feat(home): redesign homepage with refined visuals and improved layout flow

- Enhanced hero section with updated typography, animations, and gradient backgrounds.
- Replaced single featured project with dynamic multi-project filtering.
- Improved section transitions and added cohesive hover effects for interactivity.
- Updated CSS variables for softer background colors and unified design language.
- Added responsive refinements for better experience across devices.

src/styles/global.css

@@ -44,7 +44,7 @@
 
 :root {
   --radius: 0.75rem;
-  --background: #F8FAFC;
+  --background: #F1F5F9; /* 更柔和的蓝灰色，不再是纯白或过于扎眼的浅色 */
   --foreground: #1E293B;
   --card: #FFFFFF;
   --card-foreground: #1E293B;