/* ============================================================
   Preceptor — clinical-calm design system
   Light neutral surface · deep teal-ink primary · restrained clay accent
   Serif display for titles · humanist sans for UI
   ============================================================ */

:root {
    /* Color */
    --surface: #f6f5f1;
    --surface-raised: #ffffff;
    --surface-sunken: #efede7;
    --ink: #1c2a27;
    --ink-muted: #5c6b67;
    --ink-faint: #8a968f;
    --primary: #14514b;
    --primary-strong: #0e3b37;
    --primary-soft: #e2ecea;
    --accent: #b96a45;
    --accent-soft: #f3e6de;
    --success: #3e7b54;
    --success-soft: #e4efe7;
    --danger: #a2453b;
    --danger-soft: #f5e4e1;
    --border: #e2e0d8;
    --border-strong: #cfccc1;

    /* Type */
    --font-serif: "Iowan Old Style", "Palatino Linotype", Palatino, "Book Antiqua", Georgia, serif;
    --font-sans: Seravek, "Gill Sans Nova", Ubuntu, Calibri, "DM Sans", source-sans-pro, system-ui, sans-serif;

    /* Rhythm */
    --space-1: 0.25rem;
    --space-2: 0.5rem;
    --space-3: 0.75rem;
    --space-4: 1rem;
    --space-5: 1.5rem;
    --space-6: 2rem;
    --space-7: 3rem;
    --space-8: 4rem;

    --radius-sm: 6px;
    --radius: 10px;
    --radius-lg: 14px;

    --shadow-card: 0 1px 2px rgb(28 42 39 / 0.05), 0 4px 16px rgb(28 42 39 / 0.05);
    --shadow-raised: 0 2px 6px rgb(28 42 39 / 0.08), 0 12px 32px rgb(28 42 39 / 0.10);

    --transition: 180ms ease;
    --content-width: 72rem;
}

*,
*::before,
*::after {
    box-sizing: border-box;
}

html {
    -webkit-text-size-adjust: 100%;
}

body {
    margin: 0;
    background: var(--surface);
    color: var(--ink);
    font-family: var(--font-sans);
    font-size: 1rem;
    line-height: 1.55;
}

img,
video {
    max-width: 100%;
    display: block;
}

h1,
h2,
h3,
h4 {
    margin: 0;
    line-height: 1.2;
    font-weight: 600;
}

p {
    margin: 0 0 var(--space-4);
}

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

:focus-visible {
    outline: 2px solid var(--primary);
    outline-offset: 2px;
    border-radius: 2px;
}

@media (prefers-reduced-motion: reduce) {

    *,
    *::before,
    *::after {
        animation-duration: 0.01ms !important;
        animation-iteration-count: 1 !important;
        transition-duration: 0.01ms !important;
    }
}

/* ---------- App shell ---------- */

.app-shell {
    min-height: 100dvh;
    display: flex;
    flex-direction: column;
}

.app-header {
    background: var(--surface-raised);
    border-bottom: 1px solid var(--border);
}

.app-header-inner {
    max-width: var(--content-width);
    margin: 0 auto;
    padding: 0 var(--space-5);
    height: 3.75rem;
    display: flex;
    align-items: center;
    gap: var(--space-6);
}

.brand {
    display: inline-flex;
    align-items: center;
    gap: var(--space-2);
    color: var(--primary-strong);
    text-decoration: none;
}

.brand-mark {
    width: 1.4rem;
    height: 1.4rem;
    color: var(--primary);
}

.brand-mark-lg {
    width: 2.2rem;
    height: 2.2rem;
}

.visually-hidden {
    position: absolute;
    width: 1px;
    height: 1px;
    margin: -1px;
    padding: 0;
    overflow: hidden;
    clip-path: inset(50%);
    white-space: nowrap;
    border: 0;
}

.brand-logo {
    height: 1.75rem;
    width: auto;
    max-width: 12rem;
    object-fit: contain;
}

.brand-logo-lg {
    height: 4rem;
    max-width: 18rem;
}

.brand-name {
    font-family: var(--font-serif);
    font-size: 1.3rem;
    font-weight: 600;
    letter-spacing: 0.01em;
}

