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/postcss-normalize/index.d.ts

@@ -0,0 +1,26 @@
+import type * as PostCSS from 'postcss'
+
+export type PluginOptions = {
+	/** Determines whether multiple, duplicate insertions are allowed */
+	allowDuplicates?: boolean
+	/** Defines an override of the project’s browserslist for this plugin. */
+	browsers?: string
+	/** Defines whether imports from this plugin will always be inserted at the beginning of a CSS file. */
+	forceImport?: boolean
+}
+
+export type Plugin = {
+	(pluginOptions?: PluginOptions): {
+		postcssPlugin: 'postcss-normalize'
+		Once(root: PostCSS.Root): void
+		postcssImport: {
+			load(filename: string, importOptions: any): {}
+			resolve(id: string, basedir: string, importOptions: any): {}
+		}
+	}
+	postcss: true
+}
+
+declare const plugin: Plugin
+
+export default plugin