/* 启航数学课堂 - 核心样式表 */

/* 1. 顶部全局导航 */
.site-header {
  background: #FFFFFF;
  border-bottom: 1px solid #EBF1F8;
  position: sticky;
  top: 0;
  z-index: 100;
  box-shadow: 0 2px 10px rgba(30, 96, 255, 0.03);
}

.header-container {
  max-width: 1280px;
  margin: 0 auto;
  padding: 0 24px;
  height: 72px;
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.site-logo {
  display: flex;
  align-items: center;
  gap: 10px;
  font-size: 22px;
  font-weight: 800;
  color: #1A2744;
  letter-spacing: -0.5px;
}

.site-logo svg {
  width: 34px;
  height: 34px;
}

.nav-menu {
  display: flex;
  align-items: center;
  gap: 36px;
  list-style: none;
}

.nav-menu li a {
  font-size: 16px;
  font-weight: 500;
  color: var(--text-secondary);
  padding: 8px 2px;
  position: relative;
}

.nav-menu li a:hover {
  color: var(--primary-color);
}

.nav-menu li.current-menu-item a,
.nav-menu li a.active {
  color: var(--primary-color);
  font-weight: 600;
}

.nav-menu li.current-menu-item a::after,
.nav-menu li a.active::after {
  content: '';
  position: absolute;
  bottom: -2px;
  left: 0;
  width: 100%;
  height: 3px;
  background: var(--primary-color);
  border-radius: 2px;
}

.header-actions {
  display: flex;
  align-items: center;
  gap: 16px;
}

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  font-size: 15px;
  font-weight: 600;
  padding: 9px 24px;
  border-radius: var(--radius-full);
  cursor: pointer;
  border: 1px solid transparent;
  transition: all 0.2s cubic-bezier(0.4, 0, 0.2, 1);
  white-space: nowrap;
}

.btn-outline-primary {
  background: #FFFFFF;
  color: var(--primary-color);
  border-color: var(--primary-color);
}

.btn-outline-primary:hover {
  background: var(--primary-light);
}

.btn-primary {
  background: var(--primary-color);
  color: #FFFFFF;
  box-shadow: 0 4px 14px rgba(30, 96, 255, 0.3);
}

.btn-primary:hover {
  background: var(--primary-hover);
  box-shadow: 0 6px 18px rgba(30, 96, 255, 0.4);
  transform: translateY(-1px);
}

.btn-orange-unlock {
  background: #FFFFFF;
  color: #E65A00;
  border: 1.5px solid #FF8A00;
  width: 100%;
  padding: 13px 20px;
  font-size: 16px;
  border-radius: 12px;
  box-shadow: 0 4px 12px rgba(255, 138, 0, 0.1);
}

.btn-orange-unlock:hover {
  background: var(--accent-orange);
  color: #FFFFFF;
  box-shadow: 0 6px 18px rgba(255, 138, 0, 0.3);
}

/* 2. 首页 Hero 区域 */
.hero-section {
  padding: 40px 0 60px;
  background: linear-gradient(180deg, #F0F6FD 0%, #F8FBFE 100%);
  overflow: hidden;
}

.hero-container {
  max-width: 1280px;
  margin: 0 auto;
  padding: 0 24px;
  display: grid;
  grid-template-columns: 1.05fr 1fr;
  gap: 40px;
  align-items: center;
}

.hero-tag {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  background: #EAF2FF;
  color: var(--primary-color);
  font-size: 14px;
  font-weight: 600;
  padding: 6px 16px;
  border-radius: var(--radius-full);
  margin-bottom: 20px;
}

.hero-title {
  font-size: 42px;
  font-weight: 800;
  line-height: 1.25;
  color: #152238;
  margin-bottom: 16px;
  letter-spacing: -0.5px;
}

.hero-subtitle {
  font-size: 17px;
  color: var(--text-secondary);
  margin-bottom: 32px;
  display: flex;
  align-items: center;
  gap: 12px;
  flex-wrap: wrap;
}

.hero-subtitle span.dot {
  color: #CBD5E1;
  font-size: 12px;
}

.hero-cta-group {
  margin-bottom: 36px;
}

.hero-cta-group .btn {
  padding: 12px 36px;
  font-size: 16px;
}

.hero-features-bar {
  display: flex;
  align-items: center;
  gap: 16px;
  flex-wrap: wrap;
}

.feature-pill {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  background: #FFFFFF;
  border: 1px solid #DCE6F5;
  border-radius: var(--radius-full);
  padding: 8px 18px;
  font-size: 14px;
  font-weight: 600;
  color: #2D3D58;
  box-shadow: 0 2px 6px rgba(30, 96, 255, 0.04);
}

