refactor(ui): improve UI/UX design and spacing

- Increase card padding and gaps for better visual hierarchy
- Add hover lift effect to cards with smooth transitions
- Improve typography with larger headings and better line-height
- Darken meta text colors for better readability
- Add checkbox styling with accent color
- Make tags interactive with hover effects
- Add mobile responsive styles for forms and footer
- Replace Unicode arrows with SVG icons
- Improve focus styles for accessibility
- Increase badge padding and font-weight
- Add subtle shadow to cards by default

static/css/base.css

@@ -102,7 +102,15 @@ pre code {
 /* Focus styles */
 :focus-visible {
   outline: 2px solid var(--color-primary);
-  outline-offset: 2px;
+  outline-offset: 3px;
+}
+
+/* Enhanced link focus for accessibility */
+a:focus-visible,
+.btn:focus-visible,
+.nav-link:focus-visible {
+  outline: 2px solid var(--color-primary);
+  outline-offset: 4px;
 }
 
 /* Scrollbar */