:root {
    --bg: #f7fafc;
    --surface: #ffffff;
    --surface-soft: #f1f5f9;
    --surface-tint: #eef6ff;
    --sidebar: #102033;
    --sidebar-soft: #172b42;
    --primary: #2563eb;
    --primary-dark: #1d4ed8;
    --primary-soft: #dbeafe;
    --accent: #0f766e;
    --accent-soft: #ccfbf1;
    --warning: #b45309;
    --warning-soft: #fef3c7;
    --danger: #dc2626;
    --danger-soft: #fee2e2;
    --success: #15803d;
    --success-soft: #dcfce7;
    --text: #172033;
    --muted: #64748b;
    --faint: #94a3b8;
    --line: #dbe4ee;
    --line-soft: #e8eef5;
    --radius: 16px;
    --radius-sm: 10px;
    --shadow: 0 18px 48px rgba(15, 32, 51, 0.12);
    --shadow-soft: 0 8px 24px rgba(15, 32, 51, 0.08);
    --focus: 0 0 0 4px rgba(37, 99, 235, 0.16);
}

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

body {
    min-height: 100vh;
    background: var(--bg);
    color: var(--text);
    font-family: "Fira Sans", "Segoe UI", "Microsoft YaHei", system-ui, sans-serif;
    font-size: 15px;
    line-height: 1.6;
}

a {
    color: var(--primary);
    text-decoration: none;
}

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

.skip-link {
    position: fixed;
    top: -48px;
    left: 16px;
    z-index: 1000;
    padding: 8px 12px;
    border-radius: var(--radius-sm);
    background: var(--text);
    color: #fff;
}

.skip-link:focus {
    top: 16px;
}

.app-shell {
    min-height: 100vh;
    display: grid;
    grid-template-columns: 260px minmax(0, 1fr);
}

.sidebar {
    position: sticky;
    top: 0;
    height: 100vh;
    padding: 22px 18px;
    background: linear-gradient(180deg, var(--sidebar), #0b1624);
    color: #e5eef8;
    display: flex;
    flex-direction: column;
    gap: 28px;
}

.brand {
    display: flex;
    align-items: center;
    gap: 12px;
    color: inherit;
}

.brand:hover {
    color: inherit;
}

.brand-mark {
    width: 42px;
    height: 42px;
    display: inline-flex;
    align-items: center;
    justify-content: center;
    border-radius: 14px;
    background: linear-gradient(135deg, #60a5fa, #34d399);
    color: #fff;
    font-weight: 800;
    font-size: 18px;
    box-shadow: 0 10px 24px rgba(52, 211, 153, 0.22);
}

.brand strong {
    display: block;
    font-size: 17px;
    line-height: 1.2;
}

.brand small {
    display: block;
    margin-top: 2px;
    color: #9fb3ca;
    font-size: 12px;
}

.side-nav {
    display: flex;
    flex-direction: column;
    gap: 8px;
}

.side-nav a {
    display: flex;
    align-items: center;
    min-height: 42px;
    padding: 10px 12px;
    border-radius: 12px;
    color: #b9c8da;
    font-weight: 600;
    transition: background 0.2s ease, color 0.2s ease;
}

.side-nav a:hover {
    background: rgba(255, 255, 255, 0.08);
    color: #fff;
}

.side-nav a.active {
    background: #fff;
    color: var(--sidebar);
}

.workspace {
    min-width: 0;
    display: flex;
    flex-direction: column;
}

.topbar {
    position: sticky;
    top: 0;
    z-index: 50;
    min-height: 72px;
    padding: 16px 32px;
    border-bottom: 1px solid var(--line-soft);
    background: rgba(247, 250, 252, 0.88);
    backdrop-filter: blur(16px);
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 18px;
}

.topbar strong {
    display: block;
    font-size: 18px;
}

.eyebrow {
    display: block;
    color: var(--muted);
    font-size: 12px;
    font-weight: 700;
    letter-spacing: 0.08em;
}

.topbar-actions {
    display: flex;
    align-items: center;
    gap: 10px;
    flex-wrap: wrap;
    justify-content: flex-end;
}

.utility-link {
    min-height: 34px;
    display: inline-flex;
    align-items: center;
    padding: 7px 12px;
    border: 1px solid var(--line);
    border-radius: 999px;
    background: var(--surface);
    color: var(--text);
    font-size: 13px;
    font-weight: 700;
}

.container {
    width: min(100%, 1180px);
    margin: 0 auto;
    padding: 28px 32px;
}

