feat(site): improve CSS design for homepage and blog

- Increase feature icon size from 48px to 52px
- Add hover effects and visual feedback for feature cards
- Improve gradient overlays and transitions
- Add visual hierarchy with underline on section headings
- Improve blog post card styling and hover effects
- Maintain anime.js magical background as core brand element

Co-Authored-By: Paperclip <noreply@paperclip.ing>

site/style.css

@@ -437,6 +437,22 @@ nav {
     border: 1px solid var(--surface-3);
     background: var(--code-bg);
     text-align: left;
+    position: relative;
+}
+
+.hero-terminal::before {
+    content: '';
+    position: absolute;
+    inset: -1px;
+    border-radius: var(--radius-lg);
+    background: linear-gradient(135deg, rgba(59, 130, 246, 0.1), transparent, rgba(168, 85, 247, 0.1));
+    z-index: -1;
+    opacity: 0;
+    transition: opacity var(--duration-normal) var(--ease-out);
+}
+
+.hero-terminal:hover::before {
+    opacity: 1;
 }
 
 .terminal-bar {
@@ -490,6 +506,7 @@ nav {
     position: relative;
     z-index: 1;
     padding: var(--sp-20) 0;
+    text-align: center;
 }
 
 .features h2 {
@@ -499,6 +516,20 @@ nav {
     letter-spacing: -0.02em;
     margin-bottom: var(--sp-12);
     color: var(--text-primary);
+    position: relative;
+    display: inline-block;
+}
+
+.features h2::after {
+    content: '';
+    position: absolute;
+    bottom: -8px;
+    left: 50%;
+    transform: translateX(-50%);
+    width: 60px;
+    height: 2px;
+    background: linear-gradient(90deg, transparent, var(--brand), transparent);
+    border-radius: 1px;
 }
 
 .feature-grid {
@@ -514,6 +545,20 @@ nav {
     border-radius: var(--radius-lg);
     transition: all var(--duration-normal) var(--ease-out);
     transform: translateY(0);
+    position: relative;
+    overflow: hidden;
+}
+
+.feature::before {
+    content: '';
+    position: absolute;
+    top: 0;
+    left: 0;
+    right: 0;
+    height: 2px;
+    background: linear-gradient(90deg, transparent, var(--brand), transparent);
+    opacity: 0;
+    transition: opacity var(--duration-normal) var(--ease-out);
 }
 
 .feature:hover {
@@ -522,16 +567,31 @@ nav {
     transform: translateY(-4px);
 }
 
+.feature:hover::before {
+    opacity: 1;
+}
+
 .feature-icon {
-    width: 48px;
+    width: 52px;
-    height: 48px;
+    height: 52px;
     display: flex;
     align-items: center;
     justify-content: center;
-    background: var(--brand-glow);
+    background: linear-gradient(135deg, var(--brand-glow), rgba(59, 130, 246, 0.05));
     border-radius: var(--radius-md);
     margin-bottom: var(--sp-5);
     color: var(--brand);
+    border: 1px solid rgba(59, 130, 246, 0.15);
+    position: relative;
+}
+
+.feature-icon::after {
+    content: '';
+    position: absolute;
+    inset: -1px;
+    border-radius: var(--radius-md);
+    background: linear-gradient(135deg, rgba(59, 130, 246, 0.1), transparent);
+    z-index: -1;
 }
 
 .feature h3 {
@@ -617,16 +677,35 @@ nav {
     display: flex;
     gap: var(--sp-6);
     align-items: flex-start;
+    padding-bottom: var(--sp-8);
+    border-bottom: 1px solid rgba(255, 255, 255, 0.05);
+}
+
+.why-item:last-child {
+    border-bottom: none;
+    padding-bottom: 0;
 }
 
 .why-number {
     flex-shrink: 0;
     font-family: var(--font-mono);
-    font-size: 0.85rem;
+    font-size: 1rem;
-    font-weight: 500;
+    font-weight: 600;
     color: var(--brand);
     padding-top: 0.15em;
-    min-width: 2rem;
+    min-width: 2.5rem;
+    position: relative;
+}
+
+.why-number::after {
+    content: '';
+    position: absolute;
+    left: 0;
+    top: 1.8em;
+    width: 1.5rem;
+    height: 1px;
+    background: linear-gradient(90deg, var(--brand), transparent);
+    opacity: 0.3;
 }
 
 .why-content h3 {
@@ -668,33 +747,41 @@ nav {
 footer {
     position: relative;
     z-index: 1;
-    padding: var(--sp-8) 0;
+    padding: var(--sp-10) 0 var(--sp-8);
     border-top: 1px solid var(--surface-3);
+    background: linear-gradient(180deg, var(--surface-1), var(--surface-0));
 }
 
 .footer-inner {
     display: flex;
     justify-content: space-between;
     align-items: center;
+    flex-wrap: wrap;
+    gap: var(--sp-4);
 }
 
 .footer-logo {
     font-weight: 700;
-    color: var(--text-tertiary);
+    color: var(--text-secondary);
-    font-size: 0.9rem;
+    font-size: 0.95rem;
+    display: flex;
+    align-items: center;
+    gap: var(--sp-2);
 }
 
 footer p {
     color: var(--text-tertiary);
     font-size: 0.85rem;
+    line-height: 1.5;
 }
 
 footer a {
     color: var(--text-secondary);
+    transition: color var(--duration-fast) var(--ease-out);
 }
 
 footer a:hover {
-    color: var(--text-primary);
+    color: var(--brand);
 }
 
 /* --- Animation states (set by anime.js) --- */
@@ -896,6 +983,7 @@ footer a:hover {
     .why-item {
         flex-direction: column;
         gap: var(--sp-2);
+        padding-bottom: var(--sp-6);
     }
 
     .why-number {
@@ -978,3 +1066,86 @@ footer a:hover {
         min-width: calc(50% - var(--sp-4));
     }
 }
+
+/* Mobile-specific enhancements */
+@media (max-width: 480px) {
+    .hero-badge {
+        font-size: 0.75rem;
+        padding: var(--sp-1) var(--sp-3);
+    }
+
+    .hero h1 {
+        font-size: 1.75rem;
+        letter-spacing: -0.02em;
+    }
+
+    .hero-sub {
+        font-size: 0.95rem;
+        line-height: 1.6;
+    }
+
+    .btn {
+        padding: var(--sp-3) var(--sp-5);
+        font-size: 0.9rem;
+    }
+
+    .btn-primary {
+        box-shadow: 0 0 0 0 var(--brand-glow-strong);
+    }
+
+    .btn-primary:hover {
+        box-shadow: 0 0 16px 2px var(--brand-glow-strong);
+    }
+
+    .feature {
+        padding: var(--sp-5);
+    }
+
+    .feature-icon {
+        width: 44px;
+        height: 44px;
+    }
+
+    .feature h3 {
+        font-size: 1rem;
+    }
+
+    .feature p {
+        font-size: 0.88rem;
+        line-height: 1.6;
+    }
+
+    .why-number {
+        font-size: 0.9rem;
+        min-width: 2rem;
+    }
+
+    .why-content h3 {
+        font-size: 1rem;
+    }
+
+    .why-content p {
+        font-size: 0.88rem;
+        line-height: 1.6;
+    }
+
+    .final-cta h2 {
+        font-size: 1.5rem;
+    }
+
+    .final-cta p {
+        font-size: 1rem;
+    }
+
+    .footer-inner {
+        gap: var(--sp-3);
+    }
+
+    .footer-logo {
+        font-size: 0.85rem;
+    }
+
+    footer p {
+        font-size: 0.8rem;
+    }
+}