Added base styles, variables, and mixins

package.json

@@ -13,15 +13,14 @@
     "@keystatic/core": "^0.5.48",
     "@keystatic/next": "^5.0.4",
     "@markdoc/markdoc": "^0.5.4",
-    "@tailwindcss/postcss": "^4.1.13",
     "next": "15.5.3",
-    "postcss": "^8.5.6",
     "react": "19.1.0",
-    "react-dom": "19.1.0",
-    "tailwindcss": "^4.1.13"
+    "react-dom": "19.1.0"
   },
   "devDependencies": {
+    "@csstools/postcss-global-data": "^3.1.0",
     "@eslint/eslintrc": "^3",
+    "@fullhuman/postcss-purgecss": "^7.0.2",
     "@types/node": "^20",
     "@types/react": "^19",
     "@types/react-dom": "^19",
@@ -31,12 +30,20 @@
     "eslint-config-next": "15.5.3",
     "eslint-config-prettier": "^10.1.8",
     "eslint-plugin-mdx": "^3.6.2",
+    "glob-all": "^3.3.1",
+    "postcss": "^8.5.6",
+    "postcss-easings": "^4.0.0",
+    "postcss-functions": "^4.0.2",
+    "postcss-import": "^16.1.1",
+    "postcss-mixins": "^12.1.2",
+    "postcss-nesting": "^13.0.2",
+    "postcss-preset-env": "^10.3.1",
+    "postcss-utilities": "^0.8.4",
     "prettier": "^3.6.2",
     "stylelint": "^16.24.0",
     "stylelint-config-clean-order": "^7.0.0",
     "stylelint-config-html": "^1.1.0",
     "stylelint-config-standard": "^39.0.0",
-    "stylelint-config-tailwindcss": "^1.0.0",
     "typescript": "^5"
   }
 }