diff --git a/plugins/sentinel/dashboard.html b/plugins/sentinel/dashboard.html
index 84b1fe5..8cfdf6b 100644
--- a/plugins/sentinel/dashboard.html
+++ b/plugins/sentinel/dashboard.html
@@ -63,7 +63,7 @@
     #sentinel-grid.layout-row .mtr-data { flex:1;min-width:0;white-space:nowrap }
     #sentinel-grid.layout-row .mtr-data .rlabel { font-size:.7rem;color:var(--text-dim);text-transform:uppercase;margin-right:6px }
     #sentinel-grid.layout-row .mtr-data .rval { font-weight:600 }
-    #sentinel-grid.layout-row .mtr canvas { border-radius:3px;background:var(--md-sys-color-surface-container-lowest);flex-shrink:1;max-width:180px;min-width:100px }
+    #sentinel-grid.layout-row .mtr canvas { border-radius:3px;background:rgba(128,128,128,0.08);flex-shrink:1;max-width:180px;min-width:100px }
     #sentinel-grid.layout-row .node-time { margin-top:4px }
     #sentinel-grid.layout-row .metric-bar { display:none }
     .metric-row { display:flex; gap:12px; margin-bottom:8px }