fix: Improve color theme button colors for better distinction

**Issue**: Color theme button colors were too similar to other buttons
- Light mode (sun): Orange #f39c12 - same as keyboard button
- Dark mode (moon): Blue #3498db - same as zoom button

**Fix**: Updated to more distinctive colors

Light mode (sun):
- Was: Orange #f39c12 (same as keyboard)
- Now: Gold/Bright Yellow #ffd700 (distinct sun color)

Dark mode (moon):
- Was: Bright Blue #3498db (same as zoom)
- Now: Dark Slate Blue #2c3e50 (darker "nighty" blue)

Auto mode:
- Kept: Purple #9b59b6 (already distinctive)

**Result**: Color theme button now has unique, semantic colors that
clearly represent sun (bright yellow) and moon (dark night blue) without
conflicting with other buttons.

Updated both hover and at-bottom states for consistency.

static/css/color-theme.css

@@ -182,11 +182,11 @@
 
 /* Dynamic colors ONLY on hover based on active theme mode */
 .color-theme-switcher:hover[data-theme-mode="light"] {
-  background: #f39c12 !important; /* Warm sun yellow for light mode */
+  background: #ffd700 !important; /* Bright sun yellow (gold) for light mode */
 }
 
 .color-theme-switcher:hover[data-theme-mode="dark"] {
-  background: #3498db !important; /* Cool moon blue for dark mode */
+  background: #2c3e50 !important; /* Dark nighty blue for dark mode */
 }
 
 .color-theme-switcher:hover[data-theme-mode="auto"] {
@@ -202,12 +202,12 @@
 /* At-bottom state - dynamic colors based on theme mode (matches hover) */
 .color-theme-switcher.at-bottom[data-theme-mode="light"] {
   opacity: 1;
-  background: #f39c12 !important; /* Warm sun yellow for light mode */
+  background: #ffd700 !important; /* Bright sun yellow (gold) for light mode */
 }
 
 .color-theme-switcher.at-bottom[data-theme-mode="dark"] {
   opacity: 1;
-  background: #3498db !important; /* Cool moon blue for dark mode */
+  background: #2c3e50 !important; /* Dark nighty blue for dark mode */
 }
 
 .color-theme-switcher.at-bottom[data-theme-mode="auto"] {