:root {
    --primary: #7b1e2b;
    --primary-hover: #661823;
    --primary-soft: #fdf2f4;
    --focus-ring: rgba(123, 30, 43, 0.18);
    --danger: #ef4444;
    --danger-hover: #dc2626;
    --background: #f8fafc;
    --surface: #ffffff;
    --text-main: #0f172a;
    --text-muted: #64748b;
    --border: #e2e8f0;
    --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.05);
    --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.1), 0 2px 4px -1px rgba(0, 0, 0, 0.06);
    --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.1), 0 4px 6px -2px rgba(0, 0, 0, 0.05);
    --radius-md: 0.5rem;
    --radius-lg: 0.75rem;
}

* {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
}

body {
    font-family: 'Inter', system-ui, sans-serif;
    background-color: var(--background);
    color: var(--text-main);
    line-height: 1.5;
    -webkit-font-smoothing: antialiased;
}

.container {
    max-width: 1000px;
    margin: 0 auto;
    padding: 0 20px 40px;
}

/* Navigation */
nav {
    background: rgba(255, 255, 255, 0.8);
    backdrop-filter: blur(12px);
    -webkit-backdrop-filter: blur(12px);
    position: sticky;
    top: 0;
    z-index: 50;
    display: flex;
    align-items: center;
    gap: 20px;
    padding: 15px 30px;
    border-bottom: 1px solid rgba(226, 232, 240, 0.6);
    margin-bottom: 30px;
    box-shadow: var(--shadow-sm);
}

nav a {
    text-decoration: none;
    color: var(--text-muted);
    font-weight: 500;
    transition: color 0.2s ease, transform 0.2s ease;
}

nav a:hover {
    color: var(--primary);
}

a:focus-visible,
button:focus-visible,
input:focus-visible {
    outline: 3px solid var(--focus-ring);
    outline-offset: 2px;
}

nav a strong {
    color: var(--text-main);
    font-size: 1.25rem;
    font-weight: 700;
    letter-spacing: -0.025em;
}

nav .spacer {
    flex-grow: 1;
}

nav .user-info {
    color: var(--text-muted);
    font-weight: 500;
    font-size: 0.95em;
    display: flex;
    align-items: center;
    gap: 8px;
}

/* Buttons */
.btn {
    background-color: var(--primary);
    color: white;
    border: none;
    padding: 8px 16px;
    font-size: 0.95rem;
    font-weight: 500;
    cursor: pointer;
    text-decoration: none;
    border-radius: var(--radius-md);
    transition: all 0.2s ease;
    display: inline-flex;
    align-items: center;
    justify-content: center;
    box-shadow: var(--shadow-sm);
}

.btn:hover {
    background-color: var(--primary-hover);
    transform: translateY(-1px);
    box-shadow: var(--shadow-md);
}

.btn:active {
    transform: translateY(0);
}

.btn-sm {
    padding: 6px 12px;
    font-size: 0.85rem;
}

.btn-outline {
    background: transparent;
    color: var(--primary);
    border: 1px solid var(--primary);
    box-shadow: none;
}

.btn-outline:hover {
    color: #fff;
    border-color: var(--primary-hover);
    background-color: var(--primary-hover);
}

.btn-danger {
    background-color: var(--danger);
}

.btn-danger:hover {
    background-color: var(--danger-hover);
}

/* Tables (for class lists, etc) */
.table-container {
    background: var(--surface);
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-md);
    overflow: hidden;
    margin-bottom: 30px;
    border: 1px solid var(--border);
}

table {
    width: 100%;
    border-collapse: collapse;
    text-align: left;
}

th {
    background-color: #f8fafc;
    color: var(--text-muted);
    font-weight: 600;
    font-size: 0.85rem;
    text-transform: uppercase;
    letter-spacing: 0.05em;
    padding: 16px 20px;
    border-bottom: 1px solid var(--border);
}

td {
    padding: 16px 20px;
    border-bottom: 1px solid var(--border);
    vertical-align: middle;
}

tr:last-child td {
    border-bottom: none;
}

tr:hover td {
    background-color: #f8fafc;
}

tr.full-class td {
    color: var(--text-muted);
    background-color: #f1f5f9;
}

/* Messages / Alerts */
.messages {
    list-style: none;
    margin-bottom: 30px;
    display: flex;
    flex-direction: column;
    gap: 10px;
}

.messages li {
    padding: 12px 20px;
    border-radius: var(--radius-md);
    font-weight: 500;
    animation: slideIn 0.3s ease;
    box-shadow: var(--shadow-sm);
}

@keyframes slideIn {
    from {
        opacity: 0;
        transform: translateY(-10px);
    }

    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.messages .success {
    background-color: #dcfce7;
    color: #166534;
    border-left: 4px solid #22c55e;
}

.messages .error {
    background-color: #fee2e2;
    color: #991b1b;
    border-left: 4px solid #ef4444;
}

.messages .warning {
    background-color: #fef9c3;
    color: #854d0e;
    border-left: 4px solid #eab308;
}

.messages .info {
    background-color: var(--primary-soft);
    color: #6b1d29;
    border-left: 4px solid var(--primary);
}

/* Typography */
h1,
h2,
h3 {
    color: var(--text-main);
    margin-bottom: 20px;
    font-weight: 700;
    letter-spacing: -0.025em;
}

h1 {
    font-size: 2.25rem;
}

h2 {
    font-size: 1.875rem;
}

a.link {
    color: var(--primary);
    text-decoration: none;
    font-weight: 500;
}

a.link:hover {
    text-decoration: underline;
}

/* Auth Forms & Cards */
.auth-card {
    background: var(--surface);
    max-width: 440px;
    margin: 60px auto;
    padding: 40px;
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-lg);
    border: 1px solid rgba(226, 232, 240, 0.8);
}

