/* ========================================
   课程学习页面样式
   ======================================== */

/* 年级选择器 - 分组样式 */
.grade-selector {
    display: flex;
    flex-wrap: wrap;
    gap: var(--spacing-md);
    padding: var(--spacing-lg);
    background: var(--bg-secondary);
    border-radius: var(--radius-xl);
    margin-bottom: var(--spacing-lg);
}

.grade-group-label {
    width: 100%;
    font-size: 13px;
    font-weight: 600;
    color: var(--text-secondary);
    margin-top: var(--spacing-sm);
    padding-left: var(--spacing-xs);
}
.grade-group-label:first-child { margin-top: 0; }

.grade-btn {
    display: flex;
    align-items: center;
    gap: 6px;
    padding: 10px 18px;
    border: 2px solid var(--border-color);
    border-radius: var(--radius-lg);
    background: white;
    cursor: pointer;
    transition: all var(--transition-fast);
    font-family: inherit;
    font-size: 14px;
    color: var(--text-secondary);
}

.grade-btn:hover {
    border-color: var(--primary-light);
    transform: translateY(-2px);
    box-shadow: var(--shadow-sm);
}

.grade-btn.active {
    border-color: var(--primary-color);
    background: linear-gradient(135deg, rgba(91, 155, 213, 0.08), rgba(139, 189, 233, 0.12));
    color: var(--primary-color);
    font-weight: 600;
}

.grade-icon { font-size: 18px; }
.grade-name { font-weight: 500; }

.courses-layout {
    display: grid;
    grid-template-columns: 280px 1fr;
    gap: var(--spacing-xl);
    margin-top: var(--spacing-lg);
}

/* 侧边栏 - 课程分类 */
.courses-sidebar {
    background: var(--bg-secondary);
    border-radius: var(--radius-lg);
    padding: var(--spacing-lg);
    box-shadow: var(--shadow-sm);
    height: fit-content;
    position: sticky;
    top: var(--spacing-xl);
}

.search-box {
    position: relative;
    margin-bottom: var(--spacing-lg);
}

.search-box input {
    width: 100%;
    padding: 10px 40px 10px 16px;
    border: 2px solid var(--border-color);
    border-radius: var(--radius-xl);
    font-size: 14px;
    outline: none;
    transition: border-color var(--transition-fast);
    font-family: inherit;
}

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

.search-icon {
    position: absolute;
    right: 14px;
    top: 50%;
    transform: translateY(-50%);
    pointer-events: none;
}

.subject-list {
    max-height: calc(100vh - 250px);
    overflow-y: auto;
}

.subject-category {
    margin-bottom: var(--spacing-lg);
}

.subject-category h4 {
    font-size: 13px;
    color: var(--text-muted);
    text-transform: uppercase;
    letter-spacing: 1px;
    margin-bottom: var(--spacing-md);
    font-weight: 600;
}

.subject-category ul {
    list-style: none;
}

.subject-item {
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
    padding: 12px var(--spacing-md);
    border-radius: var(--radius-md);
    cursor: pointer;
    transition: all var(--transition-fast);
    margin-bottom: var(--spacing-xs);
    font-size: 14px;
    color: var(--text-secondary);
}

.subject-item:hover {
    background: var(--bg-tertiary);
    color: var(--primary-color);
}

.subject-item.active {
    background: linear-gradient(135deg, rgba(91, 155, 213, 0.15), rgba(139, 189, 233, 0.2));
    color: var(--primary-color);
    font-weight: 600;
}

.subject-icon {
    font-size: 18px;
}

.chapter-count {
    margin-left: auto;
    font-size: 12px;
    color: var(--text-muted);
    background: var(--bg-tertiary);
    padding: 2px 8px;
    border-radius: 10px;
}

/* 主内容区 */
.course-content {
    flex: 1;
}

.breadcrumb {
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
    font-size: 14px;
    color: var(--text-muted);
    margin-bottom: var(--spacing-lg);
}

.breadcrumb .current {
    color: var(--primary-color);
    font-weight: 600;
}

.chapter-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    background: var(--bg-secondary);
    padding: var(--spacing-lg);
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-sm);
    margin-bottom: var(--spacing-lg);
}