.feature-pill-icon {
  width: 24px;
  height: 24px;
  border-radius: 50%;
  background: var(--primary-light);
  color: var(--primary-color);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 12px;
}

/* 首页 Banner 右侧 3D 老师与黑板展示 */
.hero-visual-card {
  position: relative;
  background: #203A68;
  border-radius: var(--radius-xl);
  padding: 24px;
  color: #FFFFFF;
  box-shadow: 0 20px 48px rgba(18, 42, 85, 0.22);
  border: 6px solid #B0C4DE;
  min-height: 340px;
  display: flex;
  flex-direction: column;
  justify-content: space-between;
}

.board-content {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 20px;
  align-items: center;
}

.board-formula-box {
  background: rgba(255, 255, 255, 0.08);
  border-radius: 12px;
  padding: 16px;
  font-family: 'Cambria Math', 'Times New Roman', serif;
  font-size: 15px;
  line-height: 1.8;
}

.board-formula-box .triangle-svg {
  width: 100%;
  height: 100px;
  margin-bottom: 8px;
}

.board-teacher-side {
  position: relative;
  text-align: center;
}

.teacher-avatar-3d {
  width: 170px;
  margin: 0 auto;
  filter: drop-shadow(0 12px 20px rgba(0, 0, 0, 0.3));
}

.floating-math-badges {
  position: absolute;
  right: -24px;
  top: 10px;
  display: flex;
  flex-direction: column;
  gap: 10px;
}

.f-badge {
  background: rgba(255, 255, 255, 0.95);
  color: #1E60FF;
  font-weight: 700;
  padding: 6px 14px;
  border-radius: 10px;
  font-size: 13px;
  box-shadow: 0 6px 16px rgba(0, 0, 0, 0.15);
  backdrop-filter: blur(8px);
}

.f-badge.orange {
  background: #FF8A00;
  color: #FFFFFF;
}

.board-toolbar {
  display: flex;
  align-items: center;
  gap: 12px;
  background: rgba(255, 255, 255, 0.12);
  padding: 8px 16px;
  border-radius: var(--radius-full);
  width: fit-content;
  margin-top: 16px;
}

/* 3. 课程列表区域 */
.section-title-wrap {
  text-align: center;
  margin-bottom: 40px;
}

.section-diamond-title {
  display: inline-flex;
  align-items: center;
  gap: 12px;
  font-size: 24px;
  font-weight: 800;
  color: #1A2845;
}

.section-diamond-title::before,
.section-diamond-title::after {
  content: '◆';
  color: #A3C2F7;
  font-size: 14px;
}

.courses-grid-section {
  padding: 60px 0;
}

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

.courses-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 28px;
}

.course-card {
  background: #FFFFFF;
  border-radius: var(--radius-lg);
  padding: 24px;
  box-shadow: var(--shadow-sm);
  border: 1px solid #EBF1F8;
  display: flex;
  gap: 20px;
  transition: transform 0.25s ease, box-shadow 0.25s ease;
  position: relative;
  overflow: hidden;
}

.course-card:hover {
  transform: translateY(-4px);
  box-shadow: var(--shadow-md);
  border-color: #D3E2FA;
}

.course-card-thumb {
  width: 100px;
  height: 100px;
  border-radius: 12px;
  background: #F0F6FF;
  flex-shrink: 0;
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 12px;
}

.course-card-body {
  flex: 1;
  display: flex;
  flex-direction: column;
  justify-content: space-between;
}

.course-card-title {
  font-size: 19px;
  font-weight: 700;
  color: #1B2942;
  margin-bottom: 6px;
}

.course-card-meta {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  font-size: 13px;
  color: var(--primary-color);
  background: var(--primary-light);
  padding: 3px 10px;
  border-radius: 6px;
  font-weight: 600;
  width: fit-content;
  margin-bottom: 12px;
}

.course-progress-bar-wrap {
  margin-bottom: 14px;
}

.course-progress-track {
  height: 6px;
  background: #EDF2F7;
  border-radius: 3px;
  overflow: hidden;
  margin-bottom: 6px;
}

.course-progress-fill {
  height: 100%;
  background: var(--primary-color);
  border-radius: 3px;
}