.app-nav {
    display: flex;
    gap: var(--space-2);
    flex: 1;
}

.app-nav-link {
    padding: var(--space-2) var(--space-3);
    border-radius: var(--radius-sm);
    color: var(--ink-muted);
    text-decoration: none;
    font-weight: 500;
    transition: color var(--transition), background var(--transition);
}

.app-nav-link:hover {
    color: var(--ink);
    background: var(--surface-sunken);
}

.app-nav-link.active {
    color: var(--primary-strong);
    background: var(--primary-soft);
}

.app-user {
    display: flex;
    align-items: center;
    gap: var(--space-3);
    margin-left: auto;
}

.app-user-name {
    color: var(--ink-muted);
    font-size: 0.925rem;
}

.logout-form {
    margin: 0;
}

.app-main {
    flex: 1;
    width: 100%;
    max-width: var(--content-width);
    margin: 0 auto;
    padding: var(--space-6) var(--space-5) var(--space-8);
}

.app-footer {
    border-top: 1px solid var(--border);
    padding: var(--space-4) var(--space-5);
    text-align: center;
    color: var(--ink-faint);
    font-size: 0.85rem;
    display: flex;
    justify-content: center;
    gap: var(--space-3);
    flex-wrap: wrap;
}

.app-footer-link {
    color: var(--primary);
}

/* ---------- Focus shell (login, password) ---------- */

.focus-shell {
    min-height: 100dvh;
    display: grid;
    place-items: center;
    padding: var(--space-5);
    background:
        radial-gradient(80rem 40rem at 110% -20%, var(--primary-soft), transparent 60%),
        var(--surface);
}

.focus-card {
    width: 100%;
    max-width: 26rem;
    background: var(--surface-raised);
    border: 1px solid var(--border);
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-card);
    padding: var(--space-7) var(--space-6);
}

.focus-brand {
    text-align: center;
    margin-bottom: var(--space-6);
}

.focus-brand .brand-mark,
.focus-brand .brand-logo {
    margin: 0 auto var(--space-3);
}

.focus-title {
    font-family: var(--font-serif);
    font-size: 1.75rem;
    color: var(--primary-strong);
}

.focus-subtitle {
    margin: var(--space-2) 0 0;
    color: var(--ink-muted);
}

.focus-footnote {
    margin: var(--space-5) 0 0;
    text-align: center;
    color: var(--ink-faint);
    font-size: 0.85rem;
}

/* ---------- Typography helpers ---------- */

.page-title {
    font-family: var(--font-serif);
    font-size: 2rem;
    color: var(--primary-strong);
    margin-bottom: var(--space-2);
}

.page-lede {
    color: var(--ink-muted);
    max-width: 46rem;
    margin-bottom: var(--space-6);
}

.section-title {
    font-size: 1.1rem;
    font-weight: 600;
    margin-bottom: var(--space-4);
}

/* ---------- Buttons ---------- */

.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: var(--space-2);
    padding: 0.55rem 1.1rem;
    border-radius: var(--radius-sm);
    border: 1px solid transparent;
    font-family: inherit;
    font-size: 0.95rem;
    font-weight: 500;
    line-height: 1.2;
    text-decoration: none;
    cursor: pointer;
    transition: background var(--transition), border-color var(--transition), color var(--transition);
}

.btn:disabled {
    opacity: 0.55;
    cursor: not-allowed;
}

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

.btn-primary:hover:not(:disabled) {
    background: var(--primary-strong);
}

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

.btn-secondary:hover:not(:disabled) {
    border-color: var(--primary);
    color: var(--primary-strong);
}

.btn-ghost {
    background: transparent;
    color: var(--ink-muted);
}

.btn-ghost:hover:not(:disabled) {
    color: var(--ink);
    background: var(--surface-sunken);
}

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

.btn-danger:hover:not(:disabled) {
    background: var(--danger);
    color: #fff;
}

.btn-sm {
    padding: 0.3rem 0.7rem;
    font-size: 0.85rem;
}

.btn-block {
    width: 100%;
}

/* ---------- Forms ---------- */

.field {
    margin-bottom: var(--space-4);
}

.field-label {
    display: block;
    font-size: 0.875rem;
    font-weight: 600;
    margin-bottom: var(--space-1);
}

