Add hover effects to cards and navigation bar for visual appeal

Updated `styles.css` to include hover transitions for sponsor and contact cards, changing their border color to baby blue. Added a gradient border effect to the navigation bar on hover using CSS.

Replit-Commit-Author: Agent
Replit-Commit-Session-Id: 75bceff7-98f2-4f6e-ae8e-e735399a1fe8
Replit-Commit-Checkpoint-Type: full_checkpoint
Replit-Commit-Event-Id: 4b09b314-9c6c-458e-ba49-64a6c35a7e9b
Replit-Commit-Screenshot-Url: https://storage.googleapis.com/screenshot-production-us-central1/d0a1d46d-d203-4308-bc6a-312ac7c0243b/75bceff7-98f2-4f6e-ae8e-e735399a1fe8/vUHpl97

static/css/styles.css

@@ -99,6 +99,15 @@ body::after {
     -webkit-backdrop-filter: blur(12px);
     border: 1px solid rgba(255, 255, 255, 0.08);
     border-radius: 16px;
+    transition: border 0.3s ease;
+}
+
+.navbar-inner:hover {
+    border: 1px solid transparent;
+    background-image: linear-gradient(rgba(0, 0, 0, 0.5), rgba(0, 0, 0, 0.5)), 
+                      linear-gradient(90deg, #3b82f6, #8b5cf6);
+    background-origin: border-box;
+    background-clip: padding-box, border-box;
 }
 
 .navbar-logo {
@@ -899,6 +908,7 @@ hr {
 .card-sponsors:hover {
     transform: translateY(-8px);
     box-shadow: 0 20px 40px rgba(255, 255, 255, 0.05);
+    border-color: #3b82f6;
 }
 
 .card-content,