Modern dark mode UI overhaul

frontend/src/components/Layout.css

@@ -2,64 +2,174 @@
   min-height: 100vh;
   display: flex;
   flex-direction: column;
+  background: var(--bg-primary);
 }
 
+/* Header */
 .header {
-  background-color: var(--primary);
-  color: white;
-  padding: 1rem 0;
-  box-shadow: 0 2px 4px rgba(0,0,0,0.1);
+  background: var(--bg-secondary);
+  border-bottom: 1px solid var(--border-primary);
+  padding: 0;
+  position: sticky;
+  top: 0;
+  z-index: 100;
+  backdrop-filter: blur(12px);
+  background: rgba(17, 17, 19, 0.85);
 }
 
 .header-content {
   display: flex;
   justify-content: space-between;
   align-items: center;
+  height: 64px;
 }
 
+/* Logo */
 .logo {
   display: flex;
   align-items: center;
-  gap: 0.5rem;
-  color: white;
-  font-size: 1.5rem;
-  font-weight: bold;
+  gap: 12px;
+  color: var(--text-primary);
+  font-size: 1.25rem;
+  font-weight: 600;
   text-decoration: none;
+  transition: opacity var(--transition-fast);
 }
 
 .logo:hover {
-  text-decoration: none;
+  opacity: 0.9;
+  color: var(--text-primary);
 }
 
 .logo-icon {
-  font-size: 2rem;
+  display: flex;
+  align-items: center;
+  justify-content: center;
+  width: 40px;
+  height: 40px;
+  background: var(--accent-gradient);
+  border-radius: var(--radius-md);
+  color: white;
+  box-shadow: var(--shadow-glow);
 }
 
+.logo-text {
+  letter-spacing: -0.02em;
+}
+
+/* Navigation */
 .nav {
   display: flex;
-  gap: 1.5rem;
+  gap: 8px;
 }
 
 .nav a {
-  color: white;
-  opacity: 0.9;
+  display: flex;
+  align-items: center;
+  gap: 8px;
+  padding: 8px 16px;
+  color: var(--text-primary);
+  font-size: 0.875rem;
+  font-weight: 500;
+  border-radius: var(--radius-md);
+  transition: all var(--transition-fast);
 }
 
 .nav a:hover {
-  opacity: 1;
-  text-decoration: none;
+  color: var(--text-primary);
+  background: var(--bg-hover);
 }
 
+.nav a.active {
+  color: var(--accent-primary);
+  background: rgba(16, 185, 129, 0.1);
+}
+
+.nav a svg {
+  opacity: 0.8;
+}
+
+.nav a:hover svg,
+.nav a.active svg {
+  opacity: 1;
+}
+
+.nav-link-muted {
+  opacity: 0.7;
+}
+
+/* Main content */
 .main {
   flex: 1;
-  padding: 2rem 0;
+  padding: 32px 0 64px;
 }
 
+/* Footer */
 .footer {
-  background-color: var(--primary-dark);
-  color: white;
-  padding: 1rem 0;
-  text-align: center;
-  opacity: 0.9;
+  background: var(--bg-secondary);
+  border-top: 1px solid var(--border-primary);
+  padding: 24px 0;
+}
+
+.footer-content {
+  display: flex;
+  justify-content: space-between;
+  align-items: center;
+}
+
+.footer-brand {
+  display: flex;
+  align-items: center;
+  gap: 12px;
+}
+
+.footer-logo {
+  font-weight: 600;
+  color: var(--text-primary);
+}
+
+.footer-tagline {
+  color: var(--text-secondary);
   font-size: 0.875rem;
 }
+
+.footer-links {
+  display: flex;
+  gap: 24px;
+}
+
+.footer-links a {
+  color: var(--text-secondary);
+  font-size: 0.875rem;
+  transition: color var(--transition-fast);
+}
+
+.footer-links a:hover {
+  color: var(--text-primary);
+}
+
+/* Responsive */
+@media (max-width: 640px) {
+  .header-content {
+    height: 56px;
+  }
+
+  .logo-text {
+    display: none;
+  }
+
+  .nav a span {
+    display: none;
+  }
+
+  .footer-content {
+    flex-direction: column;
+    gap: 16px;
+    text-align: center;
+  }
+
+  .footer-brand {
+    flex-direction: column;
+    gap: 4px;
+  }
+}