* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    font-family: 'Inter', sans-serif;
    background-color: #fafbfd;
    color: #1e293b;
    line-height: 1.5;
}

.container {
    max-width: 1280px;
    margin: 0 auto;
    padding: 0 24px;
}

.site-header {
    background: #ffffff;
    border-bottom: 1px solid #eef2f6;
    position: sticky;
    top: 0;
    z-index: 100;
    backdrop-filter: blur(8px);
    background-color: rgba(255,255,255,0.92);
}

.header-inner {
    display: flex;
    align-items: center;
    justify-content: space-between;
    flex-wrap: wrap;
    padding: 16px 0;
}

.logo-area {
    display: flex;
    align-items: center;
    gap: 10px;
    cursor: pointer;
}

.logo-icon {
    background: linear-gradient(135deg, #3b82f6, #8b5cf6);
    width: 38px;
    height: 38px;
    border-radius: 12px;
    display: flex;
    align-items: center;
    justify-content: center;
    font-weight: 700;
    font-size: 22px;
    color: white;
}

.logo-text {
    font-size: 1.6rem;
    font-weight: 700;
    background: linear-gradient(120deg, #0f172a, #3b82f6);
    background-clip: text;
    -webkit-background-clip: text;
    color: transparent;
    letter-spacing: -0.3px;
}

.nav-links {
    display: flex;
    gap: 28px;
    font-weight: 500;
}

.nav-item {
    position: relative;
}

.nav-item > a {
    text-decoration: none;
    color: #334155;
    transition: 0.2s;
    display: flex;
    align-items: center;
    gap: 4px;
    padding: 8px 0;
}

.nav-item > a i {
    font-size: 0.7rem;
    transition: transform 0.2s;
}

.nav-item:hover > a i {
    transform: rotate(180deg);
}

.nav-item > a:hover, .nav-item > a.active {
    color: #3b82f6;
}

.dropdown-menu {
    position: absolute;
    top: 100%;
    left: 50%;
    transform: translateX(-50%) translateY(8px);
    background: white;
    border-radius: 16px;
    box-shadow: 0 20px 40px -8px rgba(0,0,0,0.15), 0 4px 12px rgba(0,0,0,0.05);
    border: 1px solid #eef2f6;
    min-width: 480px;
    opacity: 0;
    visibility: hidden;
    transition: all 0.25s cubic-bezier(0.4, 0, 0.2, 1);
    pointer-events: none;
    z-index: 1000;
    padding: 20px 0;
}

.nav-item:hover .dropdown-menu {
    opacity: 1;
    visibility: visible;
    transform: translateX(-50%) translateY(4px);
    pointer-events: auto;
}

.dropdown-menu::before {
    content: '';
    position: absolute;
    top: -6px;
    left: 50%;
    transform: translateX(-50%);
    width: 0;
    height: 0;
    border-left: 8px solid transparent;
    border-right: 8px solid transparent;
    border-bottom: 8px solid white;
    filter: drop-shadow(0 -2px 2px rgba(0,0,0,0.02));
}

.dropdown-content {
    display: flex;
    gap: 20px;
    padding: 0 20px;
}

.primary-categories {
    flex: 1;
    border-right: 1px solid #f1f5f9;
    padding-right: 20px;
    max-height: 360px;
    overflow-y: auto;
}

.primary-category-item {
    padding: 12px 16px;
    border-radius: 10px;
    cursor: pointer;
    transition: all 0.2s;
    display: flex;
    align-items: center;
    justify-content: space-between;
    color: #334155;
    font-weight: 500;
    font-size: 0.9rem;
    margin-bottom: 4px;
}

.primary-category-item i {
    font-size: 0.7rem;
    color: #94a3b8;
    opacity: 0;
    transition: opacity 0.2s;
}

.primary-category-item:hover {
    background: #f8fafc;
    color: #3b82f6;
}

.primary-category-item:hover i {
    opacity: 1;
    color: #3b82f6;
}

.primary-category-item.active {
    background: linear-gradient(135deg, #eff6ff 0%, #f8fafc 100%);
    color: #3b82f6;
    border-left: 3px solid #3b82f6;
}

.primary-category-item.active i {
    opacity: 1;
    color: #3b82f6;
}

.secondary-categories {
    flex: 1.2;
    padding-left: 4px;
    max-height: 360px;
    overflow-y: auto;
}

