polish: Midnight theme redesign — proper elevation + refined palette

- Base shifts from pure #0a0a0a to a barely-cool #0d0e12 ("midnight sky"
  reads as deep blue-black, not generic OLED black).
- Even elevation ladder: bg -> bg-raised -> bg-hover now reads as clear,
  perceptible steps instead of muddy near-duplicates.
- Three-tier text hierarchy with verified contrast: primary near-white,
  muted (WCAG AA on bg), dim for timestamps/hints.
- More luminous violet accent (#a78bfa) with proper pressed variant.
- Semantic colours retuned to harmonise (zap warm gold, success fresh
  green, danger softer red).

Mirrored into index.css @theme so pre-applyTheme initial paint matches.

src/index.css

@@ -4,22 +4,22 @@
   /* Colour vars below mirror the `midnight` theme in src/lib/themes.ts.
      applyTheme() overrides these at runtime — keep them in sync so the
      pre-theme initial paint matches and there is no colour flash. */
-  --color-bg: #0a0a0a;
-  --color-bg-raised: #121212;
-  --color-bg-hover: #1c1c1c;
-  --color-border: #2a2a2a;
-  --color-border-subtle: #1e1e1e;
-  --color-text: #e8e8e8;
-  --color-text-muted: #a0a0a0;
-  --color-text-dim: #6e6e6e;
-  --color-accent: #9d7aff;
+  --color-bg: #0d0e12;
+  --color-bg-raised: #161820;
+  --color-bg-hover: #1f222c;
+  --color-border: #2b2e3a;
+  --color-border-subtle: #1d1f29;
+  --color-text: #e8e9ee;
+  --color-text-muted: #9a9db0;
+  --color-text-dim: #686b7d;
+  --color-accent: #a78bfa;
   --color-accent-hover: #8b5cf6;
   --color-accent-text: #ffffff;
-  --color-zap: #f59e0b;
-  --color-zap-text: #000000;
-  --color-danger: #ef4444;
-  --color-warning: #f59e0b;
-  --color-success: #22c55e;
+  --color-zap: #f5b73d;
+  --color-zap-text: #15161a;
+  --color-danger: #ef5f6b;
+  --color-warning: #f5b73d;
+  --color-success: #4cc98a;
   --font-ui: system-ui, -apple-system, "Segoe UI", Roboto, "Helvetica Neue", sans-serif;
   --font-mono: "JetBrains Mono", "Fira Code", "SF Mono", monospace;
   --font-reading: Georgia, "Times New Roman", "Noto Serif", serif;

src/lib/themes.ts

@@ -28,22 +28,22 @@ export const themes: Theme[] = [
     id: "midnight",
     name: "Midnight",
     colors: {
-      bg: "#0a0a0a",
-      "bg-raised": "#121212",
-      "bg-hover": "#1c1c1c",
-      border: "#2a2a2a",
-      "border-subtle": "#1e1e1e",
-      text: "#e8e8e8",
-      "text-muted": "#a0a0a0",
-      "text-dim": "#6e6e6e",
-      accent: "#9d7aff",
+      bg: "#0d0e12",
+      "bg-raised": "#161820",
+      "bg-hover": "#1f222c",
+      border: "#2b2e3a",
+      "border-subtle": "#1d1f29",
+      text: "#e8e9ee",
+      "text-muted": "#9a9db0",
+      "text-dim": "#686b7d",
+      accent: "#a78bfa",
       "accent-hover": "#8b5cf6",
       "accent-text": "#ffffff",
-      zap: "#f59e0b",
-      "zap-text": "#000000",
-      danger: "#ef4444",
-      warning: "#f59e0b",
-      success: "#22c55e",
+      zap: "#f5b73d",
+      "zap-text": "#15161a",
+      danger: "#ef5f6b",
+      warning: "#f5b73d",
+      success: "#4cc98a",
     },
   },
   {