slider_cid = 0;            /* slider 值文本绘制物 id */
+
+/* CUSTOM 绘制回调：分区标题（ctx=title 下标，指向 g_dtitle[i]） */
+static void demo_draw_title(void *ctx)
+{
+    int i = (int)(intptr_t)ctx;
+    if (i < 0 || i >= g_dtitle_n) return;
+    const meow_theme *th = meow_theme_get();
+    meow_ui_text(g_dtitle[i].x, g_dtitle[i].y, g_dtitle[i].s, 20, th->primary);
+}
+/* CUSTOM 绘制回调：slider 当前值文本（bbox=r_slider_txt） */
+static void demo_draw_slider_val(void *ctx)
+{
+    (void)ctx;
+    if (!g_dslider) return;
+    const meow_theme *th = meow_theme_get();
+    char buf[28]; snprintf(buf, sizeof buf, "slider = %d", meow_slider_get(g_dslider));
+    meow_ui_text(r_slider_txt.x, r_slider_txt.y, buf, 20, th->dim);
+}
+
 /* 前向声明 */
 static void redraw(void);
 static void demo_rebuild_to(int scroll);
@@ -218,8 +243,16 @@ static void d_slot(meow_widget *w, rect_t r)
 }
 static void d_title(int x, int y, const char *s)
 {
-    if (g_dtitle_n < D_TITLE_MAX) { g_dtitle[g_dtitle_n].x = x; g_dtitle[g_dtitle_n].y = y;
-                                    g_dtitle[g_dtitle_n].s = s; g_dtitle_n++; }
+    if (g_dtitle_n < D_TITLE_MAX) {
+        int i = g_dtitle_n;
+        g_dtitle[i].x = x; g_dtitle[i].y = y; g_dtitle[i].s = s;
+        g_dtitle_n++;
+        /* 注册为 CUSTOM 绘制物（bbox=文本绘制范围；cb 读 g_dtitle[i]） */
+        int tw = meow_ui_text_width(s, 20);
+        int th = meow_ui_text_height(20);
+        g_dtitle_cid[i] = meow_draw_custom_register(D_TITLE_Z, x, y, tw, th,
+                                                    demo_draw_title, (void *)(intptr_t)i);
+    }
 }
 
 /* LazyColumn 数据源（100 项虚拟化） */
@@ -231,12 +264,15 @@ static int demo_list_src(int idx, char *label, int len, void *ctx)
     return 1;
 }
 
-/* 释放当前全部内容控件（含 Card 的独立子按钮）；chrome 不在其列。 */
+/* 释放当前全部内容控件（含 Card 的独立子按钮）与 CUSTOM 绘制物；chrome 不在其列。 */
 static void demo_free_content(void)
 {
     for (int i = 0; i < g_dslot_n; i++) meow_widget_free(g_dslot[i].w);
     g_dslot_n = 0;
     if (g_dcard_btn) { meow_widget_free(g_dcard_btn); g_dcard_btn = NULL; }
+    for (int i = 0; i < g_dtitle_n; i++)
+        if (g_dtitle_cid[i] > 0) { meow_draw_unregister(g_dtitle_cid[i]); g_dtitle_cid[i] = 0; }
+    if (g_slider_cid > 0) { meow_draw_unregister(g_slider_cid); g_slider_cid = 0; }
     g_dtitle_n = 0;
 }
 
@@ -272,8 +308,11 @@ static void demo_build_at(int scroll)
     d_title(DCL_X, SY(yb), "INPUT & STATE"); yb += 26;
     r_dsw = RX(DCL_X, SY(yb), 56, 32); g_dsw = meow_switch_create(r_dsw.x, r_dsw.y, g_ds.sw_on); SLOT(g_dsw, r_dsw.x, r_dsw.y, r_dsw.w, r_dsw.h); yb += 44;
 
