/* ==========================================================================
   HỌC VIỆN PHÒNG CHÁY CHỮA CHÁY VÀ CỨU NẠN, CỨU HỘ
   KHOA CƠ SỞ NGÀNH PCCC (K6)
   Học phần: Nhiệt động kỹ thuật và truyền nhiệt trong PCCC (Mã 6.01)
   Stylesheet: app.css (Mobile-First, Clean Flat Academic Design)
   ========================================================================== */

:root {
    --primary: #0b2545;
    --primary-light: #164070;
    --primary-dark: #07172b;
    --accent: #b71c1c;
    --accent-hover: #d32f2f;
    --gold: #d48806;
    --gold-light: #fffbe6;
    --text-main: #1e293b;
    --text-muted: #64748b;
    --text-light: #94a3b8;
    --bg-page: #f8fafc;
    --bg-white: #ffffff;
    --border: #e2e8f0;
    --border-light: #f1f5f9;
    --radius-sm: 4px;
    --radius-md: 8px;
    --radius-lg: 12px;
}

/* 1. Global Reset & Viewport Constraints (Prevents any horizontal overflow) */
html, body {
    margin: 0;
    padding: 0;
    width: 100%;
    max-width: 100vw;
    overflow-x: hidden;
    background-color: var(--bg-page);
    color: var(--text-main);
    font-family: 'Be Vietnam Pro', -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
    font-size: 15px;
    line-height: 1.7;
    -webkit-text-size-adjust: 100%;
    -webkit-font-smoothing: antialiased;
}

*, *::before, *::after {
    box-sizing: border-box;
    max-width: 100%;
}

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

a {
    color: var(--primary);
    text-decoration: none;
    transition: color 0.15s ease;
}

a:hover {
    color: var(--accent);
}

.container {
    width: 100%;
    max-width: 1140px;
    margin: 0 auto;
    padding: 0 16px;
}

/* 2. KaTeX Mathematics Typesetting (Protected against mobile overflow) */
.katex-display {
    overflow-x: auto;
    overflow-y: hidden;
    max-width: 100%;
    padding: 8px 0;
    margin: 14px 0;
    -webkit-overflow-scrolling: touch;
}

.katex {
    font-size: 1.05em;
    max-width: 100%;
}

/* 3. Top Identity Academy Header */
.academy-header {
    background: linear-gradient(135deg, #07172b 0%, #0b2545 100%);
    color: #ffffff;
    padding: 10px 0;
    border-bottom: 3px solid var(--accent);
}

.academy-header-inner {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 12px;
}

.academy-brand {
    display: flex;
    align-items: center;
    gap: 12px;
    color: #ffffff;
    text-decoration: none;
    min-width: 0;
    flex: 1 1 auto;
}

.academy-brand:hover {
    color: #ffffff;
}

.academy-logo {
    width: 48px;
    height: 48px;
    border-radius: 50%;
    border: 2px solid #ffd591;
    background: #ffffff;
    object-fit: cover;
    flex-shrink: 0;
}

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

.academy-dept {
    font-size: 10px;
    letter-spacing: 1.5px;
    font-weight: 700;
    color: #ffd591;
    text-transform: uppercase;
    line-height: 1.2;
}

.academy-name-full {
    font-size: 15px;
    font-weight: 800;
    color: #ffffff;
    letter-spacing: 0.3px;
    line-height: 1.3;
    display: block;
}

.academy-name-short {
    font-size: 14px;
    font-weight: 800;
    color: #ffffff;
    display: none;
    line-height: 1.3;
}

.academy-faculty-label {
    font-size: 11px;
    color: #cbd5e1;
    font-weight: 500;
    line-height: 1.2;
}

.academy-header-right {
    display: flex;
    align-items: center;
    gap: 8px;
    flex-shrink: 0;
}

.user-pill-clean {
    display: flex;
    align-items: center;
    gap: 8px;
    background: rgba(255, 255, 255, 0.12);
    padding: 4px 10px;
    border-radius: 20px;
    color: #ffffff;
    font-size: 13px;
    font-weight: 600;
    text-decoration: none;
}

.user-pill-clean:hover {
    background: rgba(255, 255, 255, 0.2);
    color: #ffffff;
}

.avatar-circle-sm {
    width: 28px;
    height: 28px;
    border-radius: 50%;
    background: var(--accent);
    color: #ffffff;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 12px;
    font-weight: 700;
    overflow: hidden;
}

.avatar-circle-sm img {
    width: 100%;
    height: 100%;
    object-fit: cover;
}

.auth-quick-actions {
    display: flex;
    align-items: center;
    gap: 6px;
}

.btn-xs {
    padding: 5px 10px;
    font-size: 12px;
    border-radius: var(--radius-sm);
    font-weight: 600;
    white-space: nowrap;
}

.mobile-nav-toggle {
    display: none;
    background: transparent;
    border: 1px solid rgba(255, 255, 255, 0.2);
    border-radius: var(--radius-sm);
    padding: 6px 8px;
    cursor: pointer;
}

.mobile-nav-toggle span {
    display: block;
    width: 20px;
    height: 2px;
    background-color: #ffffff;
    margin: 4px 0;
    transition: all 0.2s;
}

/* 4. Main Navigation Bar */
.main-nav {
    background: var(--bg-white);
    border-bottom: 1px solid var(--border);
    position: sticky;
    top: 0;
    z-index: 999;
}

.nav-inner {
    display: flex;
    align-items: center;
}

.nav-menu {
    display: flex;
    list-style: none;
    margin: 0;
    padding: 0;
    gap: 4px;
}

.nav-link {
    display: flex;
    align-items: center;
    gap: 6px;
    padding: 12px 14px;
    font-size: 14px;
    font-weight: 600;
    color: var(--text-main);
    border-bottom: 2px solid transparent;
    transition: all 0.15s ease;
}

.nav-link:hover, .nav-item.active .nav-link {
    color: var(--accent);
    border-bottom-color: var(--accent);
}

.nav-icon {
    width: 16px;
    height: 16px;
    flex-shrink: 0;
}

.mobile-only-auth {
    display: none;
}

/* 5. Buttons & Badges (Clean, Minimalist) */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 6px;
    font-weight: 600;
    border-radius: var(--radius-sm);
    border: 1px solid transparent;
    cursor: pointer;
    text-decoration: none;
    transition: all 0.15s ease;
    text-align: center;
}

.btn-primary {
    background-color: var(--accent);
    border-color: var(--accent);
    color: #ffffff;
}

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

.btn-gold {
    background-color: var(--gold);
    border-color: var(--gold);
    color: #ffffff;
}

.btn-gold:hover {
    background-color: #b37305;
    color: #ffffff;
}

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

.btn-outline:hover {
    border-color: var(--accent);
    color: var(--accent);
}

.btn-outline-light {
    background-color: transparent;
    border-color: rgba(255, 255, 255, 0.4);
    color: #ffffff;
}

.btn-outline-light:hover {
    background-color: rgba(255, 255, 255, 0.15);
    border-color: #ffffff;
    color: #ffffff;
}

.btn-link-light {
    background: transparent;
    border: none;
    color: #cbd5e1;
    text-decoration: underline;
}

.btn-outline-lock {
    background-color: #fffbe6;
    border-color: #ffe58f;
    color: #d48806;
    font-size: 13px;
    font-weight: 600;
    padding: 5px 10px;
}