.secondary-category-item {
    padding: 10px 16px;
    border-radius: 8px;
    cursor: pointer;
    transition: all 0.2s;
    color: #475569;
    font-size: 0.85rem;
    margin-bottom: 2px;
}

.secondary-category-item:hover {
    background: #f8fafc;
    color: #3b82f6;
}

.secondary-category-item.all-item {
    font-weight: 600;
    color: #1e293b;
    border-bottom: 1px solid #f1f5f9;
    margin-bottom: 8px;
    padding-bottom: 12px;
}

.secondary-category-item.all-item i {
    margin-right: 6px;
    color: #3b82f6;
}

.hero-section {
    background: linear-gradient(120deg, #f1f5f9 0%, #ffffff 100%);
    padding: 48px 0 40px;
    border-bottom: 1px solid #e9edf2;
}
.hero-title {
    font-size: 2.5rem;
    font-weight: 700;
    background: linear-gradient(135deg, #0f172a, #2563eb);
    background-clip: text;
    -webkit-background-clip: text;
    color: transparent;
    margin-bottom: 12px;
}
.hero-sub {
    font-size: 1.1rem;
    color: #475569;
    max-width: 640px;
}

.categories-bar {
    display: flex;
    flex-wrap: wrap;
    gap: 12px;
    margin: 32px 0 24px 0;
    border-bottom: 1px solid #e2e8f0;
    padding-bottom: 12px;
}
.cat-btn {
    background: transparent;
    border: none;
    padding: 8px 20px;
    font-size: 0.95rem;
    font-weight: 500;
    border-radius: 40px;
    cursor: pointer;
    transition: all 0.2s;
    color: #475569;
    font-family: inherit;
}
.cat-btn:hover {
    background: #eef2ff;
    color: #1e40af;
}
.cat-btn.active {
    background: #3b82f6;
    color: white;
    box-shadow: 0 4px 8px rgba(59,130,246,0.2);
}

.sort-tabs {
    display: flex;
    gap: 8px;
    margin-bottom: 28px;
    border-bottom: 1px solid #eef2f6;
    padding-bottom: 10px;
}
.sort-item {
    padding: 6px 18px;
    font-size: 0.9rem;
    font-weight: 500;
    border-radius: 30px;
    cursor: pointer;
    transition: 0.2s;
    background: #f8fafc;
    color: #334155;
}
.sort-item.active {
    background: #1e293b;
    color: white;
}

.articles-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(360px, 1fr));
    gap: 28px;
    margin: 28px 0 40px;
}
.article-card {
    background: white;
    border-radius: 24px;
    box-shadow: 0 8px 20px rgba(0,0,0,0.02), 0 2px 6px rgba(0,0,0,0.05);
    transition: transform 0.2s, box-shadow 0.2s;
    overflow: hidden;
    border: 1px solid #edf2f7;
    display: flex;
    flex-direction: column;
    cursor: pointer;
}
.article-card:hover {
    transform: translateY(-4px);
    box-shadow: 0 20px 30px -12px rgba(0,0,0,0.12);
    border-color: #cbd5e1;
}
.card-content {
    padding: 24px 24px 20px;
    flex: 1;
}
.article-title {
    font-size: 1.3rem;
    font-weight: 700;
    line-height: 1.4;
    margin-bottom: 12px;
    color: #0f172a;
}
.article-summary {
    color: #475569;
    font-size: 0.9rem;
    line-height: 1.5;
    margin-bottom: 20px;
    display: -webkit-box;
    -webkit-line-clamp: 3;
    -webkit-box-orient: vertical;
    overflow: hidden;
}
.meta-info {
    display: flex;
    justify-content: space-between;
    align-items: center;
    font-size: 0.8rem;
    color: #64748b;
    border-top: 1px solid #f1f5f9;
    padding-top: 16px;
    margin-top: 8px;
}
.tag-group {
    display: flex;
    gap: 8px;
    flex-wrap: wrap;
    margin-bottom: 16px;
}
.tag {
    background: #f1f5f9;
    padding: 4px 10px;
    border-radius: 30px;
    font-size: 0.7rem;
    font-weight: 500;
    color: #334155;
}
.read-stats {
    display: flex;
    align-items: center;
    gap: 6px;
}
.pagination {
    display: flex;
    justify-content: center;
    align-items: center;
    gap: 12px;
    margin: 40px 0 70px;
    flex-wrap: wrap;
}
.page-btn {
    background: white;
    border: 1px solid #cbd5e1;
    padding: 8px 16px;
    border-radius: 40px;
    font-weight: 500;
    cursor: pointer;
    transition: 0.2s;
    font-family: inherit;
}
.page-btn.active-page {
    background: #3b82f6;
    border-color: #3b82f6;
    color: white;
}
.page-btn:disabled {
    opacity: 0.4;
    cursor: not-allowed;
}
.page-numbers {
    display: flex;
    gap: 8px;
}
.number-btn {
    background: transparent;
    border: none;
    width: 40px;
    height: 40px;
    border-radius: 40px;
    font-weight: 500;
    cursor: pointer;
    transition: 0.2s;
}
.number-btn.active-page {
    background: #3b82f6;
    color: white;
}
.loading {
    text-align: center;
    padding: 60px;
    color: #3b82f6;
    font-size: 1.2rem;
}

