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/css-blank-pseudo/dist/index.cjs

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+"use strict";function e(e){return e&&"object"==typeof e&&"default"in e?e:{default:e}}var t=e(require("postcss-selector-parser"));const r=e=>{const r=String(Object(e).replaceWith||"[blank]"),s=t.default().astSync(r),o=Boolean(!("preserve"in Object(e))||e.preserve);return{postcssPlugin:"css-blank-pseudo",Rule:(e,{result:r})=>{if(-1===e.selector.indexOf(":blank"))return;let n;try{const r=t.default((e=>{e.walkPseudos((e=>{":blank"===e.value&&(e.nodes&&e.nodes.length||e.replaceWith(s.clone()))}))})).processSync(e.selector);n=String(r)}catch(t){return void e.warn(r,`Failed to parse selector : ${e.selector}`)}if(void 0===n)return;if(n===e.selector)return;const c=e.clone({selector:n});o?e.before(c):e.replaceWith(c)}}};r.postcss=!0,module.exports=r;