:root {
    color-scheme: light;
    --bg: #f4f7fb;
    --surface: #ffffff;
    --surface-alt: #f8fafc;
    --text: #111827;
    --muted: #64748b;
    --border: #d8e0ea;
    --primary: #0f766e;
    --primary-hover: #0b5f59;
    --primary-soft: #e6f4f1;
    --success: #15803d;
    --success-soft: #e8f6ee;
    --info: #2563eb;
    --info-soft: #eaf1ff;
    --warning: #b7791f;
    --warning-soft: #fff6db;
    --danger: #b91c1c;
    --danger-soft: #fdecec;
    --locked: #94a3b8;
    --shadow: 0 16px 36px rgba(15, 23, 42, 0.08);
    --radius: 14px;
}

* {
    box-sizing: border-box;
}

html {
    min-width: 0;
}

body {
    margin: 0;
    min-height: 100vh;
    overflow-x: hidden;
    color: var(--text);
    background: var(--bg);
    font-family: Arial, Helvetica, sans-serif;
    line-height: 1.5;
}

button,
input,
select {
    font: inherit;
}

button {
    cursor: pointer;
}

button:disabled,
input:disabled,
select:disabled {
    cursor: not-allowed;
    opacity: 0.68;
}

h1,
h2,
h3,
p {
    margin-top: 0;
}

h1 {
    margin-bottom: 8px;
    font-size: 30px;
    line-height: 1.2;
    letter-spacing: 0;
}

h2 {
    margin-bottom: 16px;
    font-size: 20px;
    line-height: 1.25;
    letter-spacing: 0;
}

h3 {
    margin-bottom: 10px;
    font-size: 17px;
    line-height: 1.35;
    letter-spacing: 0;
}

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

.hidden {
    display: none !important;
}

.container {
    max-width: 1120px;
    margin: 0 auto;
    padding: 32px 24px;
}

.quiz-container {
    max-width: 900px;
}

.lesson-container {
    max-width: 1120px;
}

.topbar {
    position: sticky;
    top: 0;
    z-index: 20;
    display: grid;
    grid-template-columns: auto minmax(0, 1fr) auto;
    align-items: center;
    gap: 16px;
    min-height: 66px;
    padding: 12px max(24px, calc((100vw - 1120px) / 2 + 24px));
    background: rgba(255, 255, 255, 0.96);
    border-bottom: 1px solid var(--border);
}

.brand-button {
    display: inline-flex;
    align-items: center;
    min-height: 42px;
    padding: 0;
    border: 0;
    color: var(--text);
    background: transparent;
    font-size: 19px;
    font-weight: 800;
    letter-spacing: 0;
}

.brand-button:hover,
.brand-button:focus-visible {
    color: var(--primary);
}

.topbar-subtitle {
    min-width: 0;
    overflow: hidden;
    color: var(--muted);
    text-overflow: ellipsis;
    white-space: nowrap;
}

.auth-body {
    min-height: 100vh;
    background: var(--bg);
}

.auth-topbar {
    display: grid;
    grid-template-columns: auto minmax(0, 1fr);
    align-items: center;
    gap: 16px;
    min-height: 66px;
    padding: 12px max(24px, calc((100vw - 1120px) / 2 + 24px));
    background: rgba(255, 255, 255, 0.96);
    border-bottom: 1px solid var(--border);
}

.auth-brand {
    color: var(--text);
    font-size: 19px;
    font-weight: 800;
}

.auth-page {
    display: flex;
    align-items: center;
    justify-content: center;
    min-height: calc(100vh - 66px);
    padding: 24px;
}

.auth-panel {
    width: min(100%, 440px);
    padding: 28px;
    background: var(--surface);
    border: 1px solid var(--border);
    border-radius: 16px;
    box-shadow: var(--shadow);
}

.auth-panel-header {
    display: grid;
    gap: 8px;
    margin-bottom: 24px;
    padding-bottom: 20px;
    border-bottom: 1px solid var(--border);
}

.auth-panel h1 {
    margin-bottom: 0;
}

.auth-submit {
    width: 100%;
}

.auth-panel .message {
    margin: 16px 0 0;
}

.app-shell,
.admin-shell {
    width: 100%;
}

.screen,
.admin-section {
    width: 100%;
}

.section-header {
    display: flex;
    align-items: flex-start;
    justify-content: space-between;
    gap: 18px;
    margin-bottom: 22px;
}

.section-note {
    margin-bottom: 0;
    color: var(--muted);
}

.eyebrow {
    display: block;
    margin-bottom: 4px;
    color: var(--muted);
    font-size: 13px;
    font-weight: 700;
    text-transform: uppercase;
}