.coming-soon-container {
    background: white;
    border-radius: 28px;
    box-shadow: 0 8px 30px rgba(0,0,0,0.04);
    margin: 24px 0 48px;
    padding: 80px 40px;
    text-align: center;
    border: 1px solid #edf2f7;
    position: relative;
    overflow: hidden;
}

.coming-soon-container::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    height: 4px;
    background: linear-gradient(90deg, #3b82f6, #8b5cf6, #ec4899, #3b82f6);
    background-size: 300% 100%;
    animation: gradientShift 3s ease infinite;
}

@keyframes gradientShift {
    0%, 100% { background-position: 0% 50%; }
    50% { background-position: 100% 50%; }
}

.coming-soon-badge {
    display: inline-block;
    background: linear-gradient(135deg, #eff6ff, #e0e7ff);
    color: #3b82f6;
    font-weight: 600;
    font-size: 0.85rem;
    padding: 6px 18px;
    border-radius: 40px;
    margin-bottom: 24px;
    letter-spacing: 1px;
    border: 1px solid #bfdbfe;
}

.coming-soon-icon {
    font-size: 5rem;
    color: #3b82f6;
    margin-bottom: 24px;
    opacity: 0.8;
}

.coming-soon-title {
    font-size: 2.5rem;
    font-weight: 700;
    background: linear-gradient(135deg, #0f172a, #2563eb);
    background-clip: text;
    -webkit-background-clip: text;
    color: transparent;
    margin-bottom: 16px;
}

.coming-soon-subtitle {
    font-size: 1.1rem;
    color: #64748b;
    margin-bottom: 12px;
}

.coming-soon-status {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 8px;
    margin-top: 16px;
    color: #f59e0b;
    font-weight: 500;
}

.coming-soon-status i {
    font-size: 1rem;
}

.pulse-dot {
    width: 8px;
    height: 8px;
    background: #f59e0b;
    border-radius: 50%;
    animation: pulse 1.5s ease infinite;
}

@keyframes pulse {
    0%, 100% { opacity: 1; transform: scale(1); }
    50% { opacity: 0.5; transform: scale(1.2); }
}

.coming-soon-features {
    display: flex;
    justify-content: center;
    gap: 40px;
    margin-top: 48px;
    flex-wrap: wrap;
}

.feature-item {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 12px;
    padding: 20px 24px;
    background: #fafbfd;
    border-radius: 20px;
    min-width: 140px;
    transition: transform 0.2s;
}

.feature-item:hover {
    transform: translateY(-4px);
    background: #f1f5f9;
}

.feature-icon {
    width: 60px;
    height: 60px;
    background: linear-gradient(135deg, #eff6ff, #e0e7ff);
    border-radius: 20px;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.5rem;
    color: #3b82f6;
}

.feature-text {
    font-weight: 600;
    color: #334155;
    font-size: 0.9rem;
}

.feature-desc {
    font-size: 0.75rem;
    color: #94a3b8;
    margin-top: -4px;
}

footer {
    border-top: 1px solid #eef2f6;
    background: #ffffff;
    padding: 28px 0;
    text-align: center;
    color: #5b6e8c;
    font-size: 0.85rem;
}