.field-hint {
    display: block;
    margin-top: var(--space-1);
    font-size: 0.8rem;
    color: var(--ink-faint);
}

.input,
select.input,
textarea.input {
    width: 100%;
    padding: 0.55rem 0.75rem;
    border: 1px solid var(--border-strong);
    border-radius: var(--radius-sm);
    background: var(--surface-raised);
    color: var(--ink);
    font-family: inherit;
    font-size: 0.95rem;
    transition: border-color var(--transition);
}

.input:focus {
    outline: none;
    border-color: var(--primary);
    box-shadow: 0 0 0 3px var(--primary-soft);
}

textarea.input {
    resize: vertical;
    min-height: 6rem;
}

/* ---------- Alerts ---------- */

.alert {
    padding: var(--space-3) var(--space-4);
    border-radius: var(--radius-sm);
    margin-bottom: var(--space-4);
    font-size: 0.925rem;
}

.alert-error {
    background: var(--danger-soft);
    color: var(--danger);
    border: 1px solid color-mix(in srgb, var(--danger) 25%, transparent);
}

.alert-list {
    margin: var(--space-2) 0 0;
    padding-left: 1.25rem;
}

.alert-success {
    background: var(--success-soft);
    color: var(--success);
    border: 1px solid color-mix(in srgb, var(--success) 25%, transparent);
}

.alert-info {
    background: var(--primary-soft);
    color: var(--primary-strong);
    border: 1px solid color-mix(in srgb, var(--primary) 20%, transparent);
}

/* ---------- Cards ---------- */

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

.card-body {
    padding: var(--space-5);
}

/* ---------- Empty states ---------- */

.empty-state {
    max-width: 30rem;
    margin: var(--space-8) auto;
    text-align: center;
}

.empty-state-copy {
    color: var(--ink-muted);
    margin-bottom: var(--space-5);
}

/* ---------- Tables ---------- */

.table-wrap {
    overflow-x: auto;
    background: var(--surface-raised);
    border: 1px solid var(--border);
    border-radius: var(--radius);
}

.table {
    width: 100%;
    border-collapse: collapse;
    font-size: 0.925rem;
}

.table th {
    text-align: left;
    font-weight: 600;
    color: var(--ink-muted);
    font-size: 0.8rem;
    text-transform: uppercase;
    letter-spacing: 0.04em;
    padding: var(--space-3) var(--space-4);
    border-bottom: 1px solid var(--border);
    white-space: nowrap;
}

.table td {
    padding: var(--space-3) var(--space-4);
    border-bottom: 1px solid var(--border);
    vertical-align: middle;
}

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

.table tbody tr:hover {
    background: var(--surface-sunken);
}

/* ---------- Badges ---------- */

.badge {
    display: inline-flex;
    align-items: center;
    padding: 0.15rem 0.6rem;
    border-radius: 999px;
    font-size: 0.75rem;
    font-weight: 600;
    letter-spacing: 0.02em;
}

.badge-published {
    background: var(--success-soft);
    color: var(--success);
}

.badge-draft {
    background: var(--surface-sunken);
    color: var(--ink-muted);
}

.badge-inactive {
    background: var(--danger-soft);
    color: var(--danger);
}

.badge-admin {
    background: var(--accent-soft);
    color: var(--accent);
}

/* ---------- Blazor plumbing ---------- */

#blazor-error-ui {
    display: none;
    position: fixed;
    bottom: 0;
    left: 0;
    right: 0;
    z-index: 1000;
    background: var(--danger);
    color: #fff;
    padding: var(--space-3) var(--space-5);
}

#blazor-error-ui .reload {
    color: #fff;
    margin-left: var(--space-3);
}

#blazor-error-ui .dismiss {
    float: right;
    cursor: pointer;
}

/* ---------- Responsive ---------- */

@media (max-width: 768px) {

    .app-header-inner {
        gap: var(--space-3);
        padding: 0 var(--space-4);
    }

    .app-user-name {
        display: none;
    }

    .app-main {
        padding: var(--space-5) var(--space-4) var(--space-7);
    }

    .page-title {
        font-size: 1.6rem;
    }
}

/* ---------- Page header ---------- */

.page-header {
    display: flex;
    align-items: flex-start;
    justify-content: space-between;
    gap: var(--space-5);
    margin-bottom: var(--space-5);
}

