/* ==========================================================================
   SLIDE PLAYER CSS - TRÌNH CHIẾU BÀI GIẢNG TO RỘNG, CHUẨN FULLSCREEN & ÔN TẬP
   Khoa Nghiệp vụ cơ bản - Học viện PCCC và CNCH
   ========================================================================== */

/* Khung trang học tập mở rộng to rộng (Wide Layout) */
.lesson-container {
    max-width: 1560px !important;
    width: 96% !important;
    margin-left: auto;
    margin-right: auto;
    padding-left: 15px;
    padding-right: 15px;
}

/* Layout 2 cột: Menu bài học + Vùng học tập */
.lesson-layout-container {
    display: grid;
    grid-template-columns: 290px minmax(0, 1fr);
    gap: 22px;
    align-items: flex-start;
    margin-top: 15px;
    transition: all 0.3s ease;
}

.lesson-layout-container.sidebar-collapsed {
    grid-template-columns: minmax(0, 1fr);
}

.lesson-layout-container.sidebar-collapsed .curriculum-sidebar {
    display: none;
}

/* Sidebar Menu 16 bài học */
.curriculum-sidebar {
    background: #ffffff;
    border: 1px solid var(--border-color);
    border-radius: var(--radius-lg);
    box-shadow: 0 4px 15px rgba(0, 0, 0, 0.05);
    overflow: hidden;
    position: sticky;
    top: 75px;
    max-height: calc(100vh - 90px);
    display: flex;
    flex-direction: column;
    z-index: 90;
    transition: transform 0.3s ease, opacity 0.3s ease;
}

.curriculum-sidebar-header {
    background: linear-gradient(135deg, #1e3a8a 0%, #0f172a 100%);
    color: #ffffff;
    padding: 12px 16px;
    display: flex;
    justify-content: space-between;
    align-items: center;
    border-bottom: 2px solid var(--gold);
}

.curriculum-sidebar-header h3 {
    font-size: 14.5px;
    font-weight: 700;
    margin: 0;
    display: flex;
    align-items: center;
    gap: 6px;
}

.curriculum-sidebar-body {
    padding: 10px 12px;
    overflow-y: auto;
    flex-grow: 1;
    display: flex;
    flex-direction: column;
    gap: 12px;
}

.curriculum-chapter-group {
    border-bottom: 1px solid #f1f5f9;
    padding-bottom: 8px;
}

.curriculum-chapter-group:last-child {
    border-bottom: none;
    padding-bottom: 0;
}

.curriculum-chapter-title {
    font-size: 11.5px;
    font-weight: 800;
    color: var(--accent);
    text-transform: uppercase;
    letter-spacing: 0.3px;
    margin-bottom: 6px;
    display: flex;
    align-items: center;
    justify-content: space-between;
}

.curriculum-lessons-list {
    list-style: none;
    display: flex;
    flex-direction: column;
    gap: 4px;
    margin: 0;
    padding: 0;
}

.curriculum-lesson-item {
    display: block;
    text-decoration: none;
    padding: 8px 10px;
    border-radius: var(--radius-sm);
    color: var(--text-main);
    font-size: 12.5px;
    line-height: 1.35;
    transition: var(--transition);
    border: 1px solid transparent;
}

.curriculum-lesson-item:hover {
    background: #f1f5f9;
    color: var(--primary-light);
}

.curriculum-lesson-item.active {
    background: #eff6ff;
    border-color: #bfdbfe;
    color: var(--primary);
    font-weight: 700;
    border-left: 3px solid var(--accent);
}

.curriculum-lesson-meta {
    display: flex;
    justify-content: space-between;
    align-items: center;
    font-size: 10.5px;
    color: var(--text-muted);
    margin-top: 2px;
}

.curriculum-lesson-item.active .curriculum-lesson-meta {
    color: var(--primary-light);
}

/* Nút toggle Sidebar trên Desktop và Mobile */
.btn-toggle-sidebar {
    background: rgba(255, 255, 255, 0.15);
    color: #ffffff;
    border: 1px solid rgba(255, 255, 255, 0.3);
    padding: 6px 12px;
    border-radius: var(--radius-sm);
    font-size: 12.5px;
    font-weight: 600;
    cursor: pointer;
    display: inline-flex;
    align-items: center;
    gap: 5px;
    transition: var(--transition);
}