@media (max-width: 720px) {
    .articles-grid {
        grid-template-columns: 1fr;
    }
    .hero-title {
        font-size: 1.8rem;
    }
    .dropdown-menu {
        min-width: 300px;
        left: 0;
        transform: translateX(0) translateY(8px);
    }
    .nav-item:hover .dropdown-menu {
        transform: translateX(0) translateY(4px);
    }
    .dropdown-menu::before {
        left: 30px;
    }
    .dropdown-content {
        flex-direction: column;
    }
    .primary-categories {
        border-right: none;
        border-bottom: 1px solid #f1f5f9;
        padding-right: 0;
        padding-bottom: 12px;
    }
    .coming-soon-title {
        font-size: 1.8rem;
    }
    .coming-soon-features {
        gap: 16px;
    }
    .feature-item {
        min-width: 120px;
        padding: 16px;
    }
}

.error-msg {
    background: #fee2e2;
    padding: 24px;
    border-radius: 20px;
    text-align: center;
    color: #b91c1c;
    margin: 30px 0;
}

.detail-full-container {
    background: white;
    border-radius: 28px;
    box-shadow: 0 8px 30px rgba(0,0,0,0.04);
    margin: 24px 0 48px;
    overflow: hidden;
    border: 1px solid #edf2f7;
}
.detail-header {
    padding: 32px 36px 20px 36px;
    border-bottom: 1px solid #eef2f6;
    background: #ffffff;
}
.detail-header h1 {
    font-size: 2rem;
    font-weight: 800;
    color: #0f172a;
    margin-bottom: 16px;
    line-height: 1.3;
}
.detail-meta {
    display: flex;
    flex-wrap: wrap;
    gap: 24px;
    font-size: 0.85rem;
    color: #5b6e8c;
    margin: 12px 0 8px;
}
.detail-tags {
    display: flex;
    flex-wrap: wrap;
    gap: 10px;
    margin-top: 14px;
}
.detail-tag {
    background: #f1f5f9;
    padding: 4px 14px;
    border-radius: 30px;
    font-size: 0.75rem;
    font-weight: 500;
    color: #334155;
}
.detail-body {
    padding: 32px 36px 48px;
    background: #fefefe;
}
.markdown-body {
    font-size: 1rem;
    line-height: 1.7;
    color: #1e293b;
}
.markdown-body pre {
    background: #0f172a;
    border-radius: 16px;
    padding: 1rem;
    overflow-x: auto;
}
.markdown-body code {
    font-family: 'Monaco', monospace;
    font-size: 0.85rem;
}
.back-to-list-btn {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    background: #f1f5f9;
    border: none;
    padding: 8px 20px;
    border-radius: 40px;
    font-weight: 500;
    font-size: 0.85rem;
    cursor: pointer;
    transition: 0.2s;
    color: #1e293b;
    margin-bottom: 24px;
}
.back-to-list-btn:hover {
    background: #e2e8f0;
    transform: translateX(-2px);
}
.author-card {
    margin-top: 32px;
    background: #f8fafc;
    border-radius: 24px;
    padding: 20px 24px;
    display: flex;
    align-items: center;
    gap: 16px;
    border: 1px solid #eef2f6;
}
.author-avatar {
    width: 52px;
    height: 52px;
    background: linear-gradient(135deg, #3b82f6, #8b5cf6);
    border-radius: 30px;
    display: flex;
    align-items: center;
    justify-content: center;
    color: white;
    font-size: 1.3rem;
}
.author-details h4 {
    font-size: 1rem;
    font-weight: 700;
    margin-bottom: 4px;
}
.author-details p {
    font-size: 0.8rem;
    color: #5b6e8c;
}

.breadcrumb-nav {
    display: flex;
    align-items: center;
    gap: 8px;
    padding: 16px 0;
    font-size: 0.85rem;
    color: #64748b;
    border-bottom: 1px solid #eef2f6;
    margin-bottom: 20px;
}
.breadcrumb-nav a {
    color: #3b82f6;
    text-decoration: none;
    cursor: pointer;
}
.breadcrumb-nav a:hover {
    text-decoration: underline;
}
.breadcrumb-nav i {
    font-size: 0.6rem;
    color: #cbd5e1;
}