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

.course-card-action {
  align-self: flex-start;
}

.course-card-action .btn {
  padding: 6px 18px;
  font-size: 13px;
}

/* 4. 为什么学生愿意坚持学 - 特色卡片 */
.value-prop-section {
  padding: 40px 0 80px;
}

.value-prop-box {
  background: #FFFFFF;
  border-radius: var(--radius-xl);
  padding: 36px 40px;
  box-shadow: var(--shadow-sm);
  border: 1px solid #EBF1F8;
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 28px;
}

.value-prop-item {
  display: flex;
  align-items: flex-start;
  gap: 16px;
}

.vp-icon-circle {
  width: 48px;
  height: 48px;
  border-radius: 50%;
  background: #EBF3FF;
  color: var(--primary-color);
  flex-shrink: 0;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 20px;
}

.vp-icon-circle.orange { background: #FFF4E5; color: #FF8A00; }
.vp-icon-circle.green { background: #E8FAF1; color: #20C073; }
.vp-icon-circle.purple { background: #F3E8FF; color: #9333EA; }

.vp-content h4 {
  font-size: 16px;
  font-weight: 700;
  color: #1D2A44;
  margin-bottom: 6px;
}

.vp-content p {
  font-size: 13px;
  color: var(--text-secondary);
  line-height: 1.6;
}

/* 5. 播放页 (Single Lesson) 布局 */
.player-page-container {
  max-width: 1320px;
  margin: 0 auto;
  padding: 24px 24px 60px;
}

.breadcrumb-nav {
  display: flex;
  align-items: center;
  gap: 8px;
  font-size: 14px;
  color: var(--primary-color);
  margin-bottom: 20px;
  font-weight: 500;
}

.breadcrumb-nav span.separator {
  color: #A0AEC0;
}

.player-layout-grid {
  display: grid;
  grid-template-columns: 1fr 380px;
  gap: 28px;
  align-items: start;
}

/* 视频播放器外框 */
.video-player-card {
  background: #0E182A;
  border-radius: var(--radius-lg);
  overflow: hidden;
  box-shadow: var(--shadow-lg);
  position: relative;
}

.video-header-bar {
  padding: 14px 20px;
  background: rgba(14, 24, 42, 0.95);
  color: #FFFFFF;
  font-size: 17px;
  font-weight: 700;
  border-bottom: 1px solid rgba(255, 255, 255, 0.08);
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.video-screen-wrapper {
  position: relative;
  width: 100%;
  padding-top: 56.25%; /* 16:9 比例 */
  background: #111D33;
}

.video-element,
.hls-video-player {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  object-fit: contain;
}

/* 动态防录屏浮动水印 */
.player-watermark-canvas {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  pointer-events: none;
  z-index: 15;
}

/* 自定义播放器控制条 */
.custom-player-controls {
  position: absolute;
  bottom: 0;
  left: 0;
  width: 100%;
  padding: 12px 18px;
  background: linear-gradient(180deg, transparent 0%, rgba(10, 18, 32, 0.95) 100%);
  display: flex;
  align-items: center;
  gap: 14px;
  z-index: 20;
  color: #FFFFFF;
}

.ctl-btn {
  background: none;
  border: none;
  color: #FFFFFF;
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 16px;
  padding: 4px;
  border-radius: 4px;
  transition: transform 0.15s;
}

.ctl-btn:hover {
  color: var(--primary-light);
  transform: scale(1.1);
}

.time-display {
  font-size: 13px;
  font-family: monospace;
  color: #CBD5E1;
}

.progress-slider-wrap {
  flex: 1;
  height: 6px;
  background: rgba(255, 255, 255, 0.2);
  border-radius: 3px;
  position: relative;
  cursor: pointer;
}

.progress-slider-fill {
  position: absolute;
  top: 0;
  left: 0;
  height: 100%;
  background: var(--primary-color);
  border-radius: 3px;
  width: 51.2%; /* 演示 08:32 / 16:40 */
}

.speed-select-btn {
  background: rgba(255, 255, 255, 0.15);
  border: 1px solid rgba(255, 255, 255, 0.25);
  color: #FFFFFF;
  padding: 3px 10px;
  border-radius: 6px;
  font-size: 13px;
  cursor: pointer;
}

.quality-badge-btn {
  background: rgba(255, 255, 255, 0.15);
  border: 1px solid rgba(255, 255, 255, 0.25);
  color: #FFFFFF;
  padding: 3px 10px;
  border-radius: 6px;
  font-size: 13px;
}

/* 进度保存提示 */
.progress-save-notice {
  display: flex;
  align-items: center;
  gap: 8px;
  color: var(--primary-color);
  font-size: 14px;
  font-weight: 500;
  margin: 16px 0 20px;
}

