chore: temporarily disable Tailwind CSS section

- Comment out Tailwind nav links in header and sidebar
- Comment out Tailwind card on landing page
- Remove tailwind from router SECTIONS array
- Remove tailwind from landing page progress tracking

Tailwind content and styles remain in codebase for easy re-enabling.

src/app.js

@@ -2347,7 +2347,7 @@ function renderFooterLessonLinks() {
  * Update progress indicators on landing page
  */
 function updateLandingProgress() {
-	["css", "html", "tailwind", "markdown"].forEach((sectionId) => {
+	["css", "html", "markdown"].forEach((sectionId) => { // tailwind temporarily disabled
 		const progressEl = document.getElementById(`${sectionId}-progress`);
 		if (progressEl) {
 			const sectionModules = getModulesBySection(lessonEngine.modules, sectionId);

src/helpers/router.js

@@ -27,7 +27,7 @@ export const RouteType = {
 /**
  * Valid section IDs
  */
-const SECTIONS = ["css", "html", "tailwind", "markdown"];
+const SECTIONS = ["css", "html", "markdown"]; // tailwind temporarily disabled
 
 /**
  * Valid language codes for URL-based switching

src/index.html

@@ -74,7 +74,7 @@
 					<nav class="main-nav" id="main-nav" aria-label="Main sections">
 						<a href="#css" class="nav-link" data-section="css">CSS</a>
 						<a href="#html" class="nav-link" data-section="html">HTML</a>
-						<a href="#tailwind" class="nav-link" data-section="tailwind">Tailwind</a>
+						<!-- <a href="#tailwind" class="nav-link" data-section="tailwind">Tailwind</a> -->
 						<a href="#markdown" class="nav-link" data-section="markdown">Markdown</a>
 						<a href="#reference/css" class="nav-link nav-link-ref" data-section="reference">Reference</a>
 					</nav>
@@ -163,12 +163,14 @@
 								<p data-i18n="landingHtmlDesc">Semantic markup and native elements</p>
 								<span class="section-card-progress" id="html-progress"></span>
 							</a>
+							<!-- Tailwind temporarily disabled
 							<a href="#tailwind" class="section-card" data-section="tailwind">
 								<div class="section-card-icon" style="background: #26a69a">TW</div>
 								<h3>Tailwind CSS</h3>
 								<p data-i18n="landingTailwindDesc">Utility-first CSS framework</p>
 								<span class="section-card-progress" id="tailwind-progress"></span>
 							</a>
+							-->
 							<a href="#markdown" class="section-card" data-section="markdown">
 								<div class="section-card-icon" style="background: #5b8dd9">MD</div>
 								<h3>Markdown</h3>
@@ -474,7 +476,7 @@
 				<nav class="sidebar-section sidebar-nav-mobile" aria-label="Learning paths">
 					<a href="#css" class="sidebar-nav-link" data-section="css">CSS</a>
 					<a href="#html" class="sidebar-nav-link" data-section="html">HTML</a>
-					<a href="#tailwind" class="sidebar-nav-link" data-section="tailwind">Tailwind</a>
+					<!-- <a href="#tailwind" class="sidebar-nav-link" data-section="tailwind">Tailwind</a> -->
 					<button id="auth-trigger-mobile" class="sidebar-nav-link sidebar-auth-link" data-i18n="authLogin">Log In</button>
 				</nav>