.courses-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
    gap: 24px;
    margin: 28px 0 40px;
}
.course-card {
    background: white;
    border-radius: 20px;
    box-shadow: 0 8px 20px rgba(0,0,0,0.02), 0 2px 6px rgba(0,0,0,0.05);
    transition: transform 0.2s, box-shadow 0.2s;
    overflow: hidden;
    border: 1px solid #edf2f7;
    cursor: pointer;
    display: flex;
    flex-direction: column;
}
.course-card:hover {
    transform: translateY(-4px);
    box-shadow: 0 20px 30px -12px rgba(0,0,0,0.12);
    border-color: #cbd5e1;
}
.course-thumb {
    width: 100%;
    height: 160px;
    object-fit: cover;
    background: linear-gradient(135deg, #eff6ff, #e0e7ff);
}
.course-thumb-placeholder {
    width: 100%;
    height: 160px;
    display: flex;
    align-items: center;
    justify-content: center;
    background: linear-gradient(135deg, #eff6ff, #e0e7ff);
    font-size: 3rem;
    color: #3b82f6;
}
.course-card-body {
    padding: 20px;
    flex: 1;
    display: flex;
    flex-direction: column;
}
.course-card-title {
    font-size: 1.05rem;
    font-weight: 700;
    color: #0f172a;
    margin-bottom: 10px;
    line-height: 1.4;
    display: -webkit-box;
    -webkit-line-clamp: 2;
    -webkit-box-orient: vertical;
    overflow: hidden;
}
.course-card-desc {
    font-size: 0.82rem;
    color: #64748b;
    line-height: 1.5;
    flex: 1;
    display: -webkit-box;
    -webkit-line-clamp: 2;
    -webkit-box-orient: vertical;
    overflow: hidden;
    margin-bottom: 14px;
}
.course-card-meta {
    display: flex;
    justify-content: space-between;
    align-items: center;
    font-size: 0.78rem;
    color: #94a3b8;
    border-top: 1px solid #f1f5f9;
    padding-top: 12px;
}
.course-badge {
    display: inline-block;
    padding: 2px 10px;
    border-radius: 30px;
    font-size: 0.7rem;
    font-weight: 600;
}
.course-badge.required {
    background: #fef2f2;
    color: #dc2626;
}
.course-badge.elective {
    background: #f0fdf4;
    color: #16a34a;
}
.course-filter-tabs {
    display: flex;
    gap: 8px;
    margin-bottom: 8px;
}
.course-filter-tab {
    padding: 6px 18px;
    font-size: 0.9rem;
    font-weight: 500;
    border-radius: 30px;
    cursor: pointer;
    transition: 0.2s;
    background: #f8fafc;
    color: #334155;
    border: none;
    font-family: inherit;
}
.course-filter-tab.active {
    background: #1e293b;
    color: white;
}
.modal-overlay {
    position: fixed;
    top: 0; left: 0; right: 0; bottom: 0;
    background: rgba(15,23,42,0.6);
    z-index: 9999;
    display: flex;
    align-items: center;
    justify-content: center;
    animation: fadeIn 0.2s ease;
}
@keyframes fadeIn { from { opacity: 0; } to { opacity: 1; } }
.modal-dialog {
    background: #fff;
    border-radius: 16px;
    padding: 32px 28px 24px;
    width: 400px;
    max-width: 90vw;
    box-shadow: 0 20px 60px rgba(0,0,0,0.15);
    text-align: center;
}
.modal-dialog h3 { margin-bottom: 8px; font-size: 1.2rem; color: #0f172a; }
.modal-dialog p { margin-bottom: 20px; color: #64748b; font-size: 0.9rem; }
.modal-dialog .form-group { margin-bottom: 14px; text-align: left; }
.modal-dialog .form-group label { display: block; font-size: 0.8rem; font-weight: 600; color: #334155; margin-bottom: 4px; }
.modal-dialog .form-group input {
    width: 100%; padding: 10px 12px; border: 1px solid #d1d5db; border-radius: 8px;
    font-size: 0.9rem; font-family: inherit; outline: none; transition: 0.2s;
}
.modal-dialog .form-group input:focus { border-color: #3b82f6; box-shadow: 0 0 0 3px rgba(59,130,246,0.1); }
.modal-btn {
    width: 100%; padding: 11px; border: none; border-radius: 8px; font-size: 0.95rem;
    font-weight: 600; cursor: pointer; font-family: inherit; transition: 0.2s;
}
.modal-btn-primary { background: #3b82f6; color: #fff; margin-bottom: 8px; }
.modal-btn-primary:hover { background: #2563eb; }
.modal-btn-ghost { background: transparent; color: #64748b; font-size: 0.85rem; }
.modal-btn-ghost:hover { color: #334155; }
.modal-error { color: #ef4444; font-size: 0.8rem; margin-bottom: 8px; min-height: 20px; }
.course-hour-row { cursor: pointer; transition: 0.15s; border-radius: 6px; padding: 6px 8px; margin: 0 -8px; }
.course-hour-row:hover { background: #eef2ff; }
.nav-item-user { margin-left: auto; }
.user-panel { padding: 20px 24px; min-width: 280px; }
.user-panel-avatar { width: 56px; height: 56px; border-radius: 50%; background: linear-gradient(135deg, #3b82f6, #8b5cf6); display: flex; align-items: center; justify-content: center; color: #fff; font-size: 1.5rem; font-weight: 700; margin: 0 auto 10px; }
.user-panel-name { text-align: center; font-size: 0.95rem; font-weight: 600; color: #0f172a; margin-bottom: 14px; }
.user-panel-stats { display: flex; gap: 12px; margin-bottom: 16px; }
.user-panel-stat { flex: 1; background: #f8fafc; border-radius: 10px; padding: 12px 8px; text-align: center; }
.user-panel-stat-val { font-size: 1.1rem; font-weight: 700; color: #0f172a; }
.user-panel-stat-label { font-size: 0.7rem; color: #94a3b8; margin-top: 2px; }
.user-panel-actions { display: flex; gap: 8px; }
.user-panel-btn { flex: 1; padding: 9px 0; border-radius: 8px; border: none; font-size: 0.85rem; font-weight: 500; font-family: inherit; cursor: pointer; transition: 0.2s; text-align: center; text-decoration: none; }
.user-panel-btn-primary { background: #3b82f6; color: #fff; }
.user-panel-btn-primary:hover { background: #2563eb; }
.user-panel-btn-ghost { background: #f1f5f9; color: #334155; }
.user-panel-btn-ghost:hover { background: #e2e8f0; }
.user-panel-btn-danger { background: transparent; color: #94a3b8; font-size: 0.8rem; padding: 6px 0; }
.user-panel-btn-danger:hover { color: #ef4444; }
.user-panel-login-hint { text-align: center; color: #64748b; font-size: 0.85rem; margin-bottom: 14px; }

