/* ============================================
   L-MATH 乐学数学 - 年级列表页共享样式
   用于 grades/gradeX/index.html 和 index2.html
   ============================================ */

/* 页面背景 */
body {
  background: #FFFBF5;
}

/* 年级头部 */
.grade-header {
  color: white;
  padding: 48px 24px 64px;
  text-align: center;
}

.grade-header .grade-emoji {
  font-size: 3rem;
  margin-bottom: 12px;
}

.grade-header h1 {
  font-family: 'ZCOOL KuaiLe', cursive;
  font-size: 2rem;
  margin-bottom: 8px;
}

.grade-header p {
  opacity: 0.9;
  font-size: 1rem;
}

.grade-header .grade-badge {
  display: inline-block;
  background: rgba(255,255,255,0.25);
  padding: 4px 16px;
  border-radius: 999px;
  font-size: 0.85rem;
  margin-top: 12px;
}

/* 年级主体 */
.grade-body {
  padding: 32px 24px;
  max-width: 900px;
  margin: 0 auto;
}

/* 单元卡片 */
.unit-card {
  background: white;
  border-radius: 16px;
  padding: 20px 24px;
  margin-bottom: 16px;
  display: flex;
  align-items: center;
  gap: 16px;
  box-shadow: 0 2px 8px rgba(0,0,0,0.06);
  border: 1px solid #f0f0f0;
  transition: all 0.3s;
  text-decoration: none;
  color: inherit;
}

.unit-card:hover {
  transform: translateY(-2px);
  box-shadow: 0 6px 20px rgba(0,0,0,0.1);
}

.unit-num {
  width: 44px;
  height: 44px;
  border-radius: 12px;
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: 800;
  font-size: 1.1rem;
  color: white;
  flex-shrink: 0;
}

.unit-info {
  flex: 1;
}

.unit-info h3 {
  font-size: 1.1rem;
  color: #2D3436;
  margin-bottom: 4px;
}

.unit-info p {
  font-size: 0.85rem;
  color: #888;
}

.unit-title {
  font-weight: 700;
  font-size: 1.05rem;
  color: #333;
  margin-bottom: 4px;
}

.unit-desc {
  font-size: 0.85rem;
  color: #888;
}

.unit-arrow {
  color: #ccc;
  font-size: 1.2rem;
}

/* 返回链接 */
.back-link {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  color: #666;
  font-size: 0.9rem;
  margin-bottom: 20px;
  text-decoration: none;
}

.back-link:hover {
  color: #FF6B6B;
}

/* 学期切换标签 */
.semester-tabs {
  display: flex;
  gap: 12px;
  justify-content: center;
  margin-bottom: 24px;
}

.semester-tab {
  padding: 10px 24px;
  border-radius: 999px;
  font-weight: 600;
  font-size: 0.95rem;
  background: white;
  color: #666;
  border: 2px solid #eee;
  cursor: pointer;
  transition: all 0.3s;
  text-decoration: none;
}

.semester-tab.active {
  background: #FF6B6B;
  color: white;
  border-color: #FF6B6B;
}

.semester-tab:hover:not(.active) {
  border-color: #FF6B6B;
  color: #FF6B6B;
}

/* 面包屑导航 */
.breadcrumb {
  background: white;
  padding: 16px 24px;
  border-radius: 12px;
  margin-bottom: 24px;
  box-shadow: 0 2px 8px rgba(0,0,0,0.06);
}

.breadcrumb-list {
  display: flex;
  align-items: center;
  gap: 8px;
  list-style: none;
  flex-wrap: wrap;
}

.breadcrumb-item a {
  color: #FF6B6B;
  text-decoration: none;
}

.breadcrumb-item a:hover {
  text-decoration: underline;
}

.breadcrumb-item span {
  color: #888;
}

.breadcrumb-separator {
  color: #ccc;
}