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/grid-area.js

@@ -0,0 +1,34 @@
+let Declaration = require('../declaration')
+let utils = require('./grid-utils')
+
+class GridArea extends Declaration {
+  /**
+   * Translate grid-area to separate -ms- prefixed properties
+   */
+  insert(decl, prefix, prefixes, result) {
+    if (prefix !== '-ms-') return super.insert(decl, prefix, prefixes)
+
+    let values = utils.parse(decl)
+
+    let [rowStart, rowSpan] = utils.translate(values, 0, 2)
+    let [columnStart, columnSpan] = utils.translate(values, 1, 3)
+
+    ;[
+      ['grid-row', rowStart],
+      ['grid-row-span', rowSpan],
+      ['grid-column', columnStart],
+      ['grid-column-span', columnSpan]
+    ].forEach(([prop, value]) => {
+      utils.insertDecl(decl, prop, value)
+    })
+
+    utils.warnTemplateSelectorNotFound(decl, result)
+    utils.warnIfGridRowColumnExists(decl, result)
+
+    return undefined
+  }
+}
+
+GridArea.names = ['grid-area']
+
+module.exports = GridArea