.btn-outline-lock:hover {
    background-color: #fff1b8;
    color: #ad6800;
}

.btn-md {
    padding: 10px 18px;
    font-size: 14px;
}

.btn-sm {
    padding: 6px 12px;
    font-size: 13px;
}

.btn-lg {
    padding: 12px 20px;
    font-size: 15px;
}

.btn-block {
    display: flex;
    width: 100%;
}

.btn-icon {
    width: 16px;
    height: 16px;
}

.pill-badge {
    display: inline-block;
    font-size: 11px;
    font-weight: 700;
    padding: 3px 8px;
    border-radius: 4px;
    letter-spacing: 0.3px;
}

.pill-gold {
    background: #faad14;
    color: #000000;
}

.pill-outline {
    background: rgba(255, 255, 255, 0.12);
    color: #ffffff;
    border: 1px solid rgba(255, 255, 255, 0.25);
}

/* 6. Clean Flat Hero Section */
.hero-clean {
    background: linear-gradient(180deg, #0b2545 0%, #10325c 100%);
    color: #ffffff;
    padding: 36px 0 40px;
}

.hero-clean-inner {
    max-width: 820px;
}

.hero-badges-row {
    display: flex;
    gap: 8px;
    flex-wrap: wrap;
    margin-bottom: 14px;
}

.hero-clean-title {
    font-size: 30px;
    font-weight: 800;
    color: #ffffff;
    line-height: 1.3;
    margin: 0 0 14px;
}

.hero-clean-desc {
    font-size: 15px;
    color: #cbd5e1;
    line-height: 1.7;
    margin: 0 0 24px;
}

.hero-clean-actions {
    display: flex;
    gap: 10px;
    flex-wrap: wrap;
    align-items: center;
    margin-bottom: 28px;
}

/* Flat Stats Row (No cards, no borders, clean horizontal strip) */
.stats-flat-row {
    display: flex;
    align-items: center;
    gap: 16px;
    flex-wrap: wrap;
    padding-top: 18px;
    border-top: 1px solid rgba(255, 255, 255, 0.15);
}

.stat-flat-item {
    display: flex;
    align-items: baseline;
    gap: 6px;
}

.stat-flat-val {
    font-size: 20px;
    font-weight: 800;
    color: #ffd591;
}

.stat-flat-lbl {
    font-size: 13px;
    color: #cbd5e1;
}

.stat-flat-sep {
    color: rgba(255, 255, 255, 0.3);
    font-size: 12px;
}

/* 7. Guest Notice Strip */
.guest-strip {
    background: #fffbe6;
    border-bottom: 1px solid #ffe58f;
    padding: 12px 0;
    font-size: 14px;
    color: #874d00;
}

.guest-strip-inner {
    display: flex;
    align-items: flex-start;
    gap: 10px;
}

.guest-strip-icon {
    font-size: 18px;
    flex-shrink: 0;
}

.guest-strip-text {
    margin: 0;
    line-height: 1.5;
}

.guest-strip-text a {
    color: var(--accent);
    text-decoration: underline;
}

/* 8. Section General */
.section {
    padding: 40px 0;
}

.section-title-wrap {
    margin-bottom: 28px;
}

.section-title-wrap.text-center {
    text-align: center;
}

.sub-label {
    display: inline-block;
    font-size: 11px;
    font-weight: 700;
    color: var(--accent);
    letter-spacing: 1px;
    text-transform: uppercase;
    margin-bottom: 4px;
}

.main-title {
    font-size: 24px;
    font-weight: 800;
    color: var(--primary);
    margin: 0 0 8px;
    line-height: 1.35;
}

.desc-text {
    font-size: 14px;
    color: var(--text-muted);
    margin: 0;
    line-height: 1.6;
}

/* 9. Faculty Section (Clean & Flat, No Double-Box Inception) */
.faculty-clean-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 28px;
    align-items: start;
}

.faculty-photo-wrap {
    background: #ffffff;
    border-radius: var(--radius-md);
    overflow: hidden;
    border: 1px solid var(--border);
}

.faculty-photo-img {
    width: 100%;
    height: auto;
    object-fit: cover;
    display: block;
}

.photo-caption {
    padding: 10px 14px;
    margin: 0;
    font-size: 12px;
    font-weight: 600;
    color: var(--text-muted);
    background: #f8fafc;
    border-top: 1px solid var(--border);
}

.faculty-info-wrap {
    display: flex;
    flex-direction: column;
    gap: 16px;
}

.role-desc-box h3 {
    font-size: 18px;
    font-weight: 800;
    color: var(--primary);
    margin: 0 0 8px;
}

.role-desc-box p {
    font-size: 14px;
    color: var(--text-main);
    line-height: 1.65;
    margin: 0;
}

.teachers-clean-list h4 {
    font-size: 14px;
    font-weight: 700;
    color: var(--primary);
    margin: 0 0 10px;
}

.teacher-clean-row {
    display: flex;
    align-items: center;
    gap: 12px;
    padding: 8px 0;
    border-bottom: 1px solid var(--border-light);
}

.teacher-clean-avatar {
    width: 36px;
    height: 36px;
    border-radius: 50%;
    background: var(--primary);
    color: #ffd591;
    font-weight: 800;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 12px;
    flex-shrink: 0;
}

.teacher-clean-info {
    display: flex;
    flex-direction: column;
}

.teacher-clean-name {
    font-size: 14px;
    color: var(--primary);
}

.teacher-clean-pos {
    font-size: 12px;
    color: var(--text-muted);
}

.clean-link {
    font-size: 14px;
    font-weight: 600;
    color: var(--accent);
    text-decoration: underline;
}

/* 10. Curriculum Section (Flat Chapter List, No Heavy Box Enclosures) */
.chapters-clean-list {
    display: flex;
    flex-direction: column;
    gap: 24px;
}

.chapter-clean-block {
    background: var(--bg-white);
    border-radius: var(--radius-md);
    border: 1px solid var(--border);
    padding: 20px;
}

.chapter-clean-head {
    display: flex;
    align-items: baseline;
    justify-content: space-between;
    gap: 12px;
    margin-bottom: 8px;
}

.chapter-head-left {
    display: flex;
    align-items: center;
    gap: 8px;
    flex-wrap: wrap;
}

.ch-badge {
    background: var(--primary);
    color: #ffffff;
    font-weight: 700;
    font-size: 11px;
    padding: 2px 8px;
    border-radius: var(--radius-sm);
    text-transform: uppercase;
}

.ch-title {
    font-size: 18px;
    font-weight: 800;
    color: var(--primary);
    margin: 0;
}

.ch-meta {
    font-size: 12px;
    font-weight: 600;
    color: var(--text-muted);
    white-space: nowrap;
}

.chapter-clean-desc {
    font-size: 13px;
    color: var(--text-muted);
    margin: 0 0 16px;
    line-height: 1.6;
}

/* Flat Lesson Row */
.lessons-clean-list {
    display: flex;
    flex-direction: column;
    border-top: 1px solid var(--border-light);
}

.lesson-clean-row {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 14px;
    padding: 12px 0;
    border-bottom: 1px solid var(--border-light);
}

.lesson-clean-row:last-child {
    border-bottom: none;
}

.lesson-row-left {
    display: flex;
    align-items: center;
    gap: 12px;
    min-width: 0;
    flex: 1 1 auto;
}

.lesson-num-tag {
    font-size: 13px;
    font-weight: 800;
    color: var(--text-muted);
    background: #f1f5f9;
    width: 28px;
    height: 28px;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    flex-shrink: 0;
}

.lesson-title-meta {
    display: flex;
    flex-direction: column;
    gap: 3px;
    min-width: 0;
}

.lesson-clean-title {
    font-size: 14px;
    font-weight: 700;
    margin: 0;
    line-height: 1.4;
}