.back-link {
    display: inline-block;
    font-size: 0.85rem;
    color: var(--ink-muted);
    text-decoration: none;
    margin-bottom: var(--space-2);
}

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

/* ---------- Admin shell ---------- */

.admin-shell {
    display: flex;
    flex-direction: column;
    gap: var(--space-5);
}

.admin-nav {
    display: flex;
    gap: var(--space-1);
    border-bottom: 1px solid var(--border);
    padding-bottom: 0;
}

.admin-nav-link {
    padding: var(--space-2) var(--space-4);
    color: var(--ink-muted);
    text-decoration: none;
    font-weight: 500;
    font-size: 0.95rem;
    border-bottom: 2px solid transparent;
    margin-bottom: -1px;
    transition: color var(--transition), border-color var(--transition);
}

.admin-nav-link:hover {
    color: var(--ink);
}

.admin-nav-link.active {
    color: var(--primary-strong);
    border-bottom-color: var(--primary);
}

/* ---------- Admin tables & forms ---------- */

.create-card {
    margin-bottom: var(--space-5);
}

.form-row {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: var(--space-4);
}

.form-actions {
    display: flex;
    justify-content: flex-end;
    gap: var(--space-3);
    margin-top: var(--space-4);
}

.form-actions-spacer {
    flex: 1;
}

.cell-muted {
    color: var(--ink-muted);
}

.cell-actions {
    text-align: right;
    white-space: nowrap;
}

.cell-sort {
    width: 4.5rem;
}

.cell-filename {
    font-weight: 500;
    word-break: break-all;
}

.user-name {
    font-weight: 500;
    margin-right: var(--space-2);
}

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

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

.slug-hint {
    display: block;
    font-size: 0.8rem;
    margin-top: 2px;
}

.sort-buttons {
    display: inline-flex;
    gap: 2px;
}

.icon-btn {
    border: 1px solid var(--border);
    background: var(--surface-raised);
    color: var(--ink-muted);
    border-radius: var(--radius-sm);
    width: 1.7rem;
    height: 1.7rem;
    cursor: pointer;
    line-height: 1;
    transition: color var(--transition), border-color var(--transition);
}

.icon-btn:hover:not(:disabled) {
    color: var(--primary-strong);
    border-color: var(--primary);
}

.icon-btn:disabled {
    opacity: 0.35;
    cursor: default;
}

.input-inline {
    width: auto;
    min-width: 16rem;
}

.loading {
    color: var(--ink-muted);
}

/* ---------- Temp password notice ---------- */

.temp-password-notice {
    line-height: 1.7;
}

.temp-password {
    display: inline-block;
    background: var(--surface-raised);
    border: 1px dashed var(--primary);
    border-radius: var(--radius-sm);
    padding: 0.1rem 0.6rem;
    font-size: 1rem;
    letter-spacing: 0.05em;
    margin: 0 var(--space-2);
    user-select: all;
}

.temp-password-hint {
    display: block;
    font-size: 0.85rem;
    color: var(--ink-muted);
}

/* ---------- Enrollment editor ---------- */

.enrollment-row td {
    background: var(--surface-sunken);
}

.enrollment-editor {
    padding: var(--space-2) 0;
}

.enrollment-title {
    display: block;
    font-weight: 600;
    font-size: 0.875rem;
    margin-bottom: var(--space-3);
}

.enrollment-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(16rem, 1fr));
    gap: var(--space-2) var(--space-5);
}

.enrollment-option {
    display: flex;
    align-items: center;
    gap: var(--space-2);
    cursor: pointer;
}

/* ---------- Course editor ---------- */

.editor-grid {
    display: grid;
    grid-template-columns: 1.6fr 1fr;
    gap: var(--space-5);
    margin-bottom: var(--space-5);
}

.cover-preview {
    border-radius: var(--radius-sm);
    border: 1px solid var(--border);
    margin-bottom: var(--space-3);
    aspect-ratio: 16 / 9;
    object-fit: cover;
    width: 100%;
}

