feat: update dependencies and add new styles

- Added node and sass to dependencies in package.json
- Added @types/node to devDependencies
- Removed unused CSS files and replaced them with SCSS files
- Updated import paths in App.tsx and Blog.tsx to use new aliasing
- Configured TypeScript paths for easier imports
- Updated Vite config to include path aliases
- Created new SCSS files for About, Blog, Error, and Main styles
- Added a variables file for color and effect variables
- Updated index.scss for global styles and responsive adjustments

package.json

@@ -11,14 +11,17 @@
   },
   "dependencies": {
     "@testing-library/react": "^16.3.0",
+    "node": "^20.19.2",
     "react": "^19.1.0",
     "react-dom": "^19.1.0",
     "react-router-dom": "^7.6.0",
+    "sass": "^1.89.0",
     "vitest": "^3.1.3"
   },
   "devDependencies": {
     "@eslint/js": "^9.25.0",
     "@testing-library/jest-dom": "^6.6.3",
+    "@types/node": "^22.15.18",
     "@types/react": "^19.1.2",
     "@types/react-dom": "^19.1.2",
     "@vitejs/plugin-react": "^4.4.1",
@@ -26,6 +29,7 @@
     "eslint-plugin-react-hooks": "^5.2.0",
     "eslint-plugin-react-refresh": "^0.4.19",
     "globals": "^16.0.0",
+    "path": "^0.12.7",
     "typescript": "~5.8.3",
     "typescript-eslint": "^8.30.1",
     "vite": "^6.3.5"