.lesson-clean-title a {
    color: var(--text-main);
}

.lesson-clean-title a:hover {
    color: var(--accent);
}

.lesson-tags-inline {
    display: flex;
    gap: 8px;
    font-size: 12px;
    color: var(--text-muted);
    flex-wrap: wrap;
    align-items: center;
}

.tag-inline-badge {
    background: #e0f2fe;
    color: #0369a1;
    font-weight: 600;
    padding: 1px 6px;
    border-radius: var(--radius-sm);
    font-size: 11px;
}

.lesson-row-action {
    flex-shrink: 0;
}

/* 11. Formula Section (Clean & Flat) */
.formula-clean-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(240px, 1fr));
    gap: 16px;
}

.formula-clean-item {
    background: var(--bg-white);
    border: 1px solid var(--border);
    border-radius: var(--radius-md);
    padding: 16px;
}

.formula-clean-item h4 {
    font-size: 14px;
    font-weight: 700;
    color: var(--primary);
    margin: 0 0 8px;
}

.katex-clean-display {
    text-align: center;
    padding: 6px 0;
}

.formula-clean-item p {
    font-size: 12px;
    color: var(--text-muted);
    margin: 8px 0 0;
    line-height: 1.5;
}

/* 12. Access Gate Screen (For unregistered visitors in lesson.php) */
.access-gate-wrap {
    max-width: 580px;
    margin: 20px auto;
    background: var(--bg-white);
    border: 1px solid var(--border);
    border-radius: var(--radius-md);
    padding: 32px 24px;
    text-align: center;
}

.access-gate-icon {
    font-size: 40px;
    margin-bottom: 12px;
}

.access-gate-badge {
    display: inline-block;
    font-size: 11px;
    font-weight: 700;
    color: var(--accent);
    background: #fff1f0;
    padding: 3px 10px;
    border-radius: 4px;
    margin-bottom: 12px;
    text-transform: uppercase;
}

.access-gate-title {
    font-size: 22px;
    font-weight: 800;
    color: var(--primary);
    margin: 0 0 8px;
}

.access-gate-lesson-title {
    font-size: 15px;
    color: var(--text-muted);
    margin: 0 0 16px;
}

.access-gate-desc {
    font-size: 14px;
    color: var(--text-main);
    line-height: 1.65;
    margin: 0 0 24px;
}

.access-gate-actions {
    display: flex;
    flex-direction: column;
    gap: 10px;
    margin-bottom: 24px;
}

.access-gate-meta {
    background: #f8fafc;
    border-radius: var(--radius-sm);
    padding: 16px;
    text-align: left;
    font-size: 13px;
}

.access-gate-meta h4 {
    font-size: 13px;
    color: var(--primary);
    margin: 0 0 8px;
}

.gate-meta-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 8px;
    color: var(--text-muted);
}

/* 13. Clean Lesson Reading Canvas (Flat, No Card Inceptions) */
.lesson-slim-bar {
    background: #0f2b48;
    color: #ffffff;
    padding: 10px 0 0;
    position: sticky;
    top: 48px;
    z-index: 990;
}

.lesson-slim-inner {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 12px;
    padding-bottom: 8px;
}

.lesson-crumbs-flat {
    font-size: 12px;
    color: #94a3b8;
    white-space: nowrap;
    overflow: hidden;
    text-overflow: ellipsis;
}

.lesson-crumbs-flat a {
    color: #cbd5e1;
    text-decoration: none;
}

.lesson-indicators-flat {
    display: flex;
    align-items: center;
    gap: 12px;
    font-size: 12px;
    flex-shrink: 0;
}

.timer-flat {
    background: rgba(255, 255, 255, 0.12);
    padding: 2px 8px;
    border-radius: 12px;
}

.card-num-flat {
    color: #ffd591;
    font-weight: 600;
}

.slim-progress-track {
    width: 100%;
    height: 3px;
    background: rgba(255, 255, 255, 0.15);
}

.slim-progress-bar {
    height: 100%;
    background: #faad14;
    transition: width 0.25s ease;
}

.lesson-canvas-container {
    max-width: 860px;
    margin: 0 auto;
    padding-top: 20px;
    padding-bottom: 60px;
}

.lesson-canvas-main {
    background: var(--bg-white);
    border-radius: var(--radius-md);
    border: 1px solid var(--border);
    padding: 28px 24px;
}

.study-article {
    display: none;
}

.study-article.active {
    display: block;
    animation: fadeIn 0.2s ease;
}

@keyframes fadeIn {
    from { opacity: 0; }
    to { opacity: 1; }
}

.article-top-meta {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 12px;
}

.article-badge {
    font-size: 11px;
    font-weight: 700;
    color: var(--accent);
    background: #fff1f0;
    padding: 2px 8px;
    border-radius: 3px;
    text-transform: uppercase;
}

.article-index {
    font-size: 12px;
    color: var(--text-muted);
}

.article-heading {
    font-size: 22px;
    font-weight: 800;
    color: var(--primary);
    margin: 0 0 18px;
    line-height: 1.35;
}

.article-body {
    font-size: 15px;
    line-height: 1.8;
}

.article-body p {
    margin-bottom: 14px;
}

/* Clean Callout Blocks (Single left accent bar, no double borders) */
.callout {
    padding: 12px 16px;
    border-radius: 0 var(--radius-sm) var(--radius-sm) 0;
    margin: 16px 0;
    border-left: 3px solid;
    font-size: 14px;
}

.callout-fire {
    background-color: #fff1f0;
    border-left-color: var(--accent);
}

.callout-fire h4 {
    color: var(--accent);
    margin: 0 0 4px;
    font-size: 14px;
}

.callout-warning {
    background-color: #fffbe6;
    border-left-color: var(--gold);
}

.callout-warning h4 {
    color: #ad6800;
    margin: 0 0 4px;
    font-size: 14px;
}

.callout-danger {
    background-color: #fff1f0;
    border-left-color: #cf1322;
}

.example-box {
    background-color: #f6ffed;
    border-left: 3px solid #52c41a;
    padding: 14px 16px;
    margin: 16px 0;
}

.example-box h4 {
    color: #237804;
    margin: 0 0 8px;
    font-size: 14px;
}

.math-block {
    background: #f8fafc;
    border-left: 3px solid var(--primary);
    padding: 14px 16px;
    margin: 16px 0;
}

.math-block h4 {
    color: var(--primary);
    margin: 0 0 6px;
    font-size: 14px;
}

.grid-cards-mini {
    display: flex;
    flex-direction: column;
    gap: 8px;
    margin: 14px 0;
}

.card-mini {
    background: #f8fafc;
    padding: 10px 14px;
    border-left: 2px solid #cbd5e1;
}

.card-mini h5 {
    color: var(--primary);
    margin: 0 0 3px;
    font-size: 13px;
}

.card-mini p {
    margin: 0;
    font-size: 13px;
}

.formula-list {
    padding-left: 20px;
    margin: 14px 0;
}

.formula-list li {
    margin-bottom: 10px;
}

/* Slim Deck Controls */
.deck-controls-flat {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 12px;
    margin-top: 24px;
    padding-top: 16px;
    border-top: 1px solid var(--border-light);
}

.deck-dots {
    display: flex;
    gap: 6px;
    align-items: center;
}

.deck-dot {
    width: 8px;
    height: 8px;
    border-radius: 50%;
    background: #cbd5e1;
    border: none;
    padding: 0;
    cursor: pointer;
    transition: all 0.2s;
}

