diff --git a/frontend/style.css b/frontend/style.css
index 1af5bd9..23833ba 100644
--- a/frontend/style.css
+++ b/frontend/style.css
@@ -7767,6 +7767,8 @@ body.popup-mode .content-area {
 }
 
 /* ── Dark mode overrides for beta diagrams that ignore themeVariables ── */
+
+/* packet-beta */
 [data-theme="dark"] .mermaid-rendered svg .row rect,
 [data-theme="dark"] .mermaid-rendered svg g[id*="packet"] rect {
   fill: #1e3a5f !important;
@@ -7786,6 +7788,26 @@ body.popup-mode .content-area {
   fill: #c8daf0 !important;
 }
 
+/* xychart-beta — bar fills and line color */
+[data-theme="dark"] .mermaid-rendered svg rect[class*="plot"],
+[data-theme="dark"] .mermaid-rendered svg rect[id*="bar"] {
+  fill: #1e3a5f !important;
+  stroke: #4a7ab5 !important;
+}
+[data-theme="dark"] .mermaid-rendered svg path[class*="plot"],
+[data-theme="dark"] .mermaid-rendered svg path[id*="line"] {
+  stroke: #6a9ad0 !important;
+}
+[data-theme="dark"] .mermaid-fullscreen-content svg rect[class*="plot"],
+[data-theme="dark"] .mermaid-fullscreen-content svg rect[id*="bar"] {
+  fill: #1e3a5f !important;
+  stroke: #4a7ab5 !important;
+}
+[data-theme="dark"] .mermaid-fullscreen-content svg path[class*="plot"],
+[data-theme="dark"] .mermaid-fullscreen-content svg path[id*="line"] {
+  stroke: #6a9ad0 !important;
+}
+
 .mermaid-focus-panel {
   position: fixed; top: 0; right: 0; bottom: 0; width: 480px;
   z-index: 9998; background: var(--bg-secondary);