feat: add class-variance-authority for card styling and enhance color palettes

- Introduced `class-variance-authority` to manage card component styles, allowing for flexible variant and layout options.
- Added a new color palette for "Fire" to the CSS for improved theming.
- Updated `Card` and `PostCard` components to utilize the new styling system, enhancing visual consistency and responsiveness.
- Refined layout and styling in various components for better user experience.

package.json

@@ -29,6 +29,7 @@
     "@fontsource/inter": "^5.2.8",
     "@iconify/svelte": "^5.2.1",
     "blurhash": "^2.0.5",
+    "class-variance-authority": "^0.7.1",
     "marked": "^17.0.2",
     "sharp": "^0.34.5"
   },