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

tailwind.config.js

@@ -0,0 +1,29 @@
+/** @type {import('tailwindcss').Config} */
+module.exports = {
+  content: [
+    "./src/**/*.{js,jsx,ts,tsx}",
+  ],
+  darkMode: 'class', // Enable manual dark mode control via class
+  theme: {
+    extend: {
+      colors: {
+        primary: {
+          50: '#f0f9ff',
+          100: '#e0f2fe',
+          200: '#bae6fd',
+          300: '#7dd3fc',
+          400: '#38bdf8',
+          500: '#0ea5e9',
+          600: '#0284c7',
+          700: '#0369a1',
+          800: '#075985',
+          900: '#0c4a6e',
+        }
+      },
+      fontFamily: {
+        mono: ['JetBrains Mono', 'Monaco', 'Cascadia Code', 'Segoe UI Mono', 'Roboto Mono', 'Oxygen Mono', 'Ubuntu Monospace', 'Source Code Pro', 'Fira Code', 'Droid Sans Mono', 'Courier New', 'monospace'],
+      }
+    },
+  },
+  plugins: [],
+}