.auth-card h1 {
    text-align: center;
    margin-bottom: 10px;
    font-size: 1.75rem;
}

.auth-card p.subtitle {
    text-align: center;
    color: var(--text-muted);
    margin-bottom: 30px;
}

.form-group p {
    margin-bottom: 20px;
}

.form-group label {
    display: block;
    margin-bottom: 8px;
    font-weight: 500;
    font-size: 0.95rem;
    color: var(--text-main);
}

.form-group input[type="text"],
.form-group input[type="password"],
.form-group input[type="email"],
.form-group input[type="number"],
.form-group input[type="date"],
.form-group input[type="datetime-local"],
.form-group select,
.form-group textarea {
    width: 100%;
    padding: 12px 16px;
    border: 1px solid var(--border);
    border-radius: var(--radius-md);
    font-size: 1rem;
    font-family: 'Inter', sans-serif;
    transition: all 0.2s;
    background-color: #f8fafc;
}

.form-group input:focus,
.form-group select:focus,
.form-group textarea:focus {
    outline: none;
    border-color: var(--primary);
    box-shadow: 0 0 0 3px var(--focus-ring);
    background-color: var(--surface);
}

.form-group .helptext {
    display: block;
    font-size: 0.8rem;
    color: var(--text-muted);
    margin-top: 6px;
}

.form-group ul.errorlist {
    list-style: none;
    color: var(--danger);
    font-size: 0.85rem;
    margin-top: 6px;
    padding: 0;
    background: #fee2e2;
    padding: 6px 10px;
    border-radius: 4px;
}

.auth-card .btn {
    width: 100%;
    padding: 12px;
    font-size: 1rem;
    margin-top: 10px;
}

.auth-card .footer-text {
    text-align: center;
    margin-top: 25px;
    font-size: 0.95rem;
    color: var(--text-muted);
}

.auth-card .footer-text a {
    color: var(--primary);
    font-weight: 600;
    text-decoration: none;
}

/* Cards */
.cards-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
    gap: 20px;
    margin-bottom: 30px;
}

.card {
    background: var(--surface);
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-sm);
    border: 1px solid var(--border);
    padding: 24px;
    display: flex;
    flex-direction: column;
    transition: transform 0.2s ease, box-shadow 0.2s ease;
}

.card:hover {
    transform: translateY(-2px);
    box-shadow: var(--shadow-md);
}

.card-header {
    display: flex;
    justify-content: space-between;
    align-items: flex-start;
    margin-bottom: 15px;
    gap: 12px;
}

.card-title {
    font-size: 1.25rem;
    font-weight: 700;
    color: var(--text-main);
    text-decoration: none;
    line-height: 1.3;
}

.card-title:hover {
    color: var(--primary);
}

.card-body {
    flex-grow: 1;
}

.card-detail {
    display: flex;
    align-items: center;
    gap: 8px;
    color: var(--text-muted);
    font-size: 0.95rem;
    margin-bottom: 10px;
}

.card-detail svg {
    flex-shrink: 0;
    color: var(--text-muted);
}

.card-footer {
    margin-top: 20px;
    padding-top: 15px;
    border-top: 1px solid var(--border);
    display: flex;
    justify-content: space-between;
    align-items: center;
    gap: 10px;
    flex-wrap: wrap;
}

/* Detail Layout */
.detail-layout {
    display: grid;
    grid-template-columns: minmax(0, 2fr) minmax(0, 1fr);
    gap: 30px;
    margin-bottom: 30px;
}

@media (max-width: 768px) {
    .detail-layout {
        grid-template-columns: 1fr;
    }

    .detail-sidebar {
        position: static;
    }
}

.detail-main {
    background: var(--surface);
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-sm);
    border: 1px solid var(--border);
    padding: 30px;
}

.detail-sidebar {
    background: var(--surface);
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-sm);
    border: 1px solid var(--border);
    padding: 24px;
    height: fit-content;
    position: sticky;
    top: 100px;
}

.info-group {
    margin-bottom: 20px;
}

.info-group:last-child {
    margin-bottom: 0;
}

.info-label {
    display: block;
    font-size: 0.8rem;
    color: var(--text-muted);
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.05em;
    margin-bottom: 4px;
}

.info-value {
    font-size: 1.05rem;
    color: var(--text-main);
    font-weight: 500;
}

/* Badges */
.badge {
    display: inline-flex;
    align-items: center;
    padding: 4px 10px;
    border-radius: 9999px;
    font-size: 0.75rem;
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.05em;
}

.badge-success {
    background-color: #dcfce7;
    color: #166534;
}

.badge-danger {
    background-color: #fee2e2;
    color: #991b1b;
}

.badge-secondary {
    background-color: #f1f5f9;
    color: #475569;
}

/* Header action bar */
.page-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 30px;
}

.page-header h1 {
    margin-bottom: 0;
}

@media (max-width: 768px) {
    nav {
        padding: 12px 16px;
        gap: 12px;
    }

    nav .user-info {
        width: 100%;
        order: 10;
        justify-content: flex-end;
    }

    .container {
        padding: 0 14px 30px;
    }

    .auth-card {
        margin: 30px auto;
        padding: 24px;
    }

    h1 {
        font-size: 1.8rem;
    }

    .page-header {
        flex-direction: column;
        align-items: flex-start;
        gap: 12px;
    }

    .cards-grid {
        grid-template-columns: 1fr;
    }
}