:root {
    --bg: #0f1419;
    --surface: #171d25;
    --surface-2: #1f2733;
    --border: #2a3441;
    --text: #e7edf4;
    --muted: #93a1b3;
    --primary: #4f8cff;
    --primary-dark: #3a73df;
    --success: #3ecf8e;
    --warning: #ffb020;
    --danger: #ff6b6b;
    --radius: 14px;
    --shadow: 0 12px 30px rgba(0, 0, 0, 0.25);
}

* {
    box-sizing: border-box;
}

body {
    margin: 0;
    font-family: "Segoe UI", system-ui, sans-serif;
    background: linear-gradient(180deg, #0b1016 0%, #121821 100%);
    color: var(--text);
    min-height: 100vh;
}

a {
    color: inherit;
    text-decoration: none;
}

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

.sidebar {
    background: rgba(15, 20, 25, 0.95);
    border-right: 1px solid var(--border);
    padding: 24px 18px;
}

.brand {
    display: flex;
    align-items: center;
    gap: 12px;
    margin-bottom: 28px;
}

.brand-mark {
    width: 42px;
    height: 42px;
    border-radius: 12px;
    display: grid;
    place-items: center;
    background: linear-gradient(135deg, var(--primary), #7c5cff);
    font-weight: 700;
}

.brand small,
.eyebrow,
.muted,
.stat-meta,
.hint {
    color: var(--muted);
}

.sidebar-nav {
    display: grid;
    gap: 8px;
}

.nav-link {
    display: flex;
    align-items: center;
    gap: 10px;
    padding: 12px 14px;
    border-radius: 10px;
    color: var(--muted);
    transition: 0.2s ease;
}

.nav-link:hover,
.nav-link.active {
    background: var(--surface-2);
    color: var(--text);
}

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

.topbar {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 28px 32px 0;
    gap: 16px;
}

.topbar h1 {
    margin: 6px 0 0;
    font-size: 1.8rem;
}

.topbar-actions {
    display: flex;
    align-items: center;
    gap: 12px;
}

.user-chip {
    padding: 8px 12px;
    border-radius: 999px;
    background: var(--surface-2);
    border: 1px solid var(--border);
}

.content {
    padding: 24px 32px 32px;
}

.footer {
    padding: 16px 32px 24px;
    color: var(--muted);
    font-size: 0.9rem;
}

.stats-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(180px, 1fr));
    gap: 16px;
    margin-bottom: 24px;
}

.stat-card {
    background: var(--surface);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    padding: 18px;
    box-shadow: var(--shadow);
}

.stat-card.highlight {
    background: linear-gradient(135deg, rgba(79, 140, 255, 0.18), rgba(124, 92, 255, 0.12));
    border-color: rgba(79, 140, 255, 0.35);
}

.stat-label {
    display: block;
    color: var(--muted);
    font-size: 0.9rem;
}

.stat-value {
    display: block;
    font-size: 2rem;
    margin: 8px 0 4px;
}

.panel-grid {
    display: grid;
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: 20px;
    margin-bottom: 24px;
}

.panel {
    background: var(--surface);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    padding: 20px;
    box-shadow: var(--shadow);
}

.panel-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 16px;
}

.panel-header h2 {
    margin: 0;
    font-size: 1.1rem;
}

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

.question-card {
    background: var(--surface-2);
    border: 1px solid var(--border);
    border-radius: 12px;
    padding: 18px;
}

.question-card h3 {
    margin-top: 0;
}

.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 8px;
    padding: 10px 16px;
    border-radius: 10px;
    border: 1px solid transparent;
    cursor: pointer;
    font-weight: 600;
}

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

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

.btn-secondary {
    background: var(--surface);
    border-color: var(--border);
}

.btn-ghost {
    background: transparent;
    border-color: var(--border);
    color: var(--text);
}

.btn-block {
    width: 100%;
}

.link {
    color: var(--primary);
    font-size: 0.92rem;
}

.alert {
    padding: 12px 14px;
    border-radius: 10px;
    margin-bottom: 16px;
}

.alert-error {
    background: rgba(255, 107, 107, 0.12);
    border: 1px solid rgba(255, 107, 107, 0.35);
    color: #ffc9c9;
}

.auth-page {
    display: grid;
    place-items: center;
    padding: 24px;
}

.auth-card {
    width: min(100%, 420px);
    background: var(--surface);
    border: 1px solid var(--border);
    border-radius: 18px;
    padding: 28px;
    box-shadow: var(--shadow);
}

.auth-brand {
    margin-bottom: 18px;
}

.stack-form {
    display: grid;
    gap: 14px;
    margin-top: 20px;
}

.stack-form label {
    display: grid;
    gap: 8px;
    color: var(--muted);
}

input,
select,
textarea {
    width: 100%;
    padding: 12px 14px;
    border-radius: 10px;
    border: 1px solid var(--border);
    background: var(--surface-2);
    color: var(--text);
}

.coming-soon,
.empty-state {
    padding: 40px;
    text-align: center;
    color: var(--muted);
}