.cover-placeholder {
    aspect-ratio: 16 / 9;
    display: grid;
    place-items: center;
    background: var(--surface-sunken);
    border: 1px dashed var(--border-strong);
    border-radius: var(--radius-sm);
    color: var(--ink-faint);
    margin-bottom: var(--space-3);
}

.section-header {
    display: flex;
    align-items: baseline;
    justify-content: space-between;
    gap: var(--space-4);
    margin-bottom: var(--space-4);
}

.section-header .section-title {
    margin-bottom: 0;
}

.chapter-list {
    list-style: none;
    margin: 0 0 var(--space-4);
    padding: 0;
    display: flex;
    flex-direction: column;
    gap: var(--space-2);
}

.chapter-item {
    border: 1px solid var(--border);
    border-radius: var(--radius-sm);
    background: var(--surface-raised);
    transition: border-color var(--transition), box-shadow var(--transition);
}

.chapter-item.dragging {
    opacity: 0.5;
}

.chapter-item.drag-over {
    border-color: var(--primary);
    box-shadow: 0 0 0 2px var(--primary-soft);
}

.chapter-row {
    display: flex;
    align-items: center;
    gap: var(--space-3);
    padding: var(--space-3) var(--space-4);
}

.chapter-grip {
    color: var(--ink-faint);
    cursor: grab;
    font-size: 1rem;
}

.chapter-number {
    color: var(--ink-faint);
    font-size: 0.85rem;
    min-width: 1.2rem;
    text-align: right;
}

.chapter-main {
    flex: 1;
    display: flex;
    flex-direction: column;
    gap: 2px;
    min-width: 0;
}

.chapter-title {
    font-weight: 500;
}

.chapter-meta {
    display: flex;
    gap: var(--space-4);
    font-size: 0.8rem;
    color: var(--ink-muted);
}

.chapter-meta-warn {
    color: var(--accent);
}

.chapter-editor {
    border-top: 1px solid var(--border);
    padding: var(--space-4);
    background: var(--surface-sunken);
    border-radius: 0 0 var(--radius-sm) var(--radius-sm);
}

.chapter-editor-actions {
    align-items: center;
}

.add-chapter {
    display: flex;
    gap: var(--space-3);
}

.add-chapter-input {
    max-width: 24rem;
}

/* ---------- Upload widget ---------- */

.video-upload {
    display: flex;
    flex-direction: column;
    gap: var(--space-2);
    align-items: flex-start;
}

.upload-trigger {
    cursor: pointer;
}

.upload-progress {
    display: flex;
    align-items: center;
    gap: var(--space-3);
    width: 100%;
}

.upload-progress-track {
    flex: 1;
    height: 6px;
    border-radius: 999px;
    background: var(--surface-sunken);
    overflow: hidden;
}

.upload-progress-fill {
    height: 100%;
    background: var(--primary);
    border-radius: 999px;
    transition: width 300ms linear;
}

.upload-progress-label {
    font-size: 0.8rem;
    color: var(--ink-muted);
    white-space: nowrap;
}

.upload-error {
    color: var(--danger);
    font-size: 0.85rem;
}

/* ---------- Modal ---------- */

.modal-backdrop {
    position: fixed;
    inset: 0;
    background: rgb(28 42 39 / 0.4);
    display: grid;
    place-items: center;
    z-index: 100;
    padding: var(--space-5);
}

.modal-card {
    background: var(--surface-raised);
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-raised);
    max-width: 26rem;
    width: 100%;
    padding: var(--space-6);
}

.modal-title {
    font-family: var(--font-serif);
    font-size: 1.3rem;
    color: var(--primary-strong);
    margin-bottom: var(--space-3);
}

.modal-copy {
    color: var(--ink-muted);
}

.modal-actions {
    display: flex;
    justify-content: flex-end;
    gap: var(--space-3);
    margin-top: var(--space-5);
}

@media (max-width: 768px) {

    .editor-grid,
    .form-row {
        grid-template-columns: 1fr;
    }

    .page-header {
        flex-direction: column;
    }
}

/* ---------- Dashboard course cards ---------- */

.course-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(19rem, 1fr));
    gap: var(--space-5);
    margin-top: var(--space-5);
}