.chapter-header h3 {
    font-size: 22px;
    color: var(--text-primary);
    font-weight: 700;
}

.chapter-progress-info {
    display: flex;
    align-items: center;
    gap: var(--spacing-md);
}

.chapter-progress-info span {
    font-size: 14px;
    color: var(--text-secondary);
}

.mini-progress {
    width: 100px;
    height: 6px;
    background: var(--border-color);
    border-radius: 3px;
    overflow: hidden;
}

.mini-progress .fill {
    height: 100%;
    background: linear-gradient(90deg, var(--accent-green), var(--success));
    border-radius: 3px;
}

/* 知识点卡片列表 */
.knowledge-points {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(320px, 1fr));
    gap: var(--spacing-lg);
    margin-bottom: var(--spacing-xl);
}

.kp-card {
    background: var(--bg-secondary);
    border-radius: var(--radius-lg);
    padding: var(--spacing-lg);
    box-shadow: var(--shadow-sm);
    border: 2px solid transparent;
    transition: all var(--transition-normal);
    position: relative;
    overflow: hidden;
}

.kp-card::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    width: 4px;
    height: 100%;
    background: var(--border-color);
    transition: background var(--transition-normal);
}

.kp-card:hover {
    transform: translateY(-4px);
    box-shadow: var(--shadow-md);
}

.kp-card.completed::before {
    background: var(--success);
}

.kp-card.in-progress::before {
    background: var(--primary-color);
}

.kp-card.locked::before {
    background: var(--text-muted);
}

.kp-card.completed {
    opacity: 0.9;
}

.kp-card.locked {
    opacity: 0.7;
    cursor: not-allowed;
}

.kp-status {
    width: 36px;
    height: 36px;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 18px;
    margin-bottom: var(--spacing-md);
}

.kp-card.completed .kp-status {
    background: rgba(129, 199, 132, 0.2);
}

.kp-card.in-progress .kp-status {
    background: rgba(91, 155, 213, 0.2);
}

.kp-card.locked .kp-status {
    background: rgba(168, 155, 145, 0.2);
}

.kp-content h4 {
    font-size: 16px;
    color: var(--text-primary);
    font-weight: 600;
    margin-bottom: var(--spacing-sm);
}

.kp-content p {
    font-size: 13px;
    color: var(--text-secondary);
    line-height: 1.5;
    margin-bottom: var(--spacing-md);
    display: -webkit-box;
    -webkit-line-clamp: 2;
    -webkit-box-orient: vertical;
    overflow: hidden;
}

.kp-meta {
    display: flex;
    align-items: center;
    gap: var(--spacing-md);
    margin-bottom: var(--spacing-md);
}

.difficulty {
    padding: 3px 10px;
    border-radius: 12px;
    font-size: 11px;
    font-weight: 600;
    text-transform: uppercase;
}

.difficulty.easy {
    background: rgba(129, 199, 132, 0.2);
    color: #4CAF50;
}

.difficulty.medium {
    background: rgba(255, 183, 77, 0.2);
    color: #F57C00;
}

.difficulty.hard {
    background: rgba(229, 115, 115, 0.2);
    color: #E53935;
}

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

.btn-review,
.btn-study,
.btn-locked {
    width: 100%;
    padding: 10px;
    border: none;
    border-radius: var(--radius-md);
    font-size: 14px;
    font-weight: 600;
    cursor: pointer;
    transition: all var(--transition-normal);
    font-family: inherit;
}

.btn-review {
    background: rgba(129, 199, 132, 0.15);
    color: #4CAF50;
}

.btn-review:hover {
    background: rgba(129, 199, 132, 0.25);
}

.btn-study {
    background: linear-gradient(135deg, var(--primary-color), var(--primary-dark));
    color: white;
    box-shadow: 0 4px 12px rgba(91, 155, 213, 0.3);
}

.btn-study:hover {
    transform: translateY(-2px);
    box-shadow: 0 6px 20px rgba(91, 155, 213, 0.4);
}

.btn-locked {
    background: var(--bg-tertiary);
    color: var(--text-muted);
    cursor: not-allowed;
}