-    r_slider_txt = RX(DCL_X, SY(yb), 100, 24); yb += 24;
+    r_slider_txt = RX(DCL_X, SY(yb), 160, 24); yb += 24;   /* 加宽到覆盖值文本全宽（防局部刷漏尾） */
     r_slider = RX(DCL_X, SY(yb), DFW, 40); g_dslider = meow_slider_create(r_slider.x, r_slider.y, r_slider.w, 0, 100, g_ds.slider); SLOT(g_dslider, r_slider.x, r_slider.y, r_slider.w, r_slider.h); yb += 48;
+    g_slider_cid = meow_draw_custom_register(D_TITLE_Z, r_slider_txt.x, r_slider_txt.y,
+                                             r_slider_txt.w, r_slider_txt.h,
+                                             demo_draw_slider_val, NULL);
 
     r_dtf = RX(DCL_X, SY(yb), DFW, 44); g_dtf = meow_textfield_create(r_dtf.x, r_dtf.y, r_dtf.w, r_dtf.h, "Type here...", g_ds.tf, 32, MEOW_IME_ASCII); SLOT(g_dtf, r_dtf.x, r_dtf.y, r_dtf.w, r_dtf.h); yb += 54;
 
@@ -332,27 +371,14 @@ static void demo_build_at(int scroll)
 #undef SLOT
 }
 
-/* demo 全页重绘：背景 + 内容控件(已定位) + 标题 + slider 值 + chrome(后画覆盖) + 内容区 flush */
+/* demo 全页重绘：整帧按 z 序重画全部（set_page_bg 清底 + 注册表按 z 升序）。
+ * 此前手工遍历 g_dslot/g_dtitle/后画 chrome 已删；现在自动 z 排：内容(0..127)→标题/slider值(128)
+ * →chrome(999 置顶)，与旧绘制序一致，但「清底+重画」由 SDK 统一按 z 保证（P1 修法下沉）。 */
 static void demo_paint(void)
 {
     const meow_theme *th = meow_theme_get();
-    int sb = meow_ui_statusbar_height();
-
-    meow_ui_fill_rect(0, sb, 480, 720 - sb, th->bg);
-
-    for (int i = 0; i < g_dslot_n; i++) meow_widget_draw(g_dslot[i].w);
-    for (int i = 0; i < g_dtitle_n; i++)
-        meow_ui_text(g_dtitle[i].x, g_dtitle[i].y, g_dtitle[i].s, 20, th->primary);
-    if (g_dslider) {
-        char buf[28]; snprintf(buf, sizeof buf, "slider = %d", meow_slider_get(g_dslider));
-        meow_ui_text(r_slider_txt.x, r_slider_txt.y, buf, 20, th->dim);
-    }
-    /* chrome（固定；后画覆盖内容溢出区） */
-    meow_widget_draw(g_tb);
-    meow_widget_draw(g_nav);
-    meow_widget_draw(g_fab);
-
-    meow_ui_flush_region(0, sb, 480, 720 - sb);
+    meow_ui_set_page_bg(th->bg);   /* 页面底 = 主题 bg（区域/整帧重画清底用） */
+    meow_ui_paint_full();          /* 整帧按 z 序重画 */
 }
 
 /* 重建内容到指定 scroll（clamp 到 [0, max_scroll]）；进入/滚动共用 */
@@ -369,51 +395,14 @@ static void demo_rebuild_to(int scroll)
     demo_paint();
 }
 
