body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
}

.sidebar {
    position: fixed;
    top: 56px;
    bottom: 0;
    left: 0;
    z-index: 100;
    padding: 48px 0 0;
    box-shadow: inset -1px 0 0 rgba(0, 0, 0, .1);
    overflow-y: auto;
}

.sidebar .nav-link {
    font-weight: 500;
    color: #333;
    padding: 0.5rem 1rem;
}

.sidebar .nav-link:hover {
    color: #0d6efd;
    background-color: rgba(13, 110, 253, 0.1);
}

.sidebar .nav-link.active {
    color: #0d6efd;
}

.sidebar-heading {
    font-size: .75rem;
    text-transform: uppercase;
}

main {
    margin-top: 56px;
}

.system-card {
    transition: transform 0.2s;
}

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

.jumbotron {
    background: linear-gradient(135deg, #f8f9fa 0%, #e9ecef 100%);
}

@media (max-width: 767.98px) {
    .sidebar {
        top: 0;
        padding-top: 56px;
        position: relative;
    }
    
    main {
        margin-top: 0;
    }
}