.btn-toggle-sidebar:hover {
    background: rgba(255, 255, 255, 0.25);
    border-color: #ffffff;
}

/* Mobile Floating Action Button (FAB) */
.mobile-curriculum-fab {
    display: none;
    position: fixed;
    bottom: 20px;
    right: 20px;
    z-index: 1050;
    background: linear-gradient(135deg, var(--accent) 0%, #b91c1c 100%);
    color: #ffffff;
    border: none;
    border-radius: 30px;
    padding: 10px 18px;
    box-shadow: 0 8px 20px rgba(220, 38, 38, 0.4);
    font-size: 13.5px;
    font-weight: 700;
    align-items: center;
    gap: 6px;
    cursor: pointer;
}

/* Backdrop mờ khi mở Drawer */
.sidebar-overlay {
    display: none;
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: rgba(15, 23, 42, 0.65);
    backdrop-filter: blur(3px);
    z-index: 1040;
}

.sidebar-overlay.active {
    display: block;
}

/* ==========================================================================
   SLIDE VIEWER CONTAINER: KHÔNG GIAN HỌC TẬP TO RỘNG & RÕ NÉT
   ========================================================================== */
.slide-viewer-wrapper {
    background: #070b14;
    border-radius: var(--radius-lg);
    box-shadow: 0 12px 35px rgba(0, 0, 0, 0.28);
    overflow: hidden;
    position: relative;
    border: 1px solid #1e293b;
    transition: all 0.25s ease;
}

/* Chiều cao rộng rãi 560px trên Desktop chuẩn */
.slide-canvas {
    position: relative;
    width: 100%;
    height: 560px;
    min-height: 540px;
    background: linear-gradient(135deg, #090d16 0%, #0f172a 60%, #1e1b4b 100%);
    color: #ffffff;
    overflow: hidden;
    touch-action: pan-y;
}

.slide-stage {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    display: flex;
    flex-direction: column;
    padding: 22px 32px;
    box-sizing: border-box;
    opacity: 0;
    visibility: hidden;
    transition: opacity 0.3s ease, transform 0.3s ease;
    transform: translateX(20px);
    overflow: hidden;
}

.slide-stage.active {
    opacity: 1;
    visibility: visible;
    transform: translateX(0);
}

.slide-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    border-bottom: 1px solid rgba(255, 255, 255, 0.12);
    padding-bottom: 10px;
    margin-bottom: 14px;
    flex-shrink: 0;
}

.slide-header-left {
    display: flex;
    align-items: center;
    gap: 10px;
}

.slide-unit-badge {
    background: var(--accent);
    color: #ffffff;
    padding: 4px 10px;
    border-radius: 4px;
    font-size: 11.5px;
    font-weight: 700;
    text-transform: uppercase;
    letter-spacing: 0.5px;
}

.slide-course-title {
    font-size: 13px;
    color: #94a3b8;
    font-weight: 600;
}

.slide-page-badge {
    background: rgba(255, 255, 255, 0.1);
    padding: 4px 12px;
    border-radius: 20px;
    font-size: 12px;
    font-weight: 700;
    color: #fde68a;
    border: 1px solid rgba(217, 119, 6, 0.3);
}

.slide-body {
    flex-grow: 1;
    display: grid;
    grid-template-columns: 1.35fr 0.65fr;
    gap: 24px;
    align-items: center;
    min-height: 0;
    overflow: hidden;
}

.slide-content-left {
    display: flex;
    flex-direction: column;
    justify-content: center;
    min-height: 0;
}

.slide-title {
    font-size: 24px;
    font-weight: 800;
    color: #ffffff;
    line-height: 1.3;
    margin: 0 0 5px 0;
    text-shadow: 0 2px 4px rgba(0, 0, 0, 0.5);
    letter-spacing: -0.2px;
}

.slide-subtitle {
    font-size: 14px;
    color: #38bdf8;
    font-weight: 600;
    margin-bottom: 12px;
}

