chore: migrate tailwindcss from v3 to v4

package.json

@@ -31,7 +31,8 @@
     "eslint": "9.39.3",
     "eslint-config-next": "16.1.6",
     "postcss": "8.5.6",
-    "tailwindcss": "3.4.19",
+    "@tailwindcss/postcss": "4.2.0",
+    "tailwindcss": "4.2.0",
     "typescript": "5.9.3"
   }
 }

postcss.config.mjs

@@ -1,7 +1,7 @@
 /** @type {import('postcss-load-config').Config} */
 const config = {
   plugins: {
-    tailwindcss: {},
+    "@tailwindcss/postcss": {},
   },
 };
 

src/app/globals.css

@@ -1,64 +1,57 @@
-@tailwind base;
-@tailwind components;
-@tailwind utilities;
+@import "tailwindcss";
 
-h1 {
+@theme {
+  --color-background: var(--background);
+  --color-foreground: var(--foreground);
+}
+
+@layer base {
+  h1 {
     @apply text-4xl;
-}
+  }
 
-h2 {
+  h2 {
     @apply text-2xl;
-}
+  }
 
-a {
+  a {
     @apply underline;
-}
+  }
 
-li {
+  li {
     @apply list-disc;
     @apply list-inside;
     @apply text-left;
-}
+  }
 
-p {
+  p {
     @apply text-justify;
     @apply mb-2;
-}
+  }
 
-img {
+  img {
     @apply mx-auto;
-}
+  }
 
-blockquote,
-blockquote p {
+  blockquote,
+  blockquote p {
     @apply text-center;
-}
+  }
 
-.is-dark blockquote,
-.is-dark blockquote p {
-  color: var(--foreground);
-}
-
-blockquote {
+  blockquote {
     border-left: 5px solid var(--accent);
     box-shadow: inset 4px 0 10px -4px var(--accent);
     padding-left: 1rem;
     margin: 1rem;
-}
-
-@layer utilities {
-  .text-balance {
-    text-wrap: balance;
   }
-}
 
-figcaption {
+  figcaption {
     @apply text-sm;
     @apply text-center;
     @apply italic;
-}
+  }
 
-pre {
+  pre {
     @apply text-left;
     @apply bg-gray-100;
     @apply p-2;
@@ -70,9 +63,9 @@ pre {
     @apply break-words;
     @apply text-sm;
     @apply font-mono;
-}
+  }
 
-code:not(pre code) {
+  code:not(pre code) {
     @apply text-sm;
     @apply font-mono;
     @apply bg-gray-100;
@@ -83,4 +76,16 @@ code:not(pre code) {
     @apply overflow-x-auto;
     @apply whitespace-pre-wrap;
     @apply break-words;
+  }
+}
+
+.is-dark blockquote,
+.is-dark blockquote p {
+  color: var(--foreground);
+}
+
+@layer utilities {
+  .text-balance {
+    text-wrap: balance;
+  }
 }

tailwind.config.ts

@@ -1,18 +0,0 @@
-import type { Config } from "tailwindcss";
-
-export default {
-  content: [
-    "./src/pages/**/*.{js,ts,jsx,tsx,mdx}",
-    "./src/components/**/*.{js,ts,jsx,tsx,mdx}",
-    "./src/app/**/*.{js,ts,jsx,tsx,mdx}",
-  ],
-  theme: {
-    extend: {
-      colors: {
-        background: "var(--background)",
-        foreground: "var(--foreground)",
-      },
-    },
-  },
-  plugins: [],
-} satisfies Config;