.video-overlay { display: none; position: fixed; top: 0; left: 0; width: 100%; height: 100%; background: rgba(0,0,0,0.92); z-index: 1000; flex-direction: column; align-items: center; justify-content: center; }
.video-overlay.active { display: flex; }
.video-close-btn { position: absolute; top: 20px; right: 28px; z-index: 1001; width: 44px; height: 44px; border-radius: 50%; border: 2px solid rgba(255,255,255,0.3); background: rgba(0,0,0,0.5); color: #fff; font-size: 20px; cursor: pointer; display: flex; align-items: center; justify-content: center; transition: all 0.2s; }
.video-close-btn:hover { background: rgba(239,68,68,0.9); border-color: #ef4444; }
.video-player-wrapper { width: 90%; max-width: 1100px; max-height: 85vh; }
.video-player-container { width: 100%; aspect-ratio: 16/9; background: #000; border-radius: 12px; overflow: hidden; }
.video-info-bar { display: flex; justify-content: space-between; align-items: center; padding: 12px 4px; color: #e2e8f0; font-size: 0.9rem; }
.video-next-btn { background: #3b82f6; color: #fff; border: none; padding: 8px 18px; border-radius: 8px; cursor: pointer; font-size: 0.85rem; transition: background 0.2s; }
.video-next-btn:hover { background: #2563eb; }
.video-next-btn:disabled { background: #475569; cursor: default; opacity: 0.6; }
.course-hour-row { cursor: pointer; transition: background 0.15s; border-radius: 6px; padding: 8px 6px; margin: 0 -6px; }
.course-hour-row:hover { background: #eef2ff; }
.course-hour-row.playing { background: #dbeafe; font-weight: 600; }