/* 学习提示卡片 */
.study-tip-card {
    background: linear-gradient(135deg, var(--secondary-light), var(--secondary-color));
    border-radius: var(--radius-lg);
    padding: var(--spacing-lg) var(--spacing-xl);
    display: flex;
    align-items: flex-start;
    gap: var(--spacing-lg);
    box-shadow: var(--shadow-md);
}

.tip-icon {
    font-size: 40px;
    flex-shrink: 0;
}

.tip-content h4 {
    font-size: 16px;
    color: var(--text-primary);
    margin-bottom: var(--spacing-sm);
    font-weight: 600;
}

.tip-content p {
    font-size: 14px;
    line-height: 1.7;
    color: var(--text-secondary);
}

/* 响应式调整 */
@media (max-width: 1024px) {
    .courses-layout {
        grid-template-columns: 1fr;
    }

    .courses-sidebar {
        position: static;
        max-height: 300px;
        overflow-y: auto;
    }

    .knowledge-points {
        grid-template-columns: 1fr;
    }
}

/* ========================================
   课程进度概览卡片 (新增)
   ======================================== */
.course-overview-card {
    background: linear-gradient(135deg, #FFF8F0, #FFF0E5);
    border-radius: var(--radius-xl);
    padding: var(--spacing-lg);
    margin-bottom: var(--spacing-lg);
    cursor: pointer;
    transition: all 0.3s ease;
    border: 2px solid transparent;
}

.course-overview-card:hover {
    border-color: var(--primary-color);
    transform: translateY(-2px);
    box-shadow: 0 4px 20px rgba(255, 120, 80, 0.15);
}

.overview-stats {
    display: flex;
    justify-content: space-around;
    margin-bottom: var(--spacing-md);
}

.stat-item {
    text-align: center;
}

.stat-value {
    display: block;
    font-size: 24px;
    font-weight: 700;
    color: var(--primary-color);
}

.stat-value.points-accent {
    color: #FF9800;
}

.stat-label {
    font-size: 12px;
    color: var(--text-secondary);
    margin-top: 4px;
}

.progress-bar-large {
    height: 12px;
    background: #F0E0D6;
    border-radius: 10px;
    overflow: hidden;
    margin-bottom: var(--spacing-sm);
}

.progress-bar-large .fill {
    height: 100%;
    background: linear-gradient(90deg, #FF9966, #FF6B6B);
    border-radius: 10px;
    transition: width 0.5s ease;
}

.click-hint {
    display: block;
    text-align: center;
    font-size: 12px;
    color: var(--text-secondary);
    opacity: 0.7;
}

/* ========================================
   课程进度详情弹窗 (新增)
   ======================================== */
.course-progress-modal {
    max-width: 520px;
    max-height: 80vh;
    overflow-y: auto;
}

.cpm-header {
    display: flex;
    align-items: center;
    gap: 12px;
    margin-bottom: var(--spacing-lg);
}

.cpm-header h3 { margin: 0; font-size: 18px; }

.grade-tag {
    background: var(--primary-light);
    color: var(--primary-color);
    padding: 3px 10px;
    border-radius: 20px;
    font-size: 12px;
}

.cpm-summary {
    display: flex;
    align-items: center;
    gap: var(--spacing-xl);
    background: linear-gradient(135deg, #FFF5EE, #FFEDE5);
    border-radius: var(--radius-lg);
    padding: var(--spacing-lg);
    margin-bottom: var(--spacing-lg);
}

.cpm-big-progress svg { width: 100px; height: 100px; }

.cpm-stats-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: var(--spacing-sm) var(--spacing-md);
}

.cpm-stat .cpm-num {
    display: block;
    font-size: 22px;
    font-weight: 700;
}
.cpm-stat .cpm-num.success { color: #4CAF50; }
.cpm-stat .cpm-num.warning { color: #FF9800; }
.cpm-stat .cpm-num.muted { color: #999; }
.cpm-stat .cpm-num.points { color: #FF6B6B; font-size: 18px; }
.cpm-stat .cpm-label { font-size: 11px; color: var(--text-secondary); }