-/* 两矩形是否相交（P1：局部重绘时判定哪些控件落在该区） */
-static int d_rect_overlap(rect_t a, rect_t b)
-{
-    return a.x < b.x + b.w && a.x + a.w > b.x && a.y < b.y + b.h && a.y + a.h > b.y;
-}
-
-/* 局部刷新一个区域：清底 + 按 demo_paint 同序重画「落在该区的所有控件/文本/chrome」，再 flush。
- * 根治 P1：旧 d_redraw 只清底 + 重画单个控件，会把重叠区里上层控件（chrome 如 FAB/导航栏）
- * 一并清掉、只刷单个控件矩形 → 下层动态控件（如圆形进度条实时重绘）盖住/抹掉上层浮层。
- * 修法：局部刷新=重画该区内完整 z 栈（内容→标题→slider 值→chrome，与整帧 paint 一致），
- * 下层动态重绘不再抹掉上层。仍是局部（只画相交控件，不整帧、不冲状态栏）。 */
-static void d_paint_region(rect_t r)
-{
-    if (r.w <= 0 || r.h <= 0) return;
-    const meow_theme *th = meow_theme_get();
-    meow_ui_fill_rect(r.x, r.y, r.w, r.h, th->bg);
-    for (int i = 0; i < g_dslot_n; i++)
-        if (d_rect_overlap(g_dslot[i].r, r)) meow_widget_draw(g_dslot[i].w);
-    for (int i = 0; i < g_dtitle_n; i++)
-        if (g_dtitle[i].y < r.y + r.h && g_dtitle[i].y + meow_ui_text_height(20) > r.y &&
-            g_dtitle[i].x < r.x + r.w && g_dtitle[i].x + meow_ui_text_width(g_dtitle[i].s, 20) > r.x)
-            meow_ui_text(g_dtitle[i].x, g_dtitle[i].y, g_dtitle[i].s, 20, th->primary);
-    if (g_dslider && d_rect_overlap(r_slider_txt, r)) {
-        char buf[28]; snprintf(buf, sizeof buf, "slider = %d", meow_slider_get(g_dslider));
-        meow_ui_text(r_slider_txt.x, r_slider_txt.y, buf, 20, th->dim);
-    }
-    /* chrome（固定；后画保证覆盖内容区溢出） */
-    if (d_rect_overlap(r_tb, r))  meow_widget_draw(g_tb);
-    if (d_rect_overlap(r_nav, r)) meow_widget_draw(g_nav);
-    if (d_rect_overlap(r_fab, r)) meow_widget_draw(g_fab);
-    meow_ui_flush_region(r.x, r.y, r.w, r.h);
-}
-
-/* 局部刷新一个控件：整区清底 + 重画重叠 z 栈（w 仅用于取矩形；重画逻辑见 d_paint_region） */
-static void d_redraw(meow_widget *w, rect_t r)
-{
-    (void)w;
-    d_paint_region(r);
-}
-
+/* 局部刷新统一走 SDK meow_ui_invalidate（清底 + 按 z 重画相交绘制物 + 上屏）；
+ * 旧 d_paint_region/d_redraw/d_rect_overlap（App 层 z 栈重画）已删除、下沉到 SDK（§6.2）。
+ * 局部刷新一控件：整区清底 + 重画重叠 z 栈由注册表完成。 */
 static void d_toggle_sel(meow_widget *w, rect_t r)
 {
     if (!w) return;
     meow_widget_set_selected(w, !meow_widget_selected(w));
-    d_redraw(w, r);
+    meow_ui_invalidate(r.x, r.y, r.w, r.h);
 }
 
 /* Tap：落点在内容控件上，返回 1=已消费 */
@@ -423,29 +412,29 @@ static int demo_content_tap(int x, int y)
 