.deck-dot.active {
    background: var(--accent);
    transform: scale(1.4);
}

.swipe-hint {
    font-size: 12px;
    color: var(--text-muted);
    text-align: center;
    margin: 12px 0 0;
}

.deck-finish-banner {
    background: #f0fdf4;
    border-left: 4px solid #22c55e;
    padding: 16px 20px;
    margin-top: 24px;
}

.finish-text h3 {
    font-size: 16px;
    color: #15803d;
    margin: 0 0 4px;
}

.finish-text p {
    font-size: 13px;
    color: var(--text-main);
    margin: 0;
}

/* 14. Flat Quiz Section */
.quiz-flat-section {
    margin-top: 36px;
    padding-top: 24px;
    border-top: 2px solid var(--border);
}

.quiz-flat-head {
    margin-bottom: 20px;
}

.quiz-flat-title {
    font-size: 18px;
    font-weight: 800;
    color: var(--primary);
    margin: 6px 0;
}

.quiz-flat-desc {
    font-size: 13px;
    color: var(--text-muted);
    margin: 0;
}

.quiz-flat-question {
    padding: 14px 0;
    border-bottom: 1px solid var(--border-light);
}

.q-flat-title {
    font-size: 14px;
    font-weight: 700;
    color: var(--primary);
    margin-bottom: 10px;
}

.q-flat-options {
    display: flex;
    flex-direction: column;
    gap: 6px;
}

.q-flat-label {
    display: flex;
    align-items: center;
    gap: 10px;
    padding: 10px 12px;
    background: #f8fafc;
    border-radius: var(--radius-sm);
    cursor: pointer;
    font-size: 14px;
    transition: background-color 0.15s;
}

.q-flat-label:hover {
    background: #f1f5f9;
}

.q-flat-label.correct {
    background: #f6ffed !important;
    color: #237804;
    font-weight: 600;
}

.q-flat-label.incorrect {
    background: #fff1f0 !important;
    color: #cf1322;
}

.q-flat-expl {
    margin-top: 10px;
    padding: 10px 14px;
    background: #e6f7ff;
    border-left: 3px solid #1890ff;
    font-size: 13px;
}

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

.quiz-flat-result {
    margin-top: 20px;
    padding: 18px;
    background: #f6ffed;
    border-radius: var(--radius-sm);
    text-align: center;
}

.score-big {
    font-size: 28px;
    font-weight: 800;
    color: #389e0d;
}

.score-small {
    font-size: 14px;
    color: var(--text-muted);
}

/* 15. Lesson Switch Bar (Bottom) */
.lesson-switch-bar {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 12px;
    margin-top: 32px;
    padding-top: 18px;
    border-top: 1px solid var(--border-light);
}

.switch-link {
    font-size: 13px;
    display: flex;
    flex-direction: column;
    max-width: 260px;
}

.switch-sub {
    font-size: 11px;
    color: var(--text-muted);
}

.switch-title {
    font-weight: 700;
    color: var(--primary);
    white-space: nowrap;
    overflow: hidden;
    text-overflow: ellipsis;
}

.switch-center-btn {
    font-size: 12px;
    font-weight: 600;
    color: var(--text-muted);
    padding: 4px 10px;
    background: #f1f5f9;
    border-radius: var(--radius-sm);
}

/* 16. Search View (Clean & Flat) */
.search-clean-box {
    max-width: 720px;
    margin: 0 auto 30px;
}

.search-input-wrap {
    display: flex;
    gap: 8px;
}

.search-clean-input {
    flex: 1 1 auto;
    padding: 10px 14px;
    font-size: 15px;
    border: 1px solid var(--border);
    border-radius: var(--radius-sm);
    outline: none;
    font-family: inherit;
}

.search-clean-input:focus {
    border-color: var(--primary);
}

.search-clean-tags {
    display: flex;
    gap: 8px;
    flex-wrap: wrap;
    align-items: center;
    font-size: 12px;
    margin-top: 10px;
}

.tags-hint {
    color: var(--text-muted);
}

.search-clean-tags a {
    color: var(--text-main);
    background: #f1f5f9;
    padding: 2px 8px;
    border-radius: var(--radius-sm);
}

.results-flat-list {
    display: flex;
    flex-direction: column;
    background: var(--bg-white);
    border: 1px solid var(--border);
    border-radius: var(--radius-md);
}

.result-flat-row {
    display: flex;
    align-items: flex-start;
    justify-content: space-between;
    gap: 14px;
    padding: 16px 20px;
    border-bottom: 1px solid var(--border-light);
}

.result-flat-row:last-child {
    border-bottom: none;
}

.result-flat-title {
    font-size: 15px;
    font-weight: 700;
    margin: 4px 0 8px;
}

.matched-item-flat {
    font-size: 13px;
    background: #f8fafc;
    padding: 6px 10px;
    margin-top: 6px;
    border-left: 2px solid var(--accent);
}

.matched-item-flat p {
    margin: 2px 0 0;
    color: var(--text-muted);
}

/* 17. Auth & Profile Forms (Clean & Responsive) */
.auth-clean-wrap {
    max-width: 480px;
    margin: 30px auto;
    background: var(--bg-white);
    border: 1px solid var(--border);
    border-radius: var(--radius-md);
    padding: 28px 20px;
}

.form-group {
    margin-bottom: 14px;
}

.form-group label {
    display: block;
    font-size: 13px;
    font-weight: 600;
    margin-bottom: 4px;
}

.form-control {
    width: 100%;
    padding: 9px 12px;
    font-size: 14px;
    border: 1px solid var(--border);
    border-radius: var(--radius-sm);
    font-family: inherit;
    outline: none;
}

.form-control:focus {
    border-color: var(--primary);
}

.form-grid-2 {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 12px;
}

/* 18. Footer */
.academy-footer {
    background: #07172b;
    color: #cbd5e1;
    margin-top: auto;
    border-top: 3px solid var(--accent);
    padding: 36px 0 20px;
    font-size: 13px;
}

.footer-flat-grid {
    display: grid;
    grid-template-columns: 1.5fr 1fr 1fr;
    gap: 30px;
    padding-bottom: 24px;
    border-bottom: 1px solid rgba(255, 255, 255, 0.1);
}

.footer-brand h4 {
    color: #ffffff;
    font-size: 15px;
    font-weight: 800;
    margin: 0 0 4px;
}

.footer-desc {
    color: #94a3b8;
    line-height: 1.6;
    margin: 8px 0 0;
    font-size: 12px;
}

.footer-col h5 {
    color: #ffffff;
    font-size: 14px;
    font-weight: 700;
    margin: 0 0 10px;
}

.footer-links-clean {
    list-style: none;
    padding: 0;
    margin: 0;
    display: flex;
    flex-direction: column;
    gap: 6px;
}

.footer-links-clean a {
    color: #94a3b8;
}

.footer-links-clean a:hover {
    color: #ffffff;
}

.footer-bottom-flat {
    padding-top: 16px;
    display: flex;
    justify-content: space-between;
    align-items: center;
    font-size: 12px;
    color: #64748b;
    flex-wrap: wrap;
    gap: 8px;
}


/* ==========================================================================
   18. AUTH, PROFILE, FORMS & TABLES (Clean Flat Mobile-Ready)
   ========================================================================== */

/* Alerts */
.alert {
    padding: 12px 16px;
    border-radius: var(--radius-sm);
    font-size: 14px;
    margin-bottom: 18px;
    line-height: 1.5;
}
.alert-danger {
    background-color: #fff1f0;
    border: 1px solid #ffa39e;
    color: #cf1322;
}
.alert-success {
    background-color: #f6ffed;
    border: 1px solid #b7eb8f;
    color: #389e0d;
}
.alert-warning {
    background-color: #fffbe6;
    border: 1px solid #ffe58f;
    color: #d48806;
}

