feat: add section color coding to lesson title h2

The lesson title now uses section-specific colors:
- CSS: purple (#9163b8)
- HTML: pink (#d45aa0)
- Tailwind: teal (#1aafb8)

🤖 Generated with [Claude Code](https://claude.com/claude-code)

src/main.css

@@ -1651,6 +1651,13 @@ input:checked + .toggle-slider::before {
 
 .auth-links .btn-text {
 	font-size: 0.875rem;
+	color: var(--primary-color);
+	text-decoration: none;
+}
+
+.auth-links .btn-text:hover {
+	color: var(--primary-color-dark, var(--primary-color));
+	text-decoration: underline;
 }
 
 /* Social Login */
@@ -3633,6 +3640,19 @@ body[data-section="tailwind"] .section-progress-bar .progress-fill {
 	color: #1aafb8;
 }
 
+/* Lesson title h2 section colors */
+body[data-section="css"] #lesson-title {
+	color: #9163b8;
+}
+
+body[data-section="html"] #lesson-title {
+	color: #d45aa0;
+}
+
+body[data-section="tailwind"] #lesson-title {
+	color: #1aafb8;
+}
+
 /* Section and Reference footer - override landing-footer styles */
 .section-footer.landing-footer,
 .reference-footer.landing-footer {