     for (int i = 0; i < 5; i++)
         if (meow_widget_hit(g_dbtn_b[i], x, y)) { d_toggle_sel(g_dbtn_b[i], r_btn[i]); g_ds.btn[i] = meow_widget_selected(g_dbtn_b[i]); return 1; }
-    if (meow_widget_hit(g_dr1, x, y)) { meow_widget_set_selected(g_dr1, 1); meow_widget_set_selected(g_dr2, 0); g_ds.r1 = 1; g_ds.r2 = 0; d_redraw(g_dr1, r_dr1); d_redraw(g_dr2, r_dr2); return 1; }
-    if (meow_widget_hit(g_dr2, x, y)) { meow_widget_set_selected(g_dr2, 1); meow_widget_set_selected(g_dr1, 0); g_ds.r2 = 1; g_ds.r1 = 0; d_redraw(g_dr1, r_dr1); d_redraw(g_dr2, r_dr2); return 1; }
+    if (meow_widget_hit(g_dr1, x, y)) { meow_widget_set_selected(g_dr1, 1); meow_widget_set_selected(g_dr2, 0); g_ds.r1 = 1; g_ds.r2 = 0; meow_ui_invalidate(r_dr1.x, r_dr1.y, r_dr1.w, r_dr1.h); meow_ui_invalidate(r_dr2.x, r_dr2.y, r_dr2.w, r_dr2.h); return 1; }
+    if (meow_widget_hit(g_dr2, x, y)) { meow_widget_set_selected(g_dr2, 1); meow_widget_set_selected(g_dr1, 0); g_ds.r2 = 1; g_ds.r1 = 0; meow_ui_invalidate(r_dr1.x, r_dr1.y, r_dr1.w, r_dr1.h); meow_ui_invalidate(r_dr2.x, r_dr2.y, r_dr2.w, r_dr2.h); return 1; }
     if (meow_widget_hit(g_dcb, x, y)) { d_toggle_sel(g_dcb, r_dcb); g_ds.ck = meow_widget_selected(g_dcb); return 1; }
-    if (meow_widget_hit(g_dsw, x, y)) { g_ds.sw_on = !meow_switch_get(g_dsw); meow_switch_set(g_dsw, g_ds.sw_on); d_redraw(g_dsw, r_dsw); return 1; }
+    if (meow_widget_hit(g_dsw, x, y)) { g_ds.sw_on = !meow_switch_get(g_dsw); meow_switch_set(g_dsw, g_ds.sw_on); meow_ui_invalidate(r_dsw.x, r_dsw.y, r_dsw.w, r_dsw.h); return 1; }
     if (meow_widget_hit(g_dslider, x, y)) { demo_slider_drag(x); return 1; }
     if (meow_widget_hit(g_dtf, x, y)) {
         meow_textfield_activate(g_dtf);   /* 阻塞 IME，返回后刷新 + 状态回写 */
         strncpy(g_ds.tf, meow_textfield_text(g_dtf), sizeof g_ds.tf - 1);
         g_ds.tf[sizeof g_ds.tf - 1] = 0;
-        d_redraw(g_dtf, r_dtf);
+        meow_ui_invalidate(r_dtf.x, r_dtf.y, r_dtf.w, r_dtf.h);
         return 1;
     }
     if (meow_widget_hit(g_dcard_btn, x, y)) { d_toggle_sel(g_dcard_btn, r_cardbtn); g_ds.card = meow_widget_selected(g_dcard_btn); return 1; }
     if (g_dtab) {
         int t = meow_tabbar_hit(g_dtab, x, y);
-        if (t >= 0) { g_ds.tab = t; meow_tabbar_set_selected(g_dtab, t); d_redraw(g_dtab, r_tab); return 1; }
+        if (t >= 0) { g_ds.tab = t; meow_tabbar_set_selected(g_dtab, t); meow_ui_invalidate(r_tab.x, r_tab.y, r_tab.w, r_tab.h); return 1; }
     }
-    if (meow_widget_hit(g_dbtn_dlg, x, y)) { meow_dialog_show(g_dlg); meow_log(MEOW_LOG_INFO, "dialog result=%d", meow_dialog_result(g_dlg)); d_redraw(g_dbtn_dlg, r_dlg); return 1; }
-    if (meow_widget_hit(g_dbtn_sheet, x, y)) { int r = meow_sheet_open(g_sheet); meow_log(MEOW_LOG_INFO, "sheet result=%d", r); d_redraw(g_dbtn_sheet, r_sheet); return 1; }
+    if (meow_widget_hit(g_dbtn_dlg, x, y)) { meow_dialog_show(g_dlg); meow_log(MEOW_LOG_INFO, "dialog result=%d", meow_dialog_result(g_dlg)); meow_ui_invalidate(r_dlg.x, r_dlg.y, r_dlg.w, r_dlg.h); return 1; }
+    if (meow_widget_hit(g_dbtn_sheet, x, y)) { int r = meow_sheet_open(g_sheet); meow_log(MEOW_LOG_INFO, "sheet result=%d", r); meow_ui_invalidate(r_sheet.x, r_sheet.y, r_sheet.w, r_sheet.h); return 1; }
     if (meow_widget_hit(g_dlc, x, y)) {
         g_demo_focus = 1;
         int li = meow_list_tap_at(g_dlc, x, y);   /* M2.71-bug8：命中行→置选中并高亮 */
-        if (li >= 0) { g_ds.list_sel = li; d_redraw(g_dlc, r_list); }
+        if (li >= 0) { g_ds.list_sel = li; meow_ui_invalidate(r_list.x, r_list.y, r_list.w, r_list.h); }
         return 1;
     }
     return 0;
@@ -463,12 +452,13 @@ static void demo_on_tap(int x, int y)
         char lb[16]; snprintf(lb, sizeof lb, "+%d", g_demo_fab);
         meow_widget_free(g_fab);
         g_fab = meow_fab_create(r_fab.x, r_fab.y, 56, lb);
-        d_paint_region(r_fab);   /* 重画 FAB 及其下重叠内容（z 序一致，防抹掉下层） */
+        meow_widget_set_z(g_fab, 999);   /* 重建后重挂顶：新 entry 自动 z 低，须显式置顶 */
+        meow_ui_invalidate(r_fab.x, r_fab.y, r_fab.w, r_fab.h);   /* 重画 FAB 及其下重叠 z 栈 */
         return;
     }
     if (g_nav) {
         int idx = meow_navigationbar_hit(g_nav, x, y);
-        if (idx >= 0) { meow_navigationbar_set_selected(g_nav, idx); d_redraw(g_nav, r_nav); return; }
+        if (idx >= 0) { meow_navigationbar_set_selected(g_nav, idx); meow_ui_invalidate(r_nav.x, r_nav.y, r_nav.w, r_nav.h); return; }
     }
     if (demo_content_tap(x, y)) return;
 }
@@ -481,8 +471,8 @@ static void demo_tick(uint64_t now)
     g_demo_prog_last = now;
     g_ds.prog = (g_ds.prog + 3) % 101;
     g_demo_prog = g_ds.prog;
-    meow_progress_set(g_dprl, g_demo_prog); d_redraw(g_dprl, r_prl);
-    meow_progress_set(g_dprc, g_demo_prog); d_redraw(g_dprc, r_prc);
+    meow_progress_set(g_dprl, g_demo_prog); meow_ui_invalidate(r_prl.x, r_prl.y, r_prl.w, r_prl.h);
+    meow_progress_set(g_dprc, g_demo_prog); meow_ui_invalidate(r_prc.x, r_prc.y, r_prc.w, r_prc.h);
 }
 
