body {
    background-color: #f4f6f9;
    font-family: 'Segoe UI', system-ui, sans-serif;
}
.sidebar {
    width: 280px;
    min-height: 100vh;
    position: sticky;
    top: 0;
    flex-shrink: 0;
}
.sidebar .nav-link {
    white-space: nowrap;
    font-size: 0.95rem;
    padding: 0.55rem 0.75rem;
}
.sidebar .nav-link.active {
    background-color: rgba(255,255,255,.2);
    font-weight: 600;
}
.sidebar .nav-link:hover {
    background-color: rgba(255,255,255,.1);
}
.card-summary {
    border: none;
    border-radius: 14px;
    color: #fff;
    box-shadow: 0 4px 10px rgba(0,0,0,.08);
}
.card-summary .display-6 { font-weight: 700; }
.login-wrapper {
    min-height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
    background: linear-gradient(135deg,#1d3557,#457b9d);
}
.login-card {
    max-width: 420px;
    width: 100%;
    border-radius: 16px;
    border: none;
}
#reader { width: 100%; max-width: 480px; margin: auto; }

@media (max-width: 767.98px) {
    .sidebar {
        position: fixed;
        left: -300px;
        z-index: 1050;
        transition: left .25s ease;
        height: 100%;
    }
    .sidebar.show { left: 0; }
}

@media print {
    .sidebar, .btn, .no-print { display: none !important; }
    main { padding: 0 !important; width: 100% !important; }
}