Revert "Refine settings and panel preferences"

This reverts commit 760ab62c10.

src/app.css

@@ -22,23 +22,6 @@
   --shadow: 0 1px 2px rgba(17, 24, 39, 0.04);
 }
 
-:root[data-theme='dark'] {
-  color-scheme: dark;
-  --page-bg: #111827;
-  --surface: #18212f;
-  --surface-muted: #1f2937;
-  --border: #334155;
-  --border-strong: #475569;
-  --text: #f8fafc;
-  --muted: #94a3b8;
-  --accent: #60a5fa;
-  --accent-muted: rgba(96, 165, 250, 0.15);
-  --success: #4ade80;
-  --warning: #fbbf24;
-  --danger: #f87171;
-  --shadow: 0 1px 2px rgba(2, 6, 23, 0.35);
-}
-
 * {
   box-sizing: border-box;
 }
@@ -389,13 +372,13 @@ button,
 .usage-bar {
   height: 8px;
   border-radius: 999px;
-  background: color-mix(in srgb, var(--border) 70%, transparent);
+  background: #eceff3;
   overflow: hidden;
 }
 
 .usage-bar div {
   height: 100%;
-  background: color-mix(in srgb, var(--accent) 55%, var(--muted));
+  background: #94a3b8;
 }
 
 .event-row,
@@ -625,8 +608,8 @@ pre {
   overflow: auto;
   border: 1px solid var(--border);
   border-radius: 10px;
-  background: color-mix(in srgb, var(--surface-muted) 80%, var(--surface));
-  color: var(--text);
+  background: #fbfbfc;
+  color: #1f2937;
   font: 13px/1.55 Consolas, "Courier New", monospace;
 }