.slide-points-list {
    list-style: none;
    display: flex;
    flex-direction: column;
    gap: 7px;
    margin: 0;
    padding: 0;
}

.slide-point-item {
    background: rgba(255, 255, 255, 0.05);
    border-left: 3.5px solid var(--gold);
    padding: 8px 12px;
    border-radius: 0 6px 6px 0;
    font-size: 13.5px;
    line-height: 1.48;
    color: #f1f5f9;
    backdrop-filter: blur(4px);
    transition: var(--transition);
}

.slide-point-item:hover {
    background: rgba(255, 255, 255, 0.09);
}

.slide-point-item strong {
    color: #fde047;
    font-weight: 700;
}

.slide-callout {
    margin-top: 10px;
    background: rgba(220, 38, 38, 0.16);
    border: 1px solid rgba(220, 38, 38, 0.45);
    padding: 7px 12px;
    border-radius: 6px;
    font-size: 12.5px;
    color: #fca5a5;
    display: flex;
    align-items: center;
    gap: 8px;
}

.slide-media-right {
    display: flex;
    justify-content: center;
    align-items: center;
    height: 100%;
    max-height: 380px;
}

.slide-media-right img {
    max-height: 320px;
    width: 100%;
    object-fit: cover;
    border-radius: var(--radius-md);
    box-shadow: 0 10px 25px rgba(0, 0, 0, 0.55);
    border: 1px solid rgba(255, 255, 255, 0.18);
}

/* ==========================================================================
   THANH ĐIỀU KHIỂN HỢP NHẤT: ĐIỀU HƯỚNG & THUYẾT MINH MP3
   ========================================================================== */
.slide-controls-bar {
    background: #0b1120;
    padding: 10px 20px;
    display: flex;
    justify-content: space-between;
    align-items: center;
    border-top: 1px solid rgba(255, 255, 255, 0.1);
    color: #ffffff;
    flex-wrap: wrap;
    gap: 10px;
}

.slide-nav-group, .slide-audio-group, .slide-tools-group {
    display: flex;
    align-items: center;
    gap: 8px;
}

.btn-ctrl {
    background: rgba(255, 255, 255, 0.1);
    color: #ffffff;
    border: 1px solid rgba(255, 255, 255, 0.2);
    padding: 7px 14px;
    border-radius: var(--radius-sm);
    font-size: 13.5px;
    font-weight: 600;
    cursor: pointer;
    transition: var(--transition);
    display: inline-flex;
    align-items: center;
    gap: 6px;
    user-select: none;
}

.btn-ctrl:hover:not(:disabled) {
    background: rgba(255, 255, 255, 0.2);
    border-color: #ffffff;
}

.btn-ctrl:disabled {
    opacity: 0.35;
    cursor: not-allowed;
}

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

.btn-ctrl-primary:hover:not(:disabled) {
    background: #2563eb;
    border-color: #2563eb;
}

.slide-counter-badge {
    font-size: 13px;
    font-weight: 700;
    color: #fde68a;
    margin: 0 4px;
    white-space: nowrap;
}

/* Nút Bật/Tắt thuyết minh MP3 duy nhất */
.btn-audio-pill {
    background: linear-gradient(135deg, #16a34a 0%, #15803d 100%);
    color: #ffffff;
    padding: 7px 16px;
    border-radius: 20px;
    font-size: 13px;
    font-weight: 700;
    border: none;
    cursor: pointer;
    display: inline-flex;
    align-items: center;
    gap: 7px;
    transition: all 0.2s;
    box-shadow: 0 2px 8px rgba(22, 163, 74, 0.3);
    user-select: none;
}

.btn-audio-pill:hover {
    box-shadow: 0 4px 12px rgba(22, 163, 74, 0.4);
    transform: translateY(-1px);
}

.btn-audio-pill.muted {
    background: #334155;
    color: #cbd5e1;
    box-shadow: none;
}

.btn-audio-pill.muted:hover {
    background: #475569;
}

.audio-mini-bars {
    display: inline-flex;
    align-items: flex-end;
    gap: 2px;
    height: 12px;
}

