Initial commit: Developer Tools MVP with visual editor

- Complete React app with 7 developer tools
- JSON Tool with visual structured editor
- Serialize Tool with visual structured editor
- URL, Base64, CSV/JSON, Beautifier, Diff tools
- Responsive navigation with dropdown menu
- Dark/light mode toggle
- Mobile-responsive design with sticky header
- All tools working with copy/paste functionality

node_modules/autoprefixer/lib/hacks/animation.js

@@ -0,0 +1,17 @@
+let Declaration = require('../declaration')
+
+class Animation extends Declaration {
+  /**
+   * Don’t add prefixes for modern values.
+   */
+  check(decl) {
+    return !decl.value.split(/\s+/).some(i => {
+      let lower = i.toLowerCase()
+      return lower === 'reverse' || lower === 'alternate-reverse'
+    })
+  }
+}
+
+Animation.names = ['animation', 'animation-direction']
+
+module.exports = Animation