.cpm-chapters-section h4,
.cpm-pending-rewards h4 {
    font-size: 15px;
    margin-bottom: var(--spacing-md);
}

.cpm-chapter-row {
    display: flex;
    align-items: center;
    gap: 10px;
    padding: 8px 0;
    border-bottom: 1px dashed #EEE;
}

.cpm-ch-name { width: 140px; font-size: 13px; white-space: nowrap; overflow: hidden; text-overflow: ellipsis; }
.cpm-ch-bar { flex: 1; height: 6px; background: #F0E0D6; border-radius: 3px; }
.cpm-ch-bar .fill { height: 100%; background: linear-gradient(90deg, #FF9966, #FF6B6B); border-radius: 3px; }
.ch-ch-pct { width: 36px; text-align: right; font-size: 12px; font-weight: 600; color: var(--text-secondary); }
.ch-ch-reward { width: 60px; text-align: right; font-size: 12px; color: #FF9800; font-weight: 600; }

.rewards-list { max-height: 240px; overflow-y: auto; }

.reward-item {
    display: flex;
    align-items: center;
    gap: 10px;
    padding: 10px 12px;
    border-radius: var(--radius-md);
    cursor: pointer;
    transition: background 0.2s;
}

.reward-item:hover { background: #FFF5EE; }

.reward-status { font-size: 16px; }
.reward-title { flex: 1; font-size: 14px; }
.reward-chapter { font-size: 11px; color: #999; width: 60px; }
.reward-pts { font-size: 13px; font-weight: 700; color: #FF9800; }

.more-rewards-hint {
    text-align: center;
    font-size: 12px;
    color: #999;
    padding: 10px 0;
}

.all-done-msg {
    text-align: center;
    padding: var(--spacing-xl);
    font-size: 16px;
    color: #4CAF50;
    font-weight: 500;
}

/* ========================================
   知识点视频讲解区域 (新增)
   ======================================== */
.video-section {
    margin-bottom: var(--spacing-lg);
}

.video-player {
    width: 100%;
    border-radius: var(--radius-lg);
    overflow: hidden;
    background: #000;
}

.video-placeholder {
    position: relative;
    width: 100%;
    height: 240px;
    background: linear-gradient(135deg, #1a1a2e, #16213e);
    display: flex;
    align-items: center;
    justify-content: center;
    cursor: pointer;
    overflow: hidden;
}

.video-placeholder.playing {
    cursor: default;
}

.video-placeholder.completed {
    cursor: pointer;
}

.play-button {
    width: 64px;
    height: 64px;
    border-radius: 50%;
    background: rgba(91, 155, 213, 0.9);
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 28px;
    color: white;
    z-index: 3;
    transition: all 0.3s ease;
    box-shadow: 0 4px 20px rgba(0,0,0,0.3);
}

.play-button:hover {
    transform: scale(1.1);
    background: var(--primary-color);
}

.video-info-overlay {
    position: absolute;
    bottom: 16px;
    left: 16px;
    z-index: 2;
    color: white;
}

.video-title {
    font-size: 15px;
    font-weight: 600;
    margin-bottom: 4px;
}

.video-duration {
    font-size: 13px;
    opacity: 0.8;
}

.video-bg-pattern {
    position: absolute;
    top: 0; left: 0; right: 0; bottom: 0;
    background:
        radial-gradient(circle at 20% 30%, rgba(91, 155, 213, 0.15) 0%, transparent 50%),
        radial-gradient(circle at 80% 70%, rgba(107, 196, 216, 0.12) 0%, transparent 50%);
    z-index: 1;
}

.video-placeholder.playing .video-bg-pattern::after {
    content: '';
    position: absolute;
    top: 0; left: -100%; right: 0; bottom: 0;
    background: linear-gradient(90deg, transparent, rgba(255,255,255,0.05), transparent);
    animation: videoShimmer 2s infinite;
}

@keyframes videoShimmer {
    from { left: -100%; }
    to { left: 100%; }
}

/* 视频控制条 */
.video-controls-bar {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 8px 12px;
    background: #f8fafc;
    border-radius: 0 0 var(--radius-md) var(--radius-md);
    font-size: 12px;
    color: var(--text-secondary);
}