/* 讲义与笔记选项卡 */
.lesson-tabs-card {
  background: #FFFFFF;
  border-radius: var(--radius-lg);
  padding: 24px;
  box-shadow: var(--shadow-sm);
  border: 1px solid #EBF1F8;
}

.tabs-header-nav {
  display: flex;
  align-items: center;
  gap: 32px;
  border-bottom: 1px solid #EAEFF6;
  padding-bottom: 14px;
  margin-bottom: 20px;
}

.tab-nav-btn {
  background: none;
  border: none;
  font-size: 16px;
  font-weight: 600;
  color: var(--text-secondary);
  cursor: pointer;
  padding-bottom: 6px;
  position: relative;
  display: flex;
  align-items: center;
  gap: 8px;
}

.tab-nav-btn.active {
  color: var(--primary-color);
}

.tab-nav-btn.active::after {
  content: '';
  position: absolute;
  bottom: -15px;
  left: 0;
  width: 100%;
  height: 3px;
  background: var(--primary-color);
  border-radius: 2px;
}

.tab-content-panel {
  display: flex;
  justify-content: space-between;
  align-items: flex-start;
  gap: 24px;
}

.handout-list {
  list-style-type: decimal;
  padding-left: 20px;
  color: #2D3748;
  font-size: 14px;
  line-height: 2;
  flex: 1;
}

.download-pdf-btn {
  background: #FFFFFF;
  color: var(--primary-color);
  border: 1.5px solid var(--primary-color);
  padding: 8px 18px;
  border-radius: 10px;
  font-weight: 600;
  font-size: 14px;
  display: inline-flex;
  align-items: center;
  gap: 8px;
  flex-shrink: 0;
}

.download-pdf-btn:hover {
  background: var(--primary-light);
}

/* 6. 右侧章节目录与解锁侧边栏 */
.playlist-sidebar-card {
  background: #FFFFFF;
  border-radius: var(--radius-lg);
  padding: 24px;
  box-shadow: var(--shadow-sm);
  border: 1px solid #EBF1F8;
  position: sticky;
  top: 96px;
}

.sidebar-chapter-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: 20px;
  padding-bottom: 16px;
  border-bottom: 1px solid #EDF2F7;
}

.sidebar-chapter-title {
  font-size: 20px;
  font-weight: 800;
  color: #17253D;
}

.chapter-progress-ring-badge {
  display: flex;
  align-items: center;
  gap: 8px;
  font-size: 13px;
  color: var(--text-secondary);
}

.ring-text strong {
  color: #17253D;
  font-size: 16px;
}

.playlist-items-list {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: 8px;
  margin-bottom: 24px;
}

.playlist-item-row {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 12px 14px;
  border-radius: 12px;
  border: 1px solid transparent;
  transition: all 0.2s ease;
  cursor: pointer;
  background: #F8FAFD;
}

.playlist-item-row:hover {
  background: #F0F5FF;
  border-color: #D6E4FF;
}

.playlist-item-row.active {
  background: #EBF3FF;
  border-color: #BBD5FF;
}

.pi-left {
  display: flex;
  align-items: center;
  gap: 12px;
  font-size: 14px;
  font-weight: 600;
  color: #2D3748;
}

.pi-icon-circle {
  width: 26px;
  height: 26px;
  border-radius: 50%;
  background: #E2E8F0;
  color: #718096;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 11px;
}

.playlist-item-row.active .pi-icon-circle {
  background: var(--primary-color);
  color: #FFFFFF;
}

.pi-right {
  display: flex;
  align-items: center;
  gap: 8px;
}

.status-badge-learning {
  font-size: 12px;
  color: var(--primary-color);
  font-weight: 600;
}

.status-badge-vip {
  font-size: 11px;
  color: #E65A00;
  background: #FFF0E0;
  padding: 2px 8px;
  border-radius: 6px;
  font-weight: 600;
}

.lock-icon-svg {
  color: #A0AEC0;
  width: 16px;
  height: 16px;
}

/* 7. 页脚 */
.site-footer {
  background: #FFFFFF;
  border-top: 1px solid #EBF1F8;
  padding: 40px 0;
  text-align: center;
  color: var(--text-muted);
  font-size: 14px;
}

.site-footer p {
  margin-bottom: 8px;
}

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

@media (max-width: 640px) {
  .value-prop-box {
    grid-template-columns: 1fr;
  }
  .header-container {
    padding: 0 16px;
  }
  .nav-menu {
    display: none; /* 移动端抽屉导航 */
  }
}