chore(deps): update tailwindcss to v4

Author: bmulholland

assets/css/main.css

@@ -1,3 +1,21 @@
-@tailwind base;
-@tailwind components;
-@tailwind utilities;
+@import "tailwindcss";
+
+@config '../../tailwind.config.ts';
+
+/*
+  The default border color has changed to `currentColor` in Tailwind CSS v4,
+  so we've added these compatibility styles to make sure everything still
+  looks the same as it did with Tailwind CSS v3.
+
+  If we ever want to remove these styles, we need to add an explicit border
+  color utility to any element that depends on these defaults.
+*/
+@layer base {
+  *,
+  ::after,
+  ::before,
+  ::backdrop,
+  ::file-selector-button {
+    border-color: var(--color-gray-200, currentColor);
+  }
+}

package.json

@@ -142,6 +142,7 @@
     "@primer/octicons-react": "19.14.0",
     "@primer/primitives": "10.3.4",
     "@primer/react": "36.27.0",
+    "@tailwindcss/postcss": "^4.0.0",
     "@testing-library/react": "16.2.0",
     "@types/jest": "29.5.14",
     "@types/node": "22.10.9",
@@ -150,7 +151,6 @@
     "@types/react-dom": "19.0.3",
     "@types/react-router-dom": "5.3.3",
     "@types/semver": "7.5.8",
-    "autoprefixer": "10.4.20",
     "axios": "1.7.9",
     "clsx": "2.1.1",
     "concurrently": "9.1.2",
@@ -176,7 +176,7 @@
     "semver": "7.6.3",
     "styled-components": "6.1.14",
     "tailwind-merge": "2.6.0",
-    "tailwindcss": "3.4.17",
+    "tailwindcss": "4.0.0",
     "terser-webpack-plugin": "5.3.11",
     "ts-jest": "29.2.5",
     "ts-loader": "9.5.2",