.audio-mini-bars span {
    width: 2.5px;
    height: 3px;
    background: #ffffff;
    border-radius: 1px;
    transition: height 0.15s ease;
}

.btn-audio-pill.playing .audio-mini-bars span:nth-child(1) {
    animation: waveBar 0.7s infinite alternate ease-in-out;
}

.btn-audio-pill.playing .audio-mini-bars span:nth-child(2) {
    animation: waveBar 0.5s infinite alternate ease-in-out 0.2s;
}

.btn-audio-pill.playing .audio-mini-bars span:nth-child(3) {
    animation: waveBar 0.8s infinite alternate ease-in-out 0.4s;
}

@keyframes waveBar {
    0% { height: 3px; }
    100% { height: 12px; }
}

.btn-ctrl-icon {
    background: rgba(255, 255, 255, 0.08);
    border: 1px solid rgba(255, 255, 255, 0.18);
    color: #ffffff;
    width: 34px;
    height: 34px;
    border-radius: var(--radius-sm);
    display: inline-flex;
    align-items: center;
    justify-content: center;
    font-size: 14.5px;
    cursor: pointer;
    transition: var(--transition);
}

.btn-ctrl-icon:hover {
    background: rgba(255, 255, 255, 0.2);
}

.btn-ctrl-text {
    background: rgba(255, 255, 255, 0.08);
    border: 1px solid rgba(255, 255, 255, 0.18);
    color: #cbd5e1;
    padding: 7px 12px;
    border-radius: var(--radius-sm);
    font-size: 12.5px;
    font-weight: 600;
    cursor: pointer;
    transition: var(--transition);
}

.btn-ctrl-text:hover {
    background: rgba(255, 255, 255, 0.15);
    color: #ffffff;
}

/* Nút Chuyển sang Câu hỏi ôn tập ở slide cuối */
.btn-ctrl-quiz-finish {
    background: linear-gradient(135deg, #16a34a 0%, #15803d 100%) !important;
    border-color: #16a34a !important;
    color: #ffffff !important;
    animation: pulseButton 1.6s infinite ease-in-out;
}

@keyframes pulseButton {
    0%, 100% {
        box-shadow: 0 0 0 0 rgba(22, 163, 74, 0.6);
    }
    50% {
        box-shadow: 0 0 0 8px rgba(22, 163, 74, 0);
    }
}

/* Thumbnails Filmstrip */
.slide-thumbs-drawer {
    background: #020617;
    padding: 10px 14px;
    display: flex;
    gap: 10px;
    overflow-x: auto;
    border-top: 1px solid rgba(255, 255, 255, 0.08);
}

.thumb-item {
    flex: 0 0 95px;
    height: 54px;
    background: #1e293b;
    border-radius: 4px;
    overflow: hidden;
    position: relative;
    cursor: pointer;
    border: 2px solid transparent;
    transition: var(--transition);
}

.thumb-item img {
    width: 100%;
    height: 100%;
    object-fit: cover;
    opacity: 0.6;
}

.thumb-item:hover img {
    opacity: 0.9;
}

.thumb-item.active {
    border-color: var(--gold);
    box-shadow: 0 0 8px rgba(217, 119, 6, 0.5);
}

.thumb-item.active img {
    opacity: 1;
}

.thumb-num {
    position: absolute;
    bottom: 2px;
    right: 3px;
    background: rgba(0, 0, 0, 0.75);
    color: #ffffff;
    font-size: 10px;
    padding: 1px 5px;
    border-radius: 2px;
    font-weight: 700;
}

/* ==========================================================================
   CHẾ ĐỘ TOÀN MÀN HÌNH (FULLSCREEN): CHỮ TO RÕ, ĐỒNG BỘ MỌI ĐỘ PHÂN GIẢI
   ========================================================================== */
#slide-viewer:fullscreen,
#slide-viewer:-webkit-full-screen,
#slide-viewer.is-fullscreen {
    width: 100vw !important;
    height: 100vh !important;
    max-width: 100vw !important;
    max-height: 100vh !important;
    border-radius: 0 !important;
    border: none !important;
    display: flex !important;
    flex-direction: column !important;
    justify-content: space-between !important;
    background: #060913 !important;
    z-index: 99999 !important;
    padding: 0 !important;
    margin: 0 !important;
}