.alert-success {
    background: rgba(62, 207, 142, 0.12);
    border: 1px solid rgba(62, 207, 142, 0.35);
    color: #b8f5d8;
}

.breadcrumb {
    display: flex;
    flex-wrap: wrap;
    align-items: center;
    gap: 8px;
    margin-bottom: 16px;
    color: var(--muted);
    font-size: 0.92rem;
}

.breadcrumb a {
    color: var(--primary);
}

.inline-form {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(160px, 1fr));
    gap: 14px;
    align-items: end;
}

.inline-form label,
.stack-form label {
    display: grid;
    gap: 8px;
    color: var(--muted);
    font-size: 0.92rem;
}

.form-actions {
    display: flex;
    gap: 10px;
    flex-wrap: wrap;
}

.panel-narrow {
    max-width: 520px;
}

.table-wrap {
    overflow-x: auto;
}

.data-table {
    width: 100%;
    border-collapse: collapse;
}

.data-table th,
.data-table td {
    padding: 12px 14px;
    border-bottom: 1px solid var(--border);
    text-align: left;
}

.data-table th {
    color: var(--muted);
    font-size: 0.85rem;
    font-weight: 600;
}

.data-table tbody tr:hover {
    background: rgba(255, 255, 255, 0.02);
}

.actions {
    display: flex;
    flex-wrap: wrap;
    gap: 8px;
    align-items: center;
}

.inline-action {
    display: inline;
    margin: 0;
}

.btn-sm {
    padding: 7px 12px;
    font-size: 0.85rem;
}

.btn-danger {
    background: rgba(255, 107, 107, 0.15);
    border-color: rgba(255, 107, 107, 0.35);
    color: #ffc9c9;
}

.btn-danger:hover {
    background: rgba(255, 107, 107, 0.25);
}

.link-strong {
    color: var(--text);
    font-weight: 600;
}

.link-strong:hover {
    color: var(--primary);
}

.badge {
    display: inline-block;
    padding: 4px 10px;
    border-radius: 999px;
    background: rgba(79, 140, 255, 0.15);
    border: 1px solid rgba(79, 140, 255, 0.3);
    font-size: 0.85rem;
}

.progress-summary {
    display: grid;
    gap: 14px;
}

.progress-bar {
    height: 12px;
    background: var(--surface-2);
    border-radius: 999px;
    overflow: hidden;
    border: 1px solid var(--border);
}

.progress-fill {
    height: 100%;
    background: linear-gradient(90deg, var(--primary), #7c5cff);
    border-radius: 999px;
    transition: width 0.3s ease;
}

.progress-stats {
    display: flex;
    flex-wrap: wrap;
    gap: 18px;
    color: var(--muted);
    font-size: 0.92rem;
}

.progress-stats strong {
    color: var(--text);
}

.topic-assessment-list {
    display: grid;
    gap: 16px;
}

.topic-card {
    background: var(--surface-2);
    border: 1px solid var(--border);
    border-radius: 12px;
    padding: 18px;
}

.topic-card.topic-done {
    border-color: rgba(62, 207, 142, 0.35);
}

.topic-card.topic-weak {
    border-color: rgba(255, 107, 107, 0.35);
}

.topic-card-header {
    display: flex;
    justify-content: space-between;
    align-items: flex-start;
    gap: 12px;
    margin-bottom: 14px;
}

.topic-card-header h3 {
    margin: 0;
    font-size: 1.05rem;
}

.completed-check {
    display: inline-flex;
    align-items: center;
    gap: 10px;
    margin-bottom: 14px;
    cursor: pointer;
    color: var(--text);
}

.completed-check input {
    width: auto;
    accent-color: var(--success);
}

.confidence-block {
    display: grid;
    gap: 10px;
}

.confidence-label {
    color: var(--muted);
    font-size: 0.9rem;
}

.confidence-scale {
    display: flex;
    flex-wrap: wrap;
    gap: 8px;
}

.confidence-btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    min-width: 36px;
    height: 36px;
    padding: 0 10px;
    border-radius: 8px;
    border: 1px solid var(--border);
    background: var(--surface);
    color: var(--muted);
    cursor: pointer;
    font-weight: 600;
    font-size: 0.9rem;
    transition: 0.15s ease;
}

.confidence-btn input {
    display: none;
}

.confidence-btn:hover {
    border-color: var(--primary);
    color: var(--text);
}

.confidence-btn.selected {
    background: var(--primary);
    border-color: var(--primary);
    color: white;
}

.confidence-hint {
    font-size: 0.85rem;
}

.weak-tag {
    margin: 12px 0 0;
    color: var(--danger);
    font-size: 0.88rem;
}

.hidden-form {
    display: none;
}

.small {
    display: block;
    font-size: 0.82rem;
    margin-top: 4px;
}

@media (max-width: 960px) {
    .app-shell {
        grid-template-columns: 1fr;
    }

    .sidebar {
        border-right: none;
        border-bottom: 1px solid var(--border);
    }

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