.vc-label { font-weight: 600; color: var(--primary-color); }

/* 进度条 */
.video-progress-bar {
    height: 4px;
    background: #e0e0e0;
    border-radius: 2px;
    margin-top: 0;
}

.vp-fill {
    height: 100%;
    background: linear-gradient(90deg, var(--primary-color), #6BC4D8);
    border-radius: 2px;
    transition: width 0.3s linear;
}

.vp-controls {
    display: flex;
    align-items: center;
    gap: 12px;
    padding: 10px 14px;
    background: white;
    border-radius: 0 0 var(--radius-md) var(--radius-md);
    border-top: 1px solid var(--border-color);
}

.vp-btn {
    padding: 5px 12px;
    border-radius: 15px;
    background: var(--bg-tertiary);
    font-size: 12px;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.2s;
    color: var(--text-secondary);
}

.vp-btn:hover {
    background: var(--primary-light);
    color: white;
}

.vp-time {
    font-size: 12px;
    color: var(--text-muted);
    font-family: monospace;
}

.vp-volume {
    cursor: pointer;
    font-size: 16px;
}

/* 详情弹窗增强 */
.kp-detail-modal .kp-detail-header {
    display: flex;
    align-items: center;
    gap: 10px;
    flex-wrap: wrap;
    margin-bottom: var(--spacing-md);
}

.kp-reward-badge {
    margin-left: auto;
    background: linear-gradient(135deg, #FFE082, #FFD54F);
    color: #F57C00;
    padding: 4px 12px;
    border-radius: 12px;
    font-size: 13px;
    font-weight: 700;
}

.kp-detail-body-scrollable {
    max-height: 400px;
    overflow-y: auto;
    padding-right: 8px;
}

.kp-detail-body-scrollable::-webkit-scrollbar {
    width: 6px;
}
.kp-detail-body-scrollable::-webkit-scrollbar-thumb {
    background: #d0d0d0;
    border-radius: 3px;
}

/* 详细内容样式 */
.kp-concepts {
    background: var(--bg-tertiary);
    border-radius: var(--radius-md);
    padding: var(--spacing-md);
    margin: var(--spacing-md) 0;
}

.concept-item {
    padding: 8px 0;
    border-bottom: 1px dashed var(--border-color);
    line-height: 1.7;
    font-size: 14px;
}

.concept-item:last-child {
    border-bottom: none;
}

.study-points {
    list-style: none;
    padding-left: 0 !important;
    margin: var(--spacing-sm) 0;
}

.study-points li {
    position: relative;
    padding: 6px 0 6px 24px;
    font-size: 14px;
    line-height: 1.6;
    color: var(--text-primary);
}

.study-points li::before {
    content: '•';
    position: absolute;
    left: 8px;
    color: var(--primary-color);
    font-weight: bold;
}

.example-box {
    background: linear-gradient(135deg, #E8F5E9, #C8E6C9);
    border-radius: var(--radius-md);
    padding: var(--spacing-md);
    margin: var(--spacing-md) 0;
    font-size: 14px;
    line-height: 1.8;
    border-left: 4px solid #4CAF50;
}

.warning-box {
    background: linear-gradient(135deg, #FFF3E0, #FFE0B2);
    border-radius: var(--radius-md);
    padding: var(--spacing-md);
    margin: var(--spacing-md) 0;
    border-left: 4px solid #F57C00;
    font-size: 14px;
}

.tip-box {
    background: linear-gradient(135deg, #E3F2FD, #BBDEFB);
    border-radius: var(--radius-md);
    padding: var(--spacing-md);
    margin: var(--spacing-md) 0;
    border-left: 4px solid #2196F3;
    font-size: 14px;
    line-height: 1.8;
}

.formula-box {
    background: linear-gradient(135deg, #F3E5F5, #E1BEE7);
    border-radius: var(--radius-md);
    padding: var(--spacing-md);
    margin: var(--spacing-md) 0;
    font-size: 14px;
    line-height: 2;
    text-align: center;
    font-weight: 500;
}

