/* ============================================================
   课程浏览器样式
   ============================================================ */

.course-header {
  margin-bottom: 14px;
}
.course-header h2 {
  font-size: 18px;
  font-weight: 700;
  margin-bottom: 4px;
}
.course-header__stats {
  font-size: 13px;
  color: var(--tg-hint);
}

.course-level-tabs {
  margin-bottom: 16px;
}

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

.course-card {
  display: flex;
  align-items: center;
  gap: 12px;
  background: var(--tg-secondary-bg);
  border-radius: var(--radius);
  padding: 14px;
  box-shadow: var(--shadow);
  cursor: pointer;
  transition: opacity 0.15s;
}
.course-card:active {
  opacity: 0.7;
}
.course-card--done {
  border-left: 3px solid #34c759;
}
.course-card--current {
  border-left: 3px solid var(--tg-button);
}
.course-card--pending {
  border-left: 3px solid var(--tg-hint);
  opacity: 0.6;
}
.course-card__icon {
  font-size: 28px;
  flex-shrink: 0;
}
.course-card__info {
  flex: 1;
  min-width: 0;
}
.course-card__topic {
  font-weight: 600;
  font-size: 15px;
  margin-bottom: 4px;
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}
.course-card__meta {
  display: flex;
  align-items: center;
  gap: 8px;
}
.course-card__date {
  font-size: 11px;
  color: var(--tg-hint);
}
.course-start-btn {
  flex-shrink: 0;
}

/* ============================================================
   课程学习页面 (course-lesson) 样式
   ============================================================ */

/* 课程头部：标题 + 音频按钮 */
.lesson-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 8px;
  margin-bottom: 12px;
  flex-wrap: wrap;
}
.lesson-header__info {
  display: flex;
  align-items: center;
  gap: 8px;
  flex: 1;
  min-width: 0;
}
.lesson-header__info h2 {
  font-size: 17px;
  font-weight: 700;
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}

/* 音频播放按钮 */
.lesson-audio-btn {
  display: flex;
  align-items: center;
  gap: 4px;
  padding: 8px 14px;
  border: 1px solid var(--tg-button);
  border-radius: 20px;
  background: var(--tg-secondary-bg);
  color: var(--tg-button);
  font-size: 13px;
  font-weight: 500;
  cursor: pointer;
  flex-shrink: 0;
  transition: all 0.15s;
}
.lesson-audio-btn:active {
  background: var(--tg-button);
  color: var(--tg-button-text);
}
.lesson-audio-btn--loading {
  opacity: 0.6;
  pointer-events: none;
}

/* 课程内容卡片 */
.lesson-content {
  font-size: 14px;
  line-height: 1.7;
}

/* 课程内联对话 */
.lesson-chat-section {
  margin-top: 12px;
  border: 1px solid var(--tg-secondary-bg);
  border-radius: var(--radius);
  overflow: hidden;
}
.lesson-chat-header {
  padding: 10px 14px;
  font-size: 14px;
  font-weight: 600;
  background: var(--tg-secondary-bg);
  border-bottom: 1px solid var(--tg-bg);
}

/* 聊天消息区 */
.lesson-chat-messages {
  height: 220px;
  overflow-y: auto;
  padding: 10px 12px;
  display: flex;
  flex-direction: column;
  gap: 8px;
  background: var(--tg-bg);
  -webkit-overflow-scrolling: touch;
}

/* 聊天欢迎提示 */
.lesson-chat-welcome {
  text-align: center;
  padding: 16px 10px;
  color: var(--tg-hint);
  font-size: 13px;
  line-height: 1.6;
}

/* 聊天输入栏 */
.lesson-chat-input-bar {
  display: flex;
  gap: 6px;
  padding: 8px 10px;
  background: var(--tg-secondary-bg);
  border-top: 1px solid var(--tg-bg);
}
.lesson-chat-input-bar input {
  flex: 1;
  height: 36px;
  padding: 0 12px;
  border: 1px solid var(--tg-secondary-bg);
  border-radius: 18px;
  font-size: 14px;
  background: var(--tg-bg);
  color: var(--tg-text);
  outline: none;
}
.lesson-chat-input-bar input:focus {
  border-color: var(--tg-button);
}
.lesson-chat-input-bar button {
  width: 36px; height: 36px;
  border-radius: 50%;
  border: none;
  background: var(--tg-button);
  color: var(--tg-button-text);
  font-size: 16px;
  cursor: pointer;
  flex-shrink: 0;
  display: flex;
  align-items: center;
  justify-content: center;
}
.lesson-chat-input-bar button:disabled {
  opacity: 0.5;
}

/* 加载状态 */
.lesson-loading {
  text-align: center;
  padding: 40px 20px;
}

/* ============================================================
   进度条 & 检查点
   ============================================================ */

.course-progress-bar {
  height: 4px;
  background: var(--tg-secondary-bg);
  border-radius: 2px;
  overflow: hidden;
  margin-top: 4px;
}
.course-progress-fill {
  height: 100%;
  background: var(--tg-button);
  border-radius: 2px;
  transition: width 0.3s ease;
}
.course-progress-fill--done {
  background: #34c759;
}

/* 检查点指示器 */
.lesson-checkpoints {
  display: flex;
  gap: 8px;
  margin-bottom: 12px;
  flex-wrap: wrap;
}
.lesson-cp {
  font-size: 12px;
  padding: 3px 8px;
  border-radius: 10px;
  background: var(--tg-secondary-bg);
  color: var(--tg-hint);
  white-space: nowrap;
}
.lesson-cp--done {
  background: #34c759;
  color: #fff;
}