/* Form Styles */
.form-group {
    margin-bottom: 16px;
    display: flex;
    flex-direction: column;
}
.form-group label {
    font-size: 13px;
    font-weight: 700;
    color: var(--primary);
    margin-bottom: 6px;
}
.form-group .required {
    color: var(--accent);
}
.form-control {
    width: 100%;
    padding: 10px 12px;
    font-size: 14px;
    color: var(--text-main);
    background-color: #ffffff;
    border: 1px solid var(--border);
    border-radius: var(--radius-sm);
    transition: border-color 0.15s ease, box-shadow 0.15s ease;
    box-sizing: border-box;
}
.form-control:focus {
    outline: none;
    border-color: var(--accent);
    box-shadow: 0 0 0 2px rgba(183, 28, 28, 0.12);
}
.file-input {
    padding: 7px 10px;
}
.form-row {
    display: flex;
    gap: 16px;
    margin-bottom: 0;
}
.form-row .col-md-6 {
    flex: 1 1 50%;
    min-width: 0;
}

/* Auth Cards */
.auth-page-container {
    max-width: 580px;
    margin: 40px auto;
}
.auth-card {
    background: #ffffff;
    border: 1px solid var(--border);
    border-radius: var(--radius-md);
    padding: 28px 24px;
}
.register-card {
    max-width: 720px;
    margin: 0 auto;
}
.auth-card-header {
    margin-bottom: 22px;
}
.auth-logo {
    width: 60px;
    height: 60px;
    border-radius: 50%;
    margin: 0 auto 12px;
    display: block;
    border: 2px solid #ffd591;
}
.auth-card-header h2 {
    font-size: 20px;
    font-weight: 800;
    color: var(--primary);
    margin: 0 0 6px;
}
.auth-card-header p {
    font-size: 13px;
    color: var(--text-muted);
    margin: 0;
}
.auth-card-footer {
    margin-top: 20px;
    padding-top: 14px;
    border-top: 1px solid var(--border-light);
    font-size: 13px;
    color: var(--text-muted);
}
.registration-note {
    background: #fffbe6;
    border: 1px solid #ffe58f;
    border-radius: var(--radius-sm);
    padding: 10px 14px;
    font-size: 13px;
    color: #874d00;
    margin: 14px 0;
}

/* Profile Page */
.profile-header-card {
    background: #ffffff;
    border: 1px solid var(--border);
    border-radius: var(--radius-md);
    padding: 24px;
    display: flex;
    align-items: center;
    gap: 20px;
    margin-bottom: 24px;
}
.profile-avatar-large {
    width: 72px;
    height: 72px;
    border-radius: 50%;
    background: var(--primary);
    color: #ffd591;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 28px;
    font-weight: 800;
    flex-shrink: 0;
    overflow: hidden;
}
.profile-avatar-large img {
    width: 100%;
    height: 100%;
    object-fit: cover;
}
.profile-main-info {
    flex: 1 1 auto;
    min-width: 0;
}
.profile-badges {
    display: flex;
    gap: 6px;
    margin-bottom: 6px;
}
.badge {
    display: inline-block;
    padding: 2px 8px;
    font-size: 11px;
    font-weight: 700;
    border-radius: var(--radius-sm);
}
.badge-primary {
    background: #e6f7ff;
    color: #096dd9;
    border: 1px solid #91d5ff;
}
.badge-gold {
    background: #fffbe6;
    color: #d48806;
    border: 1px solid #ffe58f;
}
.badge-success {
    background: #f6ffed;
    color: #389e0d;
    border: 1px solid #b7eb8f;
}
.profile-main-info h2 {
    font-size: 20px;
    font-weight: 800;
    color: var(--primary);
    margin: 0 0 10px;
}
.profile-meta-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 6px 16px;
    font-size: 13px;
    color: var(--text-muted);
}
.profile-meta-grid div strong {
    color: var(--text-main);
}

/* Metrics Summary Cards */
.hero-metrics {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 16px;
    margin: 20px 0;
}
.metric-card {
    background: #ffffff;
    border: 1px solid var(--border);
    border-radius: var(--radius-md);
    padding: 16px;
    display: flex;
    flex-direction: column;
    gap: 4px;
}
.metric-num {
    font-size: 22px;
    font-weight: 800;
    color: var(--accent);
}
.metric-label {
    font-size: 12px;
    color: var(--text-muted);
    font-weight: 600;
}

/* Profile Section Box & Table */
.profile-section-box {
    background: #ffffff;
    border: 1px solid var(--border);
    border-radius: var(--radius-md);
    padding: 20px;
    margin-top: 24px;
}
.box-title {
    font-size: 16px;
    font-weight: 800;
    color: var(--primary);
    margin: 0 0 16px;
}
.table-responsive {
    width: 100%;
    overflow-x: auto;
    -webkit-overflow-scrolling: touch;
}
.data-table {
    width: 100%;
    border-collapse: collapse;
    font-size: 13px;
    text-align: left;
}
.data-table th {
    background: #f8fafc;
    color: var(--primary);
    font-weight: 700;
    padding: 10px 12px;
    border-bottom: 2px solid var(--border);
    white-space: nowrap;
}
.data-table td {
    padding: 10px 12px;
    border-bottom: 1px solid var(--border-light);
    color: var(--text-main);
}
.data-table tr:hover td {
    background: #fdfefe;
}
.empty-text {
    font-size: 13px;
    color: var(--text-muted);
    font-style: italic;
    margin: 0;
}


/* ==========================================================================
   20. PROFESSIONAL ABOUT PAGE (HỌC VIỆN, KHOA K6, HỌC PHẦN 6.01, GIẢNG VIÊN)
   ========================================================================== */

/* Hero */
.about-hero {
    background: linear-gradient(135deg, #07172b 0%, #0b2545 60%, #164070 100%);
    color: #ffffff;
    padding: 36px 0 40px;
    border-bottom: 3px solid var(--accent);
}
.about-hero-inner {
    max-width: 900px;
}
.about-breadcrumb {
    display: flex;
    align-items: center;
    gap: 8px;
    font-size: 13px;
    color: #94a3b8;
    margin-bottom: 14px;
}
.about-breadcrumb a {
    color: #cbd5e1;
    text-decoration: underline;
}
.about-breadcrumb .curr {
    color: #ffd591;
    font-weight: 600;
}
.about-hero-title {
    font-size: 30px;
    font-weight: 800;
    color: #ffffff;
    line-height: 1.3;
    margin: 12px 0 14px;
}
.about-hero-desc {
    font-size: 15px;
    color: #cbd5e1;
    line-height: 1.7;
    margin: 0 0 24px;
}
.about-chips-row {
    display: flex;
    gap: 12px;
    flex-wrap: wrap;
    padding-top: 18px;
    border-top: 1px solid rgba(255, 255, 255, 0.15);
}
.about-chip {
    background: rgba(255, 255, 255, 0.08);
    border: 1px solid rgba(255, 255, 255, 0.18);
    padding: 6px 14px;
    border-radius: var(--radius-sm);
    display: flex;
    align-items: baseline;
    gap: 8px;
}
.chip-val {
    font-size: 18px;
    font-weight: 800;
    color: #ffd591;
}
.chip-lbl {
    font-size: 12px;
    color: #cbd5e1;
    text-transform: uppercase;
    letter-spacing: 0.5px;
}