.form,
.filters {
    display: grid;
    gap: 14px;
}

.filters {
    grid-template-columns: repeat(auto-fit, minmax(180px, 1fr));
    align-items: end;
    margin-bottom: 22px;
    padding: 18px;
    background: var(--surface);
    border: 1px solid var(--border);
    border-radius: var(--radius);
}

label {
    display: grid;
    gap: 7px;
    color: var(--muted);
    font-size: 14px;
}

input,
select {
    width: 100%;
    min-height: 42px;
    padding: 9px 12px;
    color: var(--text);
    background: #ffffff;
    border: 1px solid var(--border);
    border-radius: 10px;
}

input:focus,
select:focus {
    border-color: var(--primary);
    outline: 3px solid rgba(15, 118, 110, 0.18);
}

.button,
button.button {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    min-height: 42px;
    padding: 10px 16px;
    color: #ffffff;
    background: var(--primary);
    border: 1px solid var(--primary);
    border-radius: 10px;
    font-weight: 700;
    text-decoration: none;
}

.button:hover,
.button:focus-visible {
    background: var(--primary-hover);
    border-color: var(--primary-hover);
}

.button.secondary {
    color: var(--primary);
    background: var(--primary-soft);
    border-color: #b9ded8;
}

.button.secondary:hover,
.button.secondary:focus-visible {
    color: #ffffff;
    background: var(--primary);
    border-color: var(--primary);
}

.button.ghost {
    color: var(--muted);
    background: transparent;
    border-color: var(--border);
}

.button.ghost:hover,
.button.ghost:focus-visible {
    color: var(--text);
    background: var(--surface-alt);
}

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

.button.danger:hover,
.button.danger:focus-visible {
    background: #991b1b;
    border-color: #991b1b;
}

.button.small {
    min-height: 34px;
    padding: 6px 10px;
    font-size: 13px;
}

.link-button {
    display: inline-flex;
    align-items: center;
    min-height: 32px;
    margin-bottom: 10px;
    padding: 0;
    color: var(--primary);
    background: transparent;
    border: 0;
    font-weight: 700;
}

.link-button:hover,
.link-button:focus-visible {
    color: var(--primary-hover);
    text-decoration: underline;
}

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

.message {
    margin-bottom: 18px;
    padding: 13px 15px;
    border-radius: 12px;
    line-height: 1.45;
}

.error-message {
    color: var(--danger);
    background: var(--danger-soft);
    border: 1px solid #f5b7b7;
}

.success-message {
    color: var(--success);
    background: var(--success-soft);
    border: 1px solid #b9e5c9;
}

.empty-state {
    margin: 0;
    padding: 24px;
    color: var(--muted);
    background: var(--surface);
    border: 1px dashed var(--border);
    border-radius: var(--radius);
}

.course-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
    gap: 18px;
}

.course-card {
    display: grid;
    gap: 14px;
    width: 100%;
    min-height: 188px;
    padding: 22px;
    color: var(--text);
    text-align: left;
    background: var(--surface);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    box-shadow: var(--shadow);
}

.course-card:hover,
.course-card:focus-visible {
    border-color: var(--primary);
    transform: translateY(-1px);
}

.course-title {
    min-height: 54px;
    font-size: 19px;
    font-weight: 800;
    line-height: 1.35;
}

.course-card-meta,
.progress-line {
    color: var(--muted);
}

.course-action {
    align-self: end;
    color: var(--primary);
    font-weight: 800;
}

.course-overview,
.video-card,
.next-action,
.work-panel,
.question-block,
.question-result,
.result-summary {
    background: var(--surface);
    border: 1px solid var(--border);
    border-radius: var(--radius);
}

.course-overview {
    display: grid;
    grid-template-columns: minmax(140px, 190px) 1fr;
    align-items: center;
    gap: 18px;
    margin-bottom: 18px;
    padding: 18px;
}

.course-overview strong {
    font-size: 24px;
}

.progress-bar {
    overflow: hidden;
    width: 100%;
    height: 10px;
    background: #e2e8f0;
    border-radius: 999px;
}

.progress-bar > span {
    display: block;
    width: 0%;
    height: 100%;
    background: var(--primary);
    border-radius: inherit;
    transition: width 180ms ease;
}

.lesson-list {
    display: grid;
    gap: 12px;
}

.lesson-row {
    display: grid;
    grid-template-columns: minmax(0, 1fr) auto;
    align-items: center;
    gap: 16px;
    width: 100%;
    min-height: 76px;
    padding: 16px 18px;
    color: var(--text);
    text-align: left;
    background: var(--surface);
    border: 1px solid var(--border);
    border-radius: var(--radius);
}

.lesson-row:not(:disabled):hover,
.lesson-row:not(:disabled):focus-visible {
    border-color: var(--primary);
    box-shadow: 0 10px 24px rgba(15, 23, 42, 0.06);
}