.container.narrow {
    max-width: 820px;
}

.flash-container {
    padding-bottom: 0;
}

.page-header {
    margin-bottom: 22px;
    padding: 26px;
    border-radius: 24px;
    background:
        radial-gradient(circle at top right, rgba(37, 99, 235, 0.13), transparent 36%),
        linear-gradient(135deg, #ffffff, #f2f7ff);
    border: 1px solid var(--line-soft);
}

.page-header h1 {
    color: var(--text);
    font-size: 30px;
    line-height: 1.2;
    font-weight: 800;
}

.page-header p {
    margin-top: 8px;
    color: var(--muted);
    font-size: 15px;
}

.page-header[style] {
    display: flex !important;
    justify-content: space-between !important;
    align-items: center !important;
    gap: 16px;
}

.card {
    background: var(--surface);
    border: 1px solid var(--line-soft);
    border-radius: var(--radius);
    box-shadow: var(--shadow-soft);
    overflow: hidden;
}

a.card {
    color: var(--text);
    transition: transform 0.2s ease, box-shadow 0.2s ease, border-color 0.2s ease;
}

a.card:hover {
    transform: translateY(-2px);
    border-color: #bfdbfe;
    box-shadow: var(--shadow);
}

.card-header {
    padding: 18px 20px;
    border-bottom: 1px solid var(--line-soft);
    background: #fbfdff;
    font-size: 16px;
    font-weight: 800;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.card-body {
    padding: 20px;
}

.card-footer {
    padding: 14px 20px;
    border-top: 1px solid var(--line-soft);
    background: var(--surface-soft);
}

.stats-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(190px, 1fr));
    gap: 16px;
    margin-bottom: 22px;
}

.stat-card {
    position: relative;
    min-height: 132px;
    padding: 20px;
    border: 1px solid var(--line-soft);
    border-radius: 20px;
    background: var(--surface);
    box-shadow: var(--shadow-soft);
    overflow: hidden;
}

.stat-card::after {
    content: "";
    position: absolute;
    right: -26px;
    top: -28px;
    width: 92px;
    height: 92px;
    border-radius: 999px;
    background: var(--primary-soft);
}

.stat-card.success::after { background: var(--accent-soft); }
.stat-card.warning::after { background: var(--warning-soft); }
.stat-card.danger::after { background: var(--danger-soft); }

.stat-label {
    color: var(--muted);
    font-size: 13px;
    font-weight: 700;
}

.stat-value {
    position: relative;
    margin-top: 8px;
    font-size: 34px;
    font-weight: 850;
    line-height: 1;
}

.stat-card.primary .stat-value { color: var(--primary); }
.stat-card.success .stat-value { color: var(--accent); }
.stat-card.warning .stat-value { color: var(--warning); }
.stat-card.danger .stat-value { color: var(--danger); }

.dashboard-grid {
    display: grid;
    grid-template-columns: minmax(260px, 0.8fr) minmax(340px, 1.2fr);
    gap: 16px;
}

.action-grid {
    display: grid;
    grid-template-columns: repeat(3, minmax(0, 1fr));
    gap: 16px;
}

.action-card {
    min-height: 150px;
    padding: 22px;
    display: flex;
    flex-direction: column;
    justify-content: center;
}

.list-row {
    padding: 12px 0;
    border-bottom: 1px solid var(--line-soft);
}

.list-row:last-child {
    border-bottom: 0;
}

.muted-text {
    color: var(--muted) !important;
    font-size: 13px !important;
}

.table-wrapper {
    width: 100%;
    overflow-x: auto;
}

table {
    width: 100%;
    border-collapse: collapse;
    font-size: 14px;
}

th,
td {
    padding: 13px 14px;
    border-bottom: 1px solid var(--line-soft);
    text-align: left;
    vertical-align: middle;
}

th {
    background: #f8fbff;
    color: var(--muted);
    font-size: 12px;
    font-weight: 800;
    white-space: nowrap;
}

tr:hover td {
    background: #fbfdff;
}

.btn {
    min-height: 40px;
    padding: 9px 16px;
    border: 1px solid transparent;
    border-radius: 999px;
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 6px;
    cursor: pointer;
    font-family: inherit;
    font-size: 14px;
    font-weight: 800;
    line-height: 1.2;
    transition: background 0.2s ease, border-color 0.2s ease, transform 0.2s ease;
}