/* In-Page Sub Navigation */
.about-subnav-sticky {
    position: sticky;
    top: 50px;
    z-index: 90;
    background: #ffffff;
    border-bottom: 1px solid var(--border);
    box-shadow: 0 2px 8px rgba(0, 0, 0, 0.04);
}
.about-subnav-list {
    list-style: none;
    padding: 0;
    margin: 0;
    display: flex;
    gap: 8px;
    overflow-x: auto;
    white-space: nowrap;
    -webkit-overflow-scrolling: touch;
    scrollbar-width: none;
}
.about-subnav-list::-webkit-scrollbar {
    display: none;
}
.about-subnav-link {
    display: block;
    padding: 12px 14px;
    font-size: 13px;
    font-weight: 700;
    color: var(--text-muted);
    border-bottom: 2px solid transparent;
    transition: all 0.15s ease;
}
.about-subnav-link:hover {
    color: var(--accent);
    border-bottom-color: var(--accent);
}

/* Main Body & Sections */
.about-main-body {
    padding: 36px 16px 60px;
}
.about-section {
    padding: 28px 0;
}
.about-divider {
    border: none;
    border-top: 1px solid var(--border);
    margin: 36px 0;
}
.about-section-header {
    margin-bottom: 22px;
}
.about-section-badge {
    display: inline-block;
    font-size: 11px;
    font-weight: 800;
    color: var(--accent);
    background: #fff1f0;
    border: 1px solid #ffa39e;
    padding: 3px 10px;
    border-radius: var(--radius-sm);
    letter-spacing: 0.5px;
    text-transform: uppercase;
    margin-bottom: 8px;
}
.about-section-title {
    font-size: 24px;
    font-weight: 800;
    color: var(--primary);
    margin: 0 0 6px;
    line-height: 1.35;
}
.about-section-subtitle {
    font-size: 14px;
    color: var(--text-muted);
    margin: 0;
    line-height: 1.6;
}
.about-prose {
    font-size: 15px;
    line-height: 1.8;
    color: var(--text-main);
}
.about-prose p {
    margin-bottom: 14px;
}
.subsection-title {
    font-size: 18px;
    font-weight: 800;
    color: var(--primary);
    margin: 28px 0 14px;
    padding-bottom: 6px;
    border-bottom: 1px solid var(--border-light);
}
.clean-bullet-list {
    padding-left: 20px;
    margin: 14px 0;
    line-height: 1.8;
}
.clean-bullet-list li {
    margin-bottom: 10px;
}

/* Pillar Grid */
.about-pillar-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
    gap: 18px;
}
.about-pillar-card {
    background: #ffffff;
    border: 1px solid var(--border);
    border-radius: var(--radius-md);
    padding: 20px;
    display: flex;
    flex-direction: column;
    gap: 8px;
    transition: transform 0.15s ease, border-color 0.15s ease;
}
.about-pillar-card:hover {
    border-color: #cbd5e1;
    transform: translateY(-2px);
}
.pillar-icon {
    font-size: 26px;
    line-height: 1;
}
.pillar-title {
    font-size: 15px;
    font-weight: 800;
    color: var(--primary);
    margin: 0;
}
.pillar-desc {
    font-size: 13px;
    color: var(--text-muted);
    line-height: 1.6;
    margin: 0;
}

/* Khoa K6 Banner */
.khoa-banner-wrapper {
    background: #ffffff;
    border: 1px solid var(--border);
    border-radius: var(--radius-md);
    overflow: hidden;
    margin: 20px 0;
}
.khoa-banner-img {
    width: 100%;
    height: auto;
    max-height: 480px;
    object-fit: cover;
    display: block;
}
.khoa-banner-caption {
    background: #f8fafc;
    border-top: 1px solid var(--border);
    padding: 12px 18px;
    font-size: 13px;
    color: var(--text-main);
    line-height: 1.5;
}
.khoa-banner-caption strong {
    color: var(--primary);
}
.khoa-banner-caption span {
    color: var(--text-muted);
}

/* Subject Clusters */
.subject-clusters-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 16px;
    margin-top: 16px;
}
.cluster-item {
    background: #ffffff;
    border: 1px solid var(--border);
    border-radius: var(--radius-md);
    padding: 18px;
    display: flex;
    gap: 16px;
    align-items: flex-start;
}
.cluster-num {
    background: #f0f5ff;
    color: #1d39c4;
    font-size: 16px;
    font-weight: 800;
    width: 38px;
    height: 38px;
    border-radius: var(--radius-sm);
    display: flex;
    align-items: center;
    justify-content: center;
    flex-shrink: 0;
}
.cluster-info h4 {
    font-size: 15px;
    font-weight: 800;
    color: var(--primary);
    margin: 0 0 6px;
    line-height: 1.35;
}
.cluster-info p {
    font-size: 13px;
    color: var(--text-muted);
    line-height: 1.6;
    margin: 0;
}

/* Course Specs Box */
.specs-box-card {
    background: #ffffff;
    border: 1px solid var(--border);
    border-radius: var(--radius-md);
    overflow: hidden;
    margin: 20px 0;
}
.specs-box-header {
    background: #f8fafc;
    border-bottom: 1px solid var(--border);
    padding: 12px 18px;
}
.specs-box-header h4 {
    font-size: 15px;
    font-weight: 800;
    color: var(--primary);
    margin: 0;
}
.specs-grid-meta {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 1px;
    background: var(--border-light);
}
.spec-cell {
    background: #ffffff;
    padding: 14px 18px;
    display: flex;
    flex-direction: column;
    gap: 4px;
}
.spec-cell-label {
    font-size: 12px;
    font-weight: 700;
    color: var(--text-muted);
    text-transform: uppercase;
    letter-spacing: 0.5px;
}
.spec-cell-value {
    font-size: 14px;
    color: var(--text-main);
    line-height: 1.5;
}

/* CLO Cards Grid */
.clo-cards-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 16px;
    margin-top: 16px;
}
.clo-card {
    background: #ffffff;
    border: 1px solid var(--border);
    border-radius: var(--radius-md);
    padding: 20px;
    display: flex;
    flex-direction: column;
    gap: 8px;
}
.clo-badge {
    font-size: 11px;
    font-weight: 800;
    padding: 2px 8px;
    border-radius: var(--radius-sm);
    display: inline-block;
    width: fit-content;
    text-transform: uppercase;
}
.clo-badge-k { background: #e6f7ff; color: #0050b3; border: 1px solid #91d5ff; }
.clo-badge-s { background: #f6ffed; color: #237804; border: 1px solid #b7eb8f; }
.clo-badge-a { background: #fffbe6; color: #ad6800; border: 1px solid #ffe58f; }
.clo-card h4 {
    font-size: 15px;
    font-weight: 800;
    color: var(--primary);
    margin: 0;
}
.clo-card p {
    font-size: 13px;
    color: var(--text-muted);
    line-height: 1.6;
    margin: 0;
}

/* Assessment Box */
.assessment-box {
    background: #ffffff;
    border: 1px solid var(--border);
    border-radius: var(--radius-md);
    padding: 20px;
}
.assessment-box h4 {
    font-size: 15px;
    font-weight: 800;
    color: var(--primary);
    margin: 0 0 14px;
}
.assessment-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 16px;
}
.assess-item {
    background: #f8fafc;
    border-radius: var(--radius-sm);
    padding: 16px;
    display: flex;
    gap: 14px;
    align-items: flex-start;
}
.assess-pct {
    font-size: 26px;
    font-weight: 800;
    color: var(--accent);
    line-height: 1;
    flex-shrink: 0;
}
.assess-info strong {
    font-size: 14px;
    color: var(--primary);
    display: block;
    margin-bottom: 4px;
}
.assess-info p {
    font-size: 13px;
    color: var(--text-muted);
    line-height: 1.5;
    margin: 0;
}

