body { background-color: #f4f6f9; }
.sidebar { min-height: 100vh; background-color: #343a40; }
.sidebar .nav-link { color: #adb5bd; padding: .5rem 1rem; }
.sidebar .nav-link:hover, .sidebar .nav-link.active { color: #fff; background-color: rgba(255,255,255,.1); border-radius: .25rem; }
.sidebar .nav-section { font-size: .7rem; text-transform: uppercase; letter-spacing: .08em; color: #6c757d; padding: .5rem 1rem; margin-top: .5rem; }
.sidebar .sidebar-brand { padding: 1rem; font-size: 1.1rem; font-weight: 700; color: #fff; border-bottom: 1px solid rgba(255,255,255,.1); }
.main-content { padding: 1.5rem; }
.stat-card { border-left: 4px solid; }
.stat-card.blue { border-color: #0d6efd; }
.stat-card.green { border-color: #198754; }
.stat-card.yellow { border-color: #ffc107; }
.stat-card.red { border-color: #dc3545; }
.attendance-P { background-color: #d1e7dd; }
.attendance-A { background-color: #f8d7da; }
.attendance-L { background-color: #fff3cd; }
@media (max-width: 768px) { .sidebar { min-height: auto; } }