 /* 按触碰 X 落 slider 值并局部刷（按下即定位 + 拖动实时，M2.71-bug2） */
@@ -491,8 +481,8 @@ static void demo_slider_drag(int x)
     int frac = x - r_slider.x; if (frac < 0) frac = 0; if (frac > r_slider.w) frac = r_slider.w;
     g_ds.slider = frac * 100 / r_slider.w;
     meow_slider_set(g_dslider, g_ds.slider);
-    d_redraw(g_dslider, r_slider);
-    d_paint_region(r_slider_txt);   /* 重画 slider 值文本（z 序一致） */
+    meow_ui_invalidate(r_slider.x, r_slider.y, r_slider.w, r_slider.h);
+    meow_ui_invalidate(r_slider_txt.x, r_slider_txt.y, r_slider_txt.w, r_slider_txt.h);  /* 重画值文本 */
 }
 
 /* demo 页 on_touch_down：锁一种拖拽（slider > list > 页内容）。非 demo 态跳过。
@@ -522,7 +512,7 @@ static void demo_touch_move(int x, int y)
     if (g_drag_slider) { demo_slider_drag(x); return; }
     if (g_drag_list) {
         int dy = y - g_drag_list_last_y; g_drag_list_last_y = y;
-        if (dy) { meow_list_scroll_by(g_dlc, -dy); g_ds.list = meow_list_scroll(g_dlc); d_redraw(g_dlc, r_list); }
+        if (dy) { meow_list_scroll_by(g_dlc, -dy); g_ds.list = meow_list_scroll(g_dlc); meow_ui_invalidate(r_list.x, r_list.y, r_list.w, r_list.h); }
         return;
     }
     if (g_drag_page) {
@@ -546,7 +536,7 @@ static void demo_swipe(int dir, int dist)
     if (g_demo_focus && g_dlc) {
         meow_list_scroll_by(g_dlc, del);
         g_ds.list = meow_list_scroll(g_dlc);
-        d_redraw(g_dlc, r_list);   /* 列表区局部刷新 */
+        meow_ui_invalidate(r_list.x, r_list.y, r_list.w, r_list.h);   /* 列表区局部刷新 */
     } else {
         demo_rebuild_to(g_demo_scroll + del);
     }
@@ -575,6 +565,10 @@ static void demo_init(void)
     meow_navigationbar_add_item(g_nav, "More");
     meow_navigationbar_set_selected(g_nav, 0);
     r_fab = RX(406, 616, 56, 56); g_fab = meow_fab_create(406, 616, 56, "+");
+    /* chrome 显式置顶（§6.2 置顶）：> 一切自动 z(127)，区域重画/整帧都最后画 chrome。 */
+    meow_widget_set_z(g_tb, 999);
+    meow_widget_set_z(g_nav, 999);
+    meow_widget_set_z(g_fab, 999);
     demo_build_at(0);
     meow_ui_activity_pop();
     g_demo_scroll = 0;