/* Faculty Profiles Grid */
.faculty-profiles-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 20px;
}
.faculty-profile-card {
    background: #ffffff;
    border: 1px solid var(--border);
    border-radius: var(--radius-md);
    overflow: hidden;
    display: flex;
    flex-direction: column;
}
.faculty-card-header {
    background: #f8fafc;
    border-bottom: 1px solid var(--border);
    padding: 18px;
    display: flex;
    align-items: center;
    gap: 14px;
}
.faculty-avatar-box {
    width: 52px;
    height: 52px;
    border-radius: 50%;
    background: linear-gradient(135deg, var(--primary) 0%, #164070 100%);
    color: #ffd591;
    font-size: 18px;
    font-weight: 800;
    display: flex;
    align-items: center;
    justify-content: center;
    flex-shrink: 0;
    border: 2px solid #ffd591;
}
.faculty-head-info {
    min-width: 0;
}
.faculty-rank-tag {
    font-size: 11px;
    font-weight: 700;
    color: var(--accent);
    text-transform: uppercase;
    letter-spacing: 0.5px;
    display: block;
    margin-bottom: 2px;
}
.faculty-title-text {
    font-size: 17px;
    font-weight: 800;
    color: var(--primary);
    margin: 0 0 2px;
    line-height: 1.3;
}
.faculty-role-tag {
    font-size: 12px;
    color: var(--text-muted);
    display: block;
}
.faculty-card-body {
    padding: 18px;
    display: flex;
    flex-direction: column;
    gap: 14px;
    flex: 1 1 auto;
}
.faculty-lead-bio {
    font-size: 13px;
    color: var(--text-main);
    line-height: 1.6;
    margin: 0;
    font-style: italic;
    background: #f8fafc;
    padding: 10px 12px;
    border-left: 3px solid var(--primary);
    border-radius: 0 var(--radius-sm) var(--radius-sm) 0;
}
.faculty-meta-list {
    display: flex;
    flex-direction: column;
    gap: 8px;
    font-size: 13px;
}
.f-meta-item {
    display: flex;
    flex-direction: column;
    gap: 2px;
}
.f-meta-lbl {
    font-weight: 700;
    color: var(--primary);
    font-size: 12px;
    text-transform: uppercase;
    letter-spacing: 0.3px;
}
.f-meta-val {
    color: var(--text-muted);
    line-height: 1.5;
}

/* Lab Experiments */
.lab-experiments-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 18px;
}
.lab-card {
    background: #ffffff;
    border: 1px solid var(--border);
    border-radius: var(--radius-md);
    overflow: hidden;
}
.lab-card-top {
    background: #f8fafc;
    border-bottom: 1px solid var(--border);
    padding: 14px 18px;
}
.lab-badge {
    display: inline-block;
    font-size: 11px;
    font-weight: 800;
    color: #1d39c4;
    background: #f0f5ff;
    border: 1px solid #adc6ff;
    padding: 2px 8px;
    border-radius: var(--radius-sm);
    margin-bottom: 6px;
}
.lab-title {
    font-size: 15px;
    font-weight: 800;
    color: var(--primary);
    margin: 0;
    line-height: 1.35;
}
.lab-card-body {
    padding: 16px 18px;
    display: flex;
    flex-direction: column;
    gap: 12px;
}
.lab-item-row strong {
    display: block;
    font-size: 12px;
    color: var(--primary);
    text-transform: uppercase;
    margin-bottom: 2px;
}
.lab-item-row p {
    font-size: 13px;
    color: var(--text-muted);
    line-height: 1.6;
    margin: 0;
}

/* Textbooks & References */
.textbooks-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 18px;
    margin-top: 14px;
}
.textbook-card {
    background: #ffffff;
    border: 1px solid var(--border);
    border-radius: var(--radius-md);
    padding: 18px;
    display: flex;
    flex-direction: column;
    gap: 6px;
}
.textbook-tag {
    display: inline-block;
    font-size: 10px;
    font-weight: 800;
    padding: 2px 8px;
    border-radius: var(--radius-sm);
    width: fit-content;
    text-transform: uppercase;
}
.tag-primary { background: #fff1f0; color: #cf1322; border: 1px solid #ffa39e; }
.tag-secondary { background: #e6f7ff; color: #096dd9; border: 1px solid #91d5ff; }
.textbook-title {
    font-size: 15px;
    font-weight: 800;
    color: var(--primary);
    margin: 4px 0 2px;
    line-height: 1.35;
}
.textbook-author {
    font-size: 13px;
    color: var(--text-main);
    margin: 0;
}
.textbook-publisher {
    font-size: 12px;
    color: var(--text-muted);
    font-style: italic;
    margin: 0;
}
.textbook-desc {
    font-size: 13px;
    color: var(--text-muted);
    line-height: 1.5;
    margin-top: 6px;
}

/* Ref Standards */
.ref-standards-list {
    display: flex;
    flex-direction: column;
    gap: 10px;
    margin-top: 14px;
}
.ref-item {
    background: #ffffff;
    border: 1px solid var(--border);
    border-radius: var(--radius-md);
    padding: 12px 16px;
    display: flex;
    gap: 12px;
    align-items: flex-start;
}
.ref-icon {
    font-size: 20px;
    line-height: 1;
    flex-shrink: 0;
}
.ref-text {
    font-size: 13px;
    color: var(--text-main);
    line-height: 1.6;
}
.ref-text strong {
    color: var(--primary);
}

/* Call to action */
.about-cta-banner {
    background: linear-gradient(135deg, #0b2545 0%, #164070 100%);
    color: #ffffff;
    border-radius: var(--radius-lg);
    padding: 36px 28px;
    text-align: center;
    border: 2px solid #ffd591;
}
.cta-inner h3 {
    font-size: 22px;
    font-weight: 800;
    color: #ffffff;
    margin: 0 0 10px;
}
.cta-inner p {
    font-size: 14px;
    color: #cbd5e1;
    max-width: 680px;
    margin: 0 auto 24px;
    line-height: 1.6;
}
.cta-actions {
    display: flex;
    justify-content: center;
    gap: 12px;
    flex-wrap: wrap;
}


/* ==========================================================================
   21. REDESIGNED SITE FOOTER (Prestigious, Academic, Balanced)
   ========================================================================== */

.site-footer {
    background: linear-gradient(180deg, #07172b 0%, #0b2545 100%);
    color: #cbd5e1;
    font-size: 14px;
    line-height: 1.6;
    margin-top: 50px;
    border-top: 3px solid var(--accent);
    position: relative;
}

.footer-top-accent {
    height: 3px;
    background: linear-gradient(90deg, var(--accent) 0%, #faad14 50%, #1677ff 100%);
    width: 100%;
}

.footer-main-container {
    padding: 44px 16px 36px;
}

.footer-grid {
    display: grid;
    grid-template-columns: 2.2fr 1.3fr 1.6fr 1.6fr;
    gap: 32px;
}

.footer-brand-header {
    display: flex;
    align-items: center;
    gap: 14px;
    margin-bottom: 14px;
}

.footer-emblem {
    width: 52px;
    height: 52px;
    border-radius: 50%;
    border: 2px solid #ffd591;
    background: #ffffff;
    object-fit: cover;
    flex-shrink: 0;
}