#slide-viewer:fullscreen .slide-canvas,
#slide-viewer:-webkit-full-screen .slide-canvas,
#slide-viewer.is-fullscreen .slide-canvas {
    height: calc(100vh - 85px) !important;
    max-height: calc(100vh - 85px) !important;
    flex-grow: 1 !important;
}

#slide-viewer:fullscreen .slide-stage,
#slide-viewer:-webkit-full-screen .slide-stage,
#slide-viewer.is-fullscreen .slide-stage {
    padding: 3.5vh 4.5vw !important;
    justify-content: space-between !important;
}

#slide-viewer:fullscreen .slide-header,
#slide-viewer:-webkit-full-screen .slide-header,
#slide-viewer.is-fullscreen .slide-header {
    padding-bottom: 14px !important;
    margin-bottom: 18px !important;
    border-bottom: 2px solid rgba(255, 255, 255, 0.18) !important;
}

#slide-viewer:fullscreen .slide-unit-badge,
#slide-viewer:-webkit-full-screen .slide-unit-badge,
#slide-viewer.is-fullscreen .slide-unit-badge {
    font-size: 15px !important;
    padding: 6px 14px !important;
    letter-spacing: 0.6px !important;
}

#slide-viewer:fullscreen .slide-course-title,
#slide-viewer:-webkit-full-screen .slide-course-title,
#slide-viewer.is-fullscreen .slide-course-title {
    font-size: 17px !important;
    font-weight: 600 !important;
    color: #cbd5e1 !important;
}

#slide-viewer:fullscreen .slide-page-badge,
#slide-viewer:-webkit-full-screen .slide-page-badge,
#slide-viewer.is-fullscreen .slide-page-badge {
    font-size: 17px !important;
    padding: 6px 18px !important;
}

#slide-viewer:fullscreen .slide-body,
#slide-viewer:-webkit-full-screen .slide-body,
#slide-viewer.is-fullscreen .slide-body {
    gap: 4vw !important;
    flex-grow: 1 !important;
    grid-template-columns: 1.4fr 0.6fr !important;
}

#slide-viewer:fullscreen .slide-title,
#slide-viewer:-webkit-full-screen .slide-title,
#slide-viewer.is-fullscreen .slide-title {
    font-size: clamp(32px, 2.8vw, 48px) !important;
    line-height: 1.25 !important;
    margin-bottom: 10px !important;
    font-weight: 900 !important;
    letter-spacing: -0.4px !important;
}

#slide-viewer:fullscreen .slide-subtitle,
#slide-viewer:-webkit-full-screen .slide-subtitle,
#slide-viewer.is-fullscreen .slide-subtitle {
    font-size: clamp(18px, 1.35vw, 24px) !important;
    margin-bottom: 20px !important;
}

#slide-viewer:fullscreen .slide-points-list,
#slide-viewer:-webkit-full-screen .slide-points-list,
#slide-viewer.is-fullscreen .slide-points-list {
    gap: 14px !important;
}

#slide-viewer:fullscreen .slide-point-item,
#slide-viewer:-webkit-full-screen .slide-point-item,
#slide-viewer.is-fullscreen .slide-point-item {
    font-size: clamp(17px, 1.2vw, 24px) !important;
    line-height: 1.58 !important;
    padding: 14px 20px !important;
    border-left-width: 5px !important;
    border-radius: 0 8px 8px 0 !important;
}

#slide-viewer:fullscreen .slide-callout,
#slide-viewer:-webkit-full-screen .slide-callout,
#slide-viewer.is-fullscreen .slide-callout {
    font-size: clamp(16px, 1.1vw, 21px) !important;
    padding: 14px 20px !important;
    margin-top: 18px !important;
    border-radius: 8px !important;
}

#slide-viewer:fullscreen .slide-media-right,
#slide-viewer:-webkit-full-screen .slide-media-right,
#slide-viewer.is-fullscreen .slide-media-right {
    max-height: calc(100vh - 230px) !important;
}