.lesson-row.locked {
    color: #6b7280;
    background: #f8fafc;
}

.lesson-row:disabled {
    opacity: 1;
}

.lesson-title-group {
    display: grid;
    gap: 7px;
    min-width: 0;
}

.lesson-title {
    overflow-wrap: anywhere;
    font-weight: 800;
}

.lesson-badges {
    display: flex;
    flex-wrap: wrap;
    gap: 8px;
}

.status-pill,
.badge {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    min-height: 28px;
    padding: 4px 10px;
    border-radius: 999px;
    font-size: 13px;
    font-weight: 800;
    white-space: nowrap;
}

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

.status-pill.completed {
    color: var(--success);
    background: var(--success-soft);
}

.status-pill.available {
    color: var(--info);
    background: var(--info-soft);
}

.status-pill.locked {
    color: #64748b;
    background: #eef2f7;
}

.lesson-meta {
    display: flex;
    flex-wrap: wrap;
    gap: 8px;
    margin-bottom: 0;
}

.video-card {
    padding: 16px;
    box-shadow: var(--shadow);
}

.video-wrap {
    overflow: hidden;
    background: #000000;
    border-radius: 12px;
}

.video-player,
video {
    display: block;
    width: 100%;
    max-height: 70vh;
    background: #000000;
}

.next-action {
    display: grid;
    gap: 14px;
    margin-top: 18px;
    padding: 18px;
}

.next-action p {
    margin-bottom: 0;
    color: var(--muted);
}

.test-form {
    display: grid;
    gap: 16px;
}

.question-block {
    margin: 0;
    padding: 18px;
}

.question-block legend {
    padding: 0;
    color: var(--text);
    font-weight: 800;
    line-height: 1.4;
}

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

.answer-option {
    display: flex;
    align-items: flex-start;
    gap: 10px;
    padding: 12px;
    color: var(--text);
    background: var(--surface-alt);
    border: 1px solid var(--border);
    border-radius: 12px;
}

.answer-option:hover {
    border-color: #b9ded8;
}

.answer-option input {
    width: auto;
    min-height: auto;
    margin-top: 4px;
}

.result-block {
    display: grid;
    gap: 12px;
    margin-top: 18px;
}

.result-summary,
.question-result {
    padding: 18px;
}

.result-summary.passed,
.question-result.passed {
    border-color: #b9e5c9;
    background: var(--success-soft);
}

.result-summary.failed,
.question-result.failed {
    border-color: #f5b7b7;
    background: var(--danger-soft);
}

.status-text {
    margin-bottom: 0;
    font-weight: 800;
}

.admin-nav {
    display: flex;
    flex-wrap: wrap;
    gap: 8px;
    margin-bottom: 22px;
}

.nav-button {
    min-height: 42px;
    padding: 9px 14px;
    color: var(--text);
    background: var(--surface);
    border: 1px solid var(--border);
    border-radius: 10px;
    font-weight: 800;
}

.nav-button.active,
.nav-button:hover,
.nav-button:focus-visible {
    color: #ffffff;
    background: var(--primary);
    border-color: var(--primary);
}

.admin-grid {
    display: grid;
    grid-template-columns: minmax(260px, 360px) minmax(0, 1fr);
    gap: 18px;
    align-items: start;
}

.work-panel {
    padding: 18px;
}

.wide-panel {
    min-width: 0;
}

.table-wrap {
    width: 100%;
    overflow-x: auto;
    background: var(--surface);
    border: 1px solid var(--border);
    border-radius: var(--radius);
}

table {
    width: 100%;
    min-width: 780px;
    border-collapse: collapse;
}

th,
td {
    padding: 12px 13px;
    border-bottom: 1px solid var(--border);
    text-align: left;
    vertical-align: top;
    white-space: nowrap;
}

th {
    color: var(--muted);
    background: var(--surface-alt);
    font-size: 13px;
    font-weight: 800;
}

tr:last-child td {
    border-bottom: 0;
}

td {
    color: #1f2937;
}

@media (max-width: 760px) {
    .container {
        padding: 22px 16px 34px;
    }

    .topbar {
        grid-template-columns: 1fr auto;
        gap: 8px 12px;
        padding: 12px 16px;
    }

    .auth-topbar {
        grid-template-columns: 1fr;
        gap: 2px;
        padding: 12px 16px;
    }

    .topbar-subtitle {
        grid-column: 1 / -1;
        order: 3;
        white-space: normal;
    }

    .section-header,
    .lesson-row {
        grid-template-columns: 1fr;
        flex-direction: column;
        align-items: stretch;
    }

    .course-grid,
    .admin-grid,
    .filters,
    .course-overview {
        grid-template-columns: 1fr;
    }

    h1 {
        font-size: 26px;
    }

    .course-title {
        min-height: auto;
    }
}