.footer-brand-titles {
    display: flex;
    flex-direction: column;
}

.footer-dept-tag {
    font-size: 10px;
    letter-spacing: 1.5px;
    font-weight: 700;
    color: #ffd591;
    text-transform: uppercase;
}

.footer-academy-name {
    font-size: 14px;
    font-weight: 800;
    color: #ffffff;
    margin: 0;
    line-height: 1.3;
}

.footer-faculty-name {
    font-size: 12px;
    color: #94a3b8;
    font-weight: 600;
}

.footer-mission-text {
    font-size: 13px;
    color: #94a3b8;
    line-height: 1.65;
    margin: 0 0 16px;
}

.footer-mission-text strong {
    color: #ffd591;
}

.footer-pill-specs {
    display: flex;
    gap: 8px;
    flex-wrap: wrap;
}

.footer-pill {
    background: rgba(255, 255, 255, 0.08);
    border: 1px solid rgba(255, 255, 255, 0.16);
    color: #ffd591;
    padding: 3px 8px;
    border-radius: var(--radius-sm);
    font-size: 11px;
    font-weight: 700;
    letter-spacing: 0.3px;
}

.footer-heading {
    font-size: 14px;
    font-weight: 800;
    color: #ffffff;
    text-transform: uppercase;
    letter-spacing: 0.5px;
    margin: 0 0 16px;
    padding-bottom: 8px;
    border-bottom: 2px solid rgba(255, 255, 255, 0.12);
}

.footer-nav-list {
    list-style: none;
    padding: 0;
    margin: 0;
    display: flex;
    flex-direction: column;
    gap: 8px;
    font-size: 13px;
}

.footer-nav-list a {
    color: #94a3b8;
    text-decoration: none;
    transition: color 0.15s ease, padding-left 0.15s ease;
    display: block;
}

.footer-nav-list a:hover {
    color: #ffffff;
    padding-left: 4px;
}

.footer-nav-list .highlight-link {
    color: #ffd591;
    font-weight: 700;
}

.footer-nav-list .highlight-link:hover {
    color: #ffffff;
}

.chapters-list span {
    color: #ffd591;
    font-weight: 700;
}

.footer-teachers-list {
    display: flex;
    flex-direction: column;
    gap: 10px;
}

.footer-teacher-item {
    background: rgba(255, 255, 255, 0.05);
    border-left: 3px solid #d48806;
    padding: 8px 10px;
    border-radius: 0 var(--radius-sm) var(--radius-sm) 0;
    display: flex;
    flex-direction: column;
}

.teacher-rank {
    font-size: 10px;
    color: #ffd591;
    font-weight: 700;
    text-transform: uppercase;
}

.teacher-name {
    font-size: 13px;
    color: #ffffff;
    font-weight: 700;
}

.teacher-role {
    font-size: 11px;
    color: #94a3b8;
}

.footer-bottom-bar {
    background: #040e1b;
    border-top: 1px solid rgba(255, 255, 255, 0.08);
    padding: 16px 0;
    font-size: 12px;
    color: #64748b;
}

.footer-bottom-flex {
    display: flex;
    justify-content: space-between;
    align-items: center;
    flex-wrap: wrap;
    gap: 10px;
}

.footer-bottom-left p {
    margin: 0;
}

.footer-bottom-left strong {
    color: #cbd5e1;
}

.footer-bottom-right strong {
    color: #ffd591;
}

/* ==========================================================================
   19. RESPONSIVE BREAKPOINTS (Mobile-First Polish)
   ========================================================================== */

@media (max-width: 768px) {
    .academy-header-inner {
        padding: 0 4px;
    }

    .academy-name-full {
        display: none;
    }

    .academy-name-short {
        display: block;
    }

    .academy-logo {
        width: 38px;
        height: 38px;
    }

    .mobile-nav-toggle {
        display: block;
    }

    .main-nav {
        border-bottom: none;
    }

    .nav-menu {
        display: none;
        flex-direction: column;
        width: 100%;
        background: var(--bg-white);
        border-bottom: 1px solid var(--border);
    }

    .nav-menu.open {
        display: flex;
    }

    .nav-link {
        padding: 12px 16px;
        border-bottom: 1px solid var(--border-light);
    }

    .mobile-only-auth {
        display: block;
    }

    .hero-clean {
        padding: 24px 0 28px;
    }

    .hero-clean-title {
        font-size: 22px;
    }

    .hero-clean-desc {
        font-size: 14px;
    }

    .faculty-clean-grid, .footer-flat-grid {
        grid-template-columns: 1fr;
    }

    .stats-flat-row {
        gap: 10px;
    }

    .stat-flat-val {
        font-size: 17px;
    }

    .stat-flat-lbl {
        font-size: 12px;
    }

    .chapter-clean-block {
        padding: 16px 12px;
    }

    .chapter-clean-head {
        flex-direction: column;
        align-items: flex-start;
        gap: 4px;
    }

    .lesson-clean-row {
        flex-direction: column;
        align-items: flex-start;
        gap: 10px;
    }

    .lesson-row-left {
        width: 100%;
    }

    .lesson-row-action {
        width: 100%;
    }

    .lesson-row-action .btn {
        width: 100%;
    }

    .lesson-canvas-main {
        padding: 20px 14px;
    }

    .article-heading {
        font-size: 18px;
    }

    .article-body {
        font-size: 14px;
    }

    .form-grid-2 {
        grid-template-columns: 1fr;
    }

    .gate-meta-grid {
        grid-template-columns: 1fr;
    }

    .footer-bottom-flat {
        flex-direction: column;
        align-items: flex-start;
    }

    
    .footer-grid {
        grid-template-columns: 1fr;
        gap: 24px;
    }
    .footer-brand-header {
        flex-direction: row;
        align-items: center;
    }
    .footer-bottom-flex {
        flex-direction: column;
        align-items: flex-start;
        gap: 6px;
    }

    .about-hero-title {
        font-size: 22px;
    }
    .about-hero-desc {
        font-size: 14px;
    }
    .about-chips-row {
        gap: 8px;
    }
    .about-chip {
        padding: 4px 10px;
    }
    .chip-val {
        font-size: 16px;
    }
    .about-subnav-list {
        gap: 4px;
    }
    .about-subnav-link {
        padding: 10px 12px;
        font-size: 12px;
    }
    .about-pillar-grid,
    .subject-clusters-grid,
    .specs-grid-meta,
    .clo-cards-grid,
    .assessment-grid,
    .faculty-profiles-grid,
    .lab-experiments-grid,
    .textbooks-grid {
        grid-template-columns: 1fr;
    }
    .cluster-item {
        flex-direction: column;
        gap: 10px;
    }
    .assess-item {
        flex-direction: column;
        gap: 8px;
    }
    .faculty-card-header {
        flex-direction: column;
        text-align: center;
    }
    .cta-actions {
        flex-direction: column;
    }
    .cta-actions .btn {
        width: 100%;
    }

    .form-row {
        flex-direction: column;
        gap: 0;
    }
    .form-row .col-md-6 {
        flex: 1 1 100%;
        width: 100%;
    }
    .profile-header-card {
        flex-direction: column;
        text-align: center;
        align-items: center;
    }
    .profile-badges {
        justify-content: center;
    }
    .profile-meta-grid {
        grid-template-columns: 1fr;
        text-align: left;
    }
    .hero-metrics {
        grid-template-columns: 1fr 1fr;
        gap: 10px;
    }
    .metric-card {
        padding: 12px;
    }
    .metric-num {
        font-size: 18px;
    }

}