.course-card {
    background: var(--surface-raised);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    box-shadow: var(--shadow-card);
    overflow: hidden;
    transition: box-shadow var(--transition), transform var(--transition);
}

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

.course-card-link {
    display: block;
    color: inherit;
    text-decoration: none;
    height: 100%;
}

.course-card-cover {
    width: 100%;
    aspect-ratio: 16 / 9;
    object-fit: cover;
    border-bottom: 1px solid var(--border);
}

.course-card-cover-empty {
    display: grid;
    place-items: center;
    background:
        radial-gradient(24rem 12rem at 80% -20%, var(--primary-soft), transparent 70%),
        var(--surface-sunken);
    color: var(--primary);
    font-family: var(--font-serif);
    font-size: 2.5rem;
    letter-spacing: 0.05em;
}

.course-card-body {
    padding: var(--space-4) var(--space-5) var(--space-5);
}

.course-card-heading {
    display: flex;
    align-items: flex-start;
    justify-content: space-between;
    gap: var(--space-3);
    margin-bottom: var(--space-2);
}

.course-card-title {
    font-family: var(--font-serif);
    font-size: 1.25rem;
    color: var(--primary-strong);
}

.course-card-description {
    color: var(--ink-muted);
    font-size: 0.925rem;
    display: -webkit-box;
    -webkit-line-clamp: 3;
    -webkit-box-orient: vertical;
    overflow: hidden;
}

.course-card-footer {
    display: flex;
    align-items: center;
    justify-content: space-between;
    margin-top: var(--space-4);
}

.course-card-progress-label {
    font-size: 0.8rem;
    color: var(--ink-faint);
}

/* ---------- Progress ring ---------- */

.progress-ring {
    width: 2.75rem;
    height: 2.75rem;
    flex-shrink: 0;
}

.progress-ring-track {
    fill: none;
    stroke: var(--surface-sunken);
    stroke-width: 3;
}

.progress-ring-fill {
    fill: none;
    stroke: var(--primary);
    stroke-width: 3;
    stroke-linecap: round;
    transition: stroke-dasharray 400ms ease;
}

.progress-ring-complete {
    stroke: var(--success);
}

.progress-ring-check {
    fill: none;
    stroke: var(--success);
    stroke-width: 2.4;
    stroke-linecap: round;
    stroke-linejoin: round;
}

.progress-ring-text {
    font-size: 9px;
    font-weight: 600;
    fill: var(--ink-muted);
}

/* ---------- Course page layout ---------- */

.course-layout {
    display: grid;
    grid-template-columns: 19rem 1fr;
    gap: var(--space-6);
    align-items: start;
}

.chapter-nav {
    position: sticky;
    top: var(--space-5);
}

.chapter-nav-title {
    font-family: var(--font-serif);
    font-size: 1.4rem;
    color: var(--primary-strong);
    margin: var(--space-2) 0 var(--space-1);
}

.chapter-nav-progress {
    font-size: 0.85rem;
    color: var(--ink-faint);
    margin-bottom: var(--space-4);
}

.chapter-nav-list {
    list-style: none;
    margin: 0;
    padding: 0;
    display: flex;
    flex-direction: column;
    gap: var(--space-1);
}

.chapter-nav-item {
    display: flex;
    align-items: center;
    gap: var(--space-3);
    width: 100%;
    text-align: left;
    background: transparent;
    border: 1px solid transparent;
    border-radius: var(--radius-sm);
    padding: var(--space-2) var(--space-3);
    cursor: pointer;
    font-family: inherit;
    font-size: 0.925rem;
    color: var(--ink);
    transition: background var(--transition), border-color var(--transition);
}

.chapter-nav-item:hover {
    background: var(--surface-sunken);
}

.chapter-nav-item.current {
    background: var(--primary-soft);
    border-color: color-mix(in srgb, var(--primary) 25%, transparent);
    color: var(--primary-strong);
}

.chapter-nav-status {
    width: 1.5rem;
    height: 1.5rem;
    border-radius: 50%;
    display: grid;
    place-items: center;
    flex-shrink: 0;
    background: var(--surface-sunken);
    color: var(--ink-muted);
    font-size: 0.75rem;
}

