.sidebar {
    min-height: 100vh;
    background: #2c3e50;
    box-shadow: 2px 0 5px rgba(0,0,0,0.1);
}

.sidebar .nav-link {
    color: #ecf0f1;
    padding: 12px 20px;
    transition: all 0.3s;
}

.sidebar .nav-link:hover {
    background: #34495e;
    padding-left: 25px;
}

.sidebar .nav-link.active {
    background: #3498db;
    border-left: 4px solid #2980b9;
}

.stat-card {
    border-left: 4px solid #3498db;
    transition: transform 0.3s;
}

.stat-card:hover {
    transform: translateY(-5px);
    box-shadow: 0 4px 8px rgba(0,0,0,0.1);
}

.stat-card.danger {
    border-left-color: #e74c3c;
}

.stat-card.warning {
    border-left-color: #f39c12;
}

.stat-card.success {
    border-left-color: #27ae60;
}

.loading {
    display: inline-block;
    width: 20px;
    height: 20px;
    border: 3px solid rgba(0,0,0,.1);
    border-radius: 50%;
    border-top-color: #3498db;
    animation: spin 1s ease-in-out infinite;
}

@keyframes spin {
    to { transform: rotate(360deg); }
}