#slide-viewer:fullscreen .slide-media-right img,
#slide-viewer:-webkit-full-screen .slide-media-right img,
#slide-viewer.is-fullscreen .slide-media-right img {
    max-height: calc(100vh - 250px) !important;
    border-radius: 14px !important;
    box-shadow: 0 16px 45px rgba(0, 0, 0, 0.75) !important;
}

#slide-viewer:fullscreen .slide-controls-bar,
#slide-viewer:-webkit-full-screen .slide-controls-bar,
#slide-viewer.is-fullscreen .slide-controls-bar {
    padding: 14px 35px !important;
    border-top: 1px solid rgba(255, 255, 255, 0.15) !important;
    background: #080d1a !important;
}

#slide-viewer:fullscreen .btn-ctrl,
#slide-viewer:-webkit-full-screen .btn-ctrl,
#slide-viewer.is-fullscreen .btn-ctrl {
    font-size: 16px !important;
    padding: 10px 20px !important;
    border-radius: 8px !important;
}

#slide-viewer:fullscreen .slide-counter-badge,
#slide-viewer:-webkit-full-screen .slide-counter-badge,
#slide-viewer.is-fullscreen .slide-counter-badge {
    font-size: 16px !important;
}

#slide-viewer:fullscreen .btn-audio-pill,
#slide-viewer:-webkit-full-screen .btn-audio-pill,
#slide-viewer.is-fullscreen .btn-audio-pill {
    font-size: 16px !important;
    padding: 10px 24px !important;
}

#slide-viewer:fullscreen .btn-ctrl-icon,
#slide-viewer:-webkit-full-screen .btn-ctrl-icon,
#slide-viewer.is-fullscreen .btn-ctrl-icon {
    width: 44px !important;
    height: 44px !important;
    font-size: 18px !important;
}

#slide-viewer:fullscreen .btn-ctrl-text,
#slide-viewer:-webkit-full-screen .btn-ctrl-text,
#slide-viewer.is-fullscreen .btn-ctrl-text {
    font-size: 15px !important;
    padding: 10px 18px !important;
}

/* ==========================================================================
   PHẦN CÂU HỎI ÔN TẬP: HIỆN Ở CUỐI, SAU KHI HỌC XONG MỚI MỞ RA
   ========================================================================== */
.quiz-unlock-box {
    background: #ffffff;
    border: 2px dashed #cbd5e1;
    border-radius: var(--radius-lg);
    padding: 24px 28px;
    margin-top: 30px;
    display: flex;
    align-items: center;
    gap: 20px;
    transition: all 0.3s ease;
}

.quiz-unlock-box.locked {
    background: #f8fafc;
    border-color: #cbd5e1;
}

.quiz-unlock-box.unlocked {
    background: linear-gradient(135deg, #f0fdf4 0%, #dcfce7 100%);
    border: 2px solid #22c55e;
    box-shadow: 0 6px 20px rgba(34, 197, 94, 0.15);
}

.quiz-unlock-icon {
    font-size: 38px;
    line-height: 1;
    flex-shrink: 0;
}

.quiz-unlock-info {
    flex-grow: 1;
}

.quiz-unlock-title {
    font-size: 18px;
    font-weight: 700;
    color: var(--primary);
    margin: 0 0 5px 0;
}

.quiz-unlock-desc {
    font-size: 14px;
    color: var(--text-muted);
    margin: 0 0 10px 0;
}

.quiz-prog-track {
    width: 100%;
    max-width: 420px;
    height: 8px;
    background: #e2e8f0;
    border-radius: 4px;
    overflow: hidden;
}

.quiz-prog-fill {
    height: 100%;
    background: linear-gradient(90deg, #2563eb, #16a34a);
    border-radius: 4px;
    transition: width 0.3s ease;
}

.quiz-unlock-status {
    padding: 6px 14px;
    border-radius: 20px;
    font-size: 12.5px;
    font-weight: 700;
    background: #f1f5f9;
    color: #64748b;
    border: 1px solid #e2e8f0;
    white-space: nowrap;
}

.quiz-unlock-status.completed {
    background: #22c55e;
    color: #ffffff;
    border-color: #22c55e;
    box-shadow: 0 2px 8px rgba(34, 197, 94, 0.3);
}