.btn-lg {
    padding: 12px 28px;
    font-size: 16px;
}

.already-done-large {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    padding: 12px 28px;
    background: rgba(76, 175, 80, 0.15);
    color: #4CAF50;
    border-radius: var(--radius-md);
    font-size: 16px;
    font-weight: 700;
}

/* ========================================
   知识点详情 - 学习模块标签页系统
   ======================================== */
.kp-tabs-container {
    margin-top: var(--spacing-lg);
}

.kp-tabs {
    display: flex;
    flex-wrap: wrap;
    gap: 6px;
    padding: 0 var(--spacing-md);
    background: #F5F9FC;
    border-radius: var(--radius-lg) var(--radius-lg) 0 0;
    border-bottom: 2px solid #E8EEF4;
}

.kp-tab {
    padding: 10px 18px;
    background: transparent;
    border: none;
    color: #7A8B99;
    font-size: 14px;
    font-weight: 500;
    cursor: pointer;
    border-radius: var(--radius-md) var(--radius-md) 0 0;
    transition: all 0.25s ease;
    position: relative;
}

.kp-tab:hover {
    color: #5B9BD5;
    background: rgba(91, 155, 213, 0.08);
}

.kp-tab.active {
    color: #fff;
    background: linear-gradient(135deg, #5B9BD5, #6BC4D8);
    box-shadow: 0 3px 12px rgba(91, 155, 213, 0.25);
    transform: translateY(-1px);
}

.kp-tab-panels {
    max-height: 420px;
    overflow-y: auto;
    padding: var(--spacing-lg);
    background: #fff;
    border-radius: 0 0 var(--radius-lg) var(--radius-lg);
    border: 1px solid #E8EEF4;
    border-top: none;
}

.kp-tab-panel {
    display: none;
    animation: fadeInTab 0.3s ease;
}

.kp-tab-panel.active {
    display: block;
}

@keyframes fadeInTab {
    from { opacity: 0; transform: translateY(6px); }
    to { opacity: 1; transform: translateY(0); }
}

.empty-panel {
    text-align: center;
    padding: 40px 20px;
    color: #B0BEC5;
    font-size: 14px;
}

/* === 思维导图样式 === */
.mindmap-container {
    background: linear-gradient(135deg, #F5F9FC, #EDF4FA);
    border-radius: var(--radius-lg);
    padding: var(--spacing-xl);
    text-align: center;
}

.mm-root {
    display: inline-block;
    background: linear-gradient(135deg, #5B9BD5, #6BC4D8);
    color: white;
    padding: 12px 28px;
    border-radius: var(--radius-full);
    font-size: 17px;
    font-weight: 700;
    margin-bottom: var(--spacing-lg);
    box-shadow: 0 4px 15px rgba(91, 155, 213, 0.3);
}

.mm-branch {
    display: flex;
    justify-content: center;
    gap: 15px;
    flex-wrap: wrap;
}

.mm-node {
    background: #fff;
    border: 2px solid #D6E8F5;
    border-radius: var(--radius-md);
    padding: 12px 16px;
    min-width: 140px;
    transition: all 0.25s ease;
    cursor: default;
}

.mm-node:hover {
    border-color: #5B9BD5;
    transform: translateY(-3px);
    box-shadow: 0 6px 20px rgba(91, 155, 213, 0.15);
}

.mm-label {
    display: block;
    font-weight: 600;
    color: #2C3E50;
    margin-bottom: 6px;
    font-size: 14px;
}

.mm-leaves {
    font-size: 12px;
    color: #78909C;
    line-height: 1.6;
}

/* === 课程大纲样式 === */
.syllabus-list {
    counter-reset: syllabus-counter;
    list-style: none;
    padding: 0;
}

.syllabus-list li {
    counter-increment: syllabus-counter;
    position: relative;
    padding: 12px 12px 12px 48px;
    margin-bottom: 10px;
    background: #F8FBFD;
    border-radius: var(--radius-md);
    border-left: 4px solid #5B9BD5;
    line-height: 1.65;
    font-size: 14px;
}

.syllabus-list li::before {
    content: counter(syllabus-counter);
    position: absolute;
    left: 12px;
    top: 12px;
    width: 26px;
    height: 26px;
    background: #5B9BD5;
    color: white;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 13px;
    font-weight: 700;
}

