feat: Implement website structure

- Add navigation with Themes, Puzzles, and Miscellany.
- Create "coming soon" pages for Puzzles and Miscellany.
- Create a Themes page with cards for various topics.
- Implement basic boxy layout.
- Prepare for future interactive additions and filtering.
- Set up for Netlify deployment.

tailwind.config.ts

@@ -52,6 +52,10 @@ export default {
 					DEFAULT: 'hsl(var(--card))',
 					foreground: 'hsl(var(--card-foreground))'
 				},
+				surface: 'hsl(var(--surface))',
+				'surface-variant': 'hsl(var(--surface-variant))',
+				outline: 'hsl(var(--outline))',
+				'outline-variant': 'hsl(var(--outline-variant))',
 				sidebar: {
 					DEFAULT: 'hsl(var(--sidebar-background))',
 					foreground: 'hsl(var(--sidebar-foreground))',
@@ -68,6 +72,14 @@ export default {
 				md: 'calc(var(--radius) - 2px)',
 				sm: 'calc(var(--radius) - 4px)'
 			},
+			boxShadow: {
+				'card': 'var(--shadow-card)',
+				'card-hover': 'var(--shadow-card-hover)',
+			},
+			backgroundImage: {
+				'gradient-primary': 'var(--gradient-primary)',
+				'gradient-secondary': 'var(--gradient-secondary)',
+			},
 			keyframes: {
 				'accordion-down': {
 					from: {