.btn:hover {
    text-decoration: none;
}

.btn:active {
    transform: translateY(1px);
}

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

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

.btn-success {
    background: var(--accent);
    color: #fff;
}

.btn-warning {
    background: var(--warning);
    color: #fff;
}

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

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

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

.btn-sm {
    min-height: 32px;
    padding: 6px 11px;
    font-size: 12px;
}

.btn-block {
    width: 100%;
}

.btn-group {
    display: flex;
    gap: 8px;
    flex-wrap: wrap;
}

.btn-group[style*="column"] .btn {
    width: 100%;
}

.form-group {
    margin-bottom: 16px;
}

.form-group label {
    display: block;
    margin-bottom: 7px;
    color: var(--text);
    font-size: 13px;
    font-weight: 800;
}

.form-control {
    width: 100%;
    min-height: 42px;
    padding: 9px 12px;
    border: 1px solid var(--line);
    border-radius: 12px;
    background: #fff;
    color: var(--text);
    font-family: inherit;
    font-size: 14px;
    transition: border-color 0.2s ease, box-shadow 0.2s ease;
}

.form-control:focus,
.btn:focus-visible,
a:focus-visible,
button:focus-visible {
    outline: none;
    border-color: var(--primary);
    box-shadow: var(--focus);
}

textarea.form-control {
    min-height: 120px;
    resize: vertical;
}

.form-row {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 16px;
}

.form-actions {
    display: flex;
    gap: 10px;
    margin-top: 20px;
}

.search-bar {
    display: flex;
    align-items: center;
    gap: 10px;
    flex-wrap: wrap;
    margin-bottom: 16px;
}

.search-bar .form-control {
    max-width: 320px;
}

.search-bar select.form-control {
    max-width: 180px;
}

.alert {
    padding: 12px 14px;
    border-radius: 14px;
    margin-bottom: 14px;
    border: 1px solid var(--line);
    background: #fff;
    font-size: 14px;
    font-weight: 700;
}

.alert-error { color: var(--danger); background: var(--danger-soft); border-color: #fecaca; }
.alert-success { color: var(--success); background: var(--success-soft); border-color: #bbf7d0; }
.alert-warning { color: var(--warning); background: var(--warning-soft); border-color: #fde68a; }
.alert-info { color: var(--primary); background: var(--primary-soft); border-color: #bfdbfe; }

.role-badge,
.badge {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    min-height: 24px;
    padding: 3px 9px;
    border-radius: 999px;
    font-size: 12px;
    font-weight: 800;
    white-space: nowrap;
}

.role-badge.admin { background: var(--warning-soft); color: #92400e; }
.role-badge.teacher { background: var(--primary-soft); color: #1e40af; }
.role-badge.student { background: var(--success-soft); color: #166534; }
.badge-approved,
.badge-active { background: var(--success-soft); color: var(--success); }
.badge-pending { background: var(--warning-soft); color: var(--warning); }
.badge-rejected,
.badge-disabled { background: var(--danger-soft); color: var(--danger); }

.qa-result {
    margin-top: 12px;
    padding: 18px;
    border-radius: var(--radius);
    background: #f8fbff;
    border: 1px solid var(--line-soft);
    white-space: pre-wrap;
}

.source-label {
    margin-top: 12px;
    color: var(--muted);
    font-size: 13px;
}

.citation-list {
    display: grid;
    gap: 10px;
    margin-top: 14px;
}

.citation-item {
    padding: 12px 14px;
    border: 1px solid var(--line-soft);
    border-radius: var(--radius-sm);
    background: #fff;
}

.citation-item strong,
.citation-item span {
    display: block;
}

.citation-item span {
    margin-top: 4px;
    color: var(--muted);
    font-size: 12px;
}

.citation-item p {
    margin-top: 8px;
    color: var(--text);
    font-size: 13px;
    line-height: 1.7;
}

.badge-indexed { background: var(--success-soft); color: var(--success); }
.badge-not_indexed { background: var(--surface-tint); color: var(--muted); }
.badge-failed { background: var(--danger-soft); color: var(--danger); }
.text-danger { color: var(--danger); }

.sr-only {
    position: absolute;
    width: 1px;
    height: 1px;
    padding: 0;
    margin: -1px;
    overflow: hidden;
    clip: rect(0, 0, 0, 0);
    border: 0;
}

.empty-state {
    padding: 56px 20px;
    color: var(--muted);
    text-align: center;
}

.state-card {
    text-align: center;
    padding: 64px 24px;
}

.state-card h1 {
    color: var(--primary);
    font-size: 64px;
    line-height: 1;
}

.state-title {
    margin-top: 16px;
    margin-bottom: 8px;
    font-size: 18px;
    font-weight: 800;
}

.back-row {
    margin-bottom: 16px;
}

.meta-line {
    margin-bottom: 16px;
    color: var(--muted);
    font-size: 13px;
}