/* Khung câu hỏi ôn tập khi mở */
.quiz-review-section {
    background: #ffffff;
    border: 1px solid var(--border-color);
    border-radius: var(--radius-lg);
    padding: 28px;
    margin-top: 20px;
    box-shadow: var(--shadow-md);
    transition: all 0.3s ease;
}

/* Nút chọn số lượng câu hỏi tự sinh & Đổi đề mới */
.quiz-generator-toolbar {
    display: flex;
    align-items: center;
    gap: 8px;
    flex-wrap: wrap;
}

.btn-qnum {
    padding: 6px 14px;
    font-size: 13px;
    font-weight: 700;
    cursor: pointer;
    border: 1px solid #cbd5e1;
    background: #ffffff;
    color: var(--text-main);
    border-radius: var(--radius-sm);
    transition: all 0.2s ease;
}

.btn-qnum.active {
    background: var(--primary);
    border-color: var(--primary);
    color: #ffffff;
    box-shadow: 0 2px 6px rgba(30, 58, 138, 0.25);
}

.btn-qnum:hover:not(.active) {
    background: #f1f5f9;
    border-color: #94a3b8;
}

.btn-regen-quiz {
    background: #eff6ff;
    color: var(--primary);
    border: 1px solid #bfdbfe;
    padding: 6px 14px;
    border-radius: var(--radius-sm);
    font-size: 13px;
    font-weight: 700;
    cursor: pointer;
    display: inline-flex;
    align-items: center;
    gap: 5px;
    transition: all 0.2s ease;
}

.btn-regen-quiz:hover {
    background: #dbeafe;
    border-color: var(--primary);
}

.quiz-question-block {
    transition: all 0.2s ease;
}

.animated-fade-in {
    animation: fadeInUp 0.45s ease forwards;
}

@keyframes fadeInUp {
    from {
        opacity: 0;
        transform: translateY(20px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

/* Document Mode Container */
.doc-reader-wrapper {
    background: #ffffff;
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-sm);
    padding: 35px;
    border: 1px solid var(--border-color);
}

.doc-content {
    font-size: 15.5px;
    line-height: 1.75;
    color: var(--text-main);
}

.doc-content h2, .doc-content h3, .doc-content h4 {
    color: var(--primary);
    margin-top: 22px;
    margin-bottom: 12px;
}

.doc-content p {
    margin-bottom: 15px;
    text-align: justify;
}

/* Responsive cho màn hình điện thoại & tablet */
@media (max-width: 900px) {
    .lesson-layout-container {
        grid-template-columns: 1fr;
        gap: 15px;
    }
    .curriculum-sidebar {
        position: fixed;
        top: 0;
        left: 0;
        bottom: 0;
        width: 300px;
        max-height: 100vh;
        z-index: 1050;
        transform: translateX(-100%);
        box-shadow: 5px 0 25px rgba(0, 0, 0, 0.3);
    }
    .curriculum-sidebar.open {
        transform: translateX(0);
    }
    .mobile-curriculum-fab {
        display: inline-flex;
    }
}

@media (max-width: 768px) {
    .slide-canvas {
        height: auto;
        min-height: 480px;
    }
    .slide-stage {
        position: relative;
        height: auto;
        padding: 16px;
        transform: none;
        opacity: 0;
        display: none;
    }
    .slide-stage.active {
        display: flex;
        opacity: 1;
    }
    .slide-body {
        grid-template-columns: 1fr;
        gap: 14px;
    }
    .slide-media-right img {
        max-height: 180px;
    }
    .slide-title {
        font-size: 19px;
    }
    .slide-controls-bar {
        justify-content: center;
        gap: 6px;
        padding: 10px;
    }
    .slide-nav-group, .slide-audio-group, .slide-tools-group {
        justify-content: center;
    }
    .quiz-unlock-box {
        flex-direction: column;
        text-align: center;
        padding: 20px;
    }
    .quiz-prog-track {
        margin: 0 auto;
    }
    .doc-reader-wrapper {
        padding: 20px 14px;
        border-radius: 12px;
    }
}