.syllabus-meta {
    margin-top: var(--spacing-md);
    padding: 10px 16px;
    background: linear-gradient(135deg, #FFF8E1, #FFECB3);
    border-radius: var(--radius-md);
    font-size: 13px;
    color: #E65100;
    text-align: center;
    font-weight: 500;
}

/* === 内容详解增强样式 === */
.kp-concepts {
    margin: 12px 0;
}

.concept-item {
    background: #F8FBFD;
    border-left: 3px solid #5B9BD5;
    padding: 10px 14px;
    margin-bottom: 8px;
    border-radius: 0 var(--radius-sm) var(--radius-sm) 0;
    font-size: 14px;
    line-height: 1.7;
}

.study-points {
    padding-left: 20px;
    margin: 10px 0;
}

.study-points li {
    margin-bottom: 6px;
    line-height: 1.65;
    color: #455A64;
}

.example-box {
    background: #FFFDE7;
    border: 1px solid #FFE082;
    border-radius: var(--radius-md);
    padding: 14px;
    margin: 12px 0;
    font-size: 14px;
    line-height: 1.75;
}

.answer-box {
    background: #E8F5E9;
    border-radius: var(--radius-sm);
    padding: 10px 14px;
    margin-top: 10px;
    font-size: 14px;
    line-height: 1.7;
}

.structure-box {
    border: 1px solid #D6E8F5;
    border-radius: var(--radius-md);
    overflow: hidden;
    margin: 12px 0;
}

.struct-part {
    padding: 14px 16px;
    background: #FAFCFF;
    border-bottom: 1px dashed #D6E8F5;
}

.struct-part:last-child { border-bottom: none; }

/* === 重难点解析样式 === */
.difficulty-section h4 {
    color: #2C3E50;
    margin: 16px 0 8px;
    font-size: 15px;
    padding-bottom: 4px;
    border-bottom: 2px solid #5B9BD5;
    display: inline-block;
}

.difficulty-section ul {
    padding-left: 22px;
    margin: 8px 0;
}

.difficulty-section ul li {
    margin-bottom: 5px;
    line-height: 1.65;
    color: #455A64;
}

.warning-box {
    background: linear-gradient(135deg, #FFF3E0, #FFE0B2);
    border: 1px solid #FFCC80;
    border-radius: var(--radius-md);
    padding: 14px;
    margin: 12px 0;
    font-size: 14px;
    line-height: 1.8;
}

.tip-box {
    background: linear-gradient(135deg, #E3F2FD, #BBDEFB);
    border: 1px solid #90CAF9;
    border-radius: var(--radius-md);
    padding: 14px;
    margin: 12px 0;
    font-size: 14px;
    line-height: 1.8;
}

/* === 题库练习样式 === */
.exercise-section .exercise-item {
    background: #FAFCFF;
    border: 1px solid #E8EEF4;
    border-radius: var(--radius-md);
    padding: 16px;
    margin-bottom: 14px;
    transition: all 0.25s ease;
}

.exercise-section .exercise-item:hover {
    border-color: #5B9BD5;
    box-shadow: 0 3px 12px rgba(91, 155, 213, 0.1);
}

.exercise-section h4 {
    color: #2C3E50;
    margin-bottom: 14px;
    padding-bottom: 6px;
    border-bottom: 2px solid #5B9BD5;
}

.options label {
    display: block;
    padding: 6px 0;
    cursor: pointer;
    font-size: 14px;
}

.show-answer-btn {
    margin-top: 10px;
    font-size: 12px !important;
    padding: 4px 14px !important;
}

.answer-hidden {
    margin-top: 10px;
    padding: 12px;
    background: #E8F5E9;
    border-radius: var(--radius-sm);
    font-size: 13px;
    line-height: 1.7;
    border: 1px solid #C8E6C9;
}

.exercise-stats {
    display: flex;
    gap: 16px;
    padding: 10px 14px;
    background: #F5F9FC;
    border-radius: var(--radius-sm);
    font-size: 12px;
    color: #78909C;
    margin-top: 8px;
}