.content-block {
    white-space: pre-wrap;
    line-height: 1.85;
}

.detail-block {
    margin-bottom: 16px;
}

.question-panel {
    margin-top: 8px;
    padding: 14px;
    border-radius: var(--radius);
    background: var(--surface-tint);
    border: 1px solid var(--line-soft);
}

.answer-card {
    margin-top: 16px;
}

.pagination {
    display: flex;
    justify-content: center;
    gap: 6px;
    margin-top: 18px;
}

.pagination a,
.pagination span {
    padding: 7px 12px;
    border: 1px solid var(--line);
    border-radius: 999px;
    background: #fff;
    color: var(--text);
    font-size: 13px;
}

.pagination .current {
    background: var(--primary);
    color: #fff;
    border-color: var(--primary);
}

.login-wrapper {
    min-height: 100vh;
    padding: 32px;
    display: grid;
    grid-template-columns: minmax(0, 1.15fr) minmax(360px, 0.85fr);
    gap: 24px;
    background:
        radial-gradient(circle at 15% 20%, rgba(37, 99, 235, 0.18), transparent 30%),
        radial-gradient(circle at 70% 85%, rgba(15, 118, 110, 0.14), transparent 32%),
        var(--bg);
}

.login-hero,
.login-card {
    border: 1px solid var(--line-soft);
    border-radius: 28px;
    box-shadow: var(--shadow);
}

.login-hero {
    padding: 56px;
    background:
        linear-gradient(135deg, rgba(16, 32, 51, 0.94), rgba(23, 43, 66, 0.94)),
        var(--sidebar);
    color: #fff;
    display: flex;
    flex-direction: column;
    justify-content: center;
}

.login-hero .brand {
    margin-bottom: 42px;
}

.login-hero h1 {
    max-width: 720px;
    font-size: 46px;
    line-height: 1.12;
    font-weight: 850;
}

.login-hero p {
    max-width: 620px;
    margin-top: 18px;
    color: #c7d5e6;
    font-size: 17px;
}

.login-metrics {
    display: flex;
    gap: 12px;
    flex-wrap: wrap;
    margin-top: 34px;
}

.login-metrics span {
    padding: 12px 14px;
    border: 1px solid rgba(255, 255, 255, 0.12);
    border-radius: 16px;
    background: rgba(255, 255, 255, 0.08);
    color: #c7d5e6;
}

.login-metrics strong {
    color: #fff;
}

.login-card {
    padding: 42px;
    background: rgba(255, 255, 255, 0.96);
    display: flex;
    flex-direction: column;
    justify-content: center;
}

.login-card h1 {
    font-size: 30px;
    font-weight: 850;
}

.login-card .subtitle {
    margin: 6px 0 28px;
    color: var(--muted);
}

.login-hint {
    margin-top: 22px;
    display: flex;
    align-items: center;
    gap: 8px;
    flex-wrap: wrap;
    color: var(--muted);
    font-size: 13px;
}

.login-hint strong {
    padding: 6px 10px;
    border-radius: 999px;
    background: var(--surface-soft);
    color: var(--text);
}

@media (max-width: 980px) {
    .app-shell {
        grid-template-columns: 1fr;
    }

    .sidebar {
        position: static;
        height: auto;
        padding: 16px;
        gap: 16px;
    }

    .side-nav {
        flex-direction: row;
        overflow-x: auto;
        padding-bottom: 2px;
    }

    .side-nav a {
        white-space: nowrap;
    }

    .login-wrapper {
        grid-template-columns: 1fr;
    }
}

@media (max-width: 760px) {
    .container {
        padding: 20px 14px;
    }

    .topbar {
        padding: 14px;
        align-items: flex-start;
        flex-direction: column;
    }

    .page-header[style] {
        align-items: flex-start !important;
        flex-direction: column;
    }

    .dashboard-grid,
    .action-grid,
    .form-row,
    .stats-grid {
        grid-template-columns: 1fr;
    }

    .login-wrapper {
        padding: 14px;
    }

    .login-hero {
        padding: 34px 24px;
    }

    .login-hero h1 {
        font-size: 32px;
    }

    .login-card {
        padding: 28px 22px;
    }

    .search-bar .form-control,
    .search-bar select.form-control,
    .btn {
        width: 100%;
        max-width: none;
    }

    .form-actions,
    .btn-group {
        flex-direction: column;
    }
}

@media (prefers-reduced-motion: reduce) {
    *,
    *::before,
    *::after {
        transition-duration: 0.001ms !important;
        scroll-behavior: auto !important;
    }
}