.chapter-nav-item.current .chapter-nav-status {
    background: var(--surface-raised);
}

.check-icon {
    width: 0.9rem;
    height: 0.9rem;
    color: var(--success);
}

.chapter-nav-label {
    display: flex;
    flex-direction: column;
    min-width: 0;
}

.chapter-nav-name {
    overflow-wrap: anywhere;
}

.chapter-nav-duration {
    font-size: 0.75rem;
    color: var(--ink-faint);
}

/* ---------- Player ---------- */

.player-frame {
    background: #0c1514;
    border-radius: var(--radius);
    overflow: hidden;
    box-shadow: var(--shadow-card);
}

.player-video {
    width: 100%;
    aspect-ratio: 16 / 9;
    display: block;
    background: #0c1514;
}

.player-placeholder {
    aspect-ratio: 16 / 9;
    display: grid;
    place-items: center;
    color: var(--surface);
    opacity: 0.8;
}

.chapter-detail {
    padding: var(--space-5) var(--space-2);
}

.chapter-detail-title {
    font-family: var(--font-serif);
    font-size: 1.5rem;
    color: var(--primary-strong);
    margin-bottom: var(--space-3);
}

.chapter-summary {
    color: var(--ink);
    max-width: 46rem;
}

.chapter-summary ul {
    margin: 0 0 var(--space-4);
    padding-left: 1.4rem;
}

/* ---------- Drive document block ---------- */

.drive-block {
    margin-top: var(--space-6);
    background: var(--surface-raised);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    padding: var(--space-4) var(--space-5) var(--space-5);
}

.drive-block-header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: var(--space-4);
    margin-bottom: var(--space-4);
}

.drive-block-title {
    font-size: 1rem;
    font-weight: 600;
}

.drive-frame {
    width: 100%;
    height: 32rem;
    border: 1px solid var(--border);
    border-radius: var(--radius-sm);
    background: var(--surface-sunken);
}

.drive-help {
    margin-top: var(--space-3);
    font-size: 0.85rem;
    color: var(--ink-muted);
}

.drive-help summary {
    cursor: pointer;
    color: var(--ink-faint);
}

.drive-help p {
    margin-top: var(--space-2);
}

/* ---------- Progress matrix ---------- */

.course-picker {
    margin-bottom: var(--space-5);
}

.matrix-table .matrix-chapter {
    text-align: center;
    min-width: 2.5rem;
}

.matrix-cell {
    text-align: center;
}

.matrix-done {
    color: var(--success);
    font-weight: 700;
}

.matrix-partial {
    color: var(--ink-muted);
    font-size: 0.8rem;
}

.matrix-none {
    color: var(--border-strong);
}

.link-button {
    background: none;
    border: none;
    padding: 0;
    font: inherit;
    font-weight: 500;
    color: var(--primary-strong);
    cursor: pointer;
    text-decoration: underline;
    text-decoration-color: transparent;
    transition: text-decoration-color var(--transition);
}

.link-button:hover {
    text-decoration-color: currentColor;
}

.drilldown-list {
    list-style: none;
    margin: var(--space-2) 0 0;
    padding: 0;
    display: flex;
    flex-direction: column;
    gap: var(--space-2);
}

.drilldown-item {
    display: flex;
    align-items: center;
    gap: var(--space-4);
}

.drilldown-chapter {
    flex: 1;
    font-weight: 500;
}

/* ---------- Course page responsive ---------- */

@media (max-width: 900px) {

    .course-layout {
        grid-template-columns: 1fr;
    }

    .chapter-nav {
        position: static;
        order: 2;
    }

    .chapter-content {
        order: 1;
    }
}

/* ---------- Branding admin ---------- */

.color-field {
    display: flex;
    align-items: center;
    gap: var(--space-2);
}

.color-swatch {
    width: 2.75rem;
    height: 2.5rem;
    padding: 0;
    border: 1px solid var(--border-strong);
    border-radius: var(--radius-sm);
    background: var(--surface-raised);
    cursor: pointer;
}

.brand-logo-preview {
    display: flex;
    align-items: center;
    justify-content: center;
    padding: var(--space-5);
    margin-bottom: var(--space-4);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    background: var(--surface-sunken);
}