/**
 * common.css - Practice 模块通用样式
 * 可被各学科 practice.html 覆盖
 */

/* ===== 通用容器 ===== */
.practice-container {
  max-width: 860px;
  margin: 0 auto;
  padding: 24px 16px 48px;
  background: #ffffff;
  color: #111111;
  line-height: 1.7;
  font-size: 15px;
  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
}

/* ===== 导航 ===== */
.practice-nav {
  padding-bottom: 12px;
  margin-bottom: 20px;
  border-bottom: 1px solid #e0e0e0;
  font-size: 0.88rem;
  color: #888888;
}

.practice-nav a {
  color: #111111;
  text-decoration: none;
  border-bottom: 1px solid #cccccc;
}

.practice-nav a:hover {
  border-bottom-color: #111111;
}

.practice-nav .sep {
  color: #cccccc;
  margin: 0 6px;
}

/* ===== 标题 ===== */
.practice-container h1 {
  font-size: 1.6rem;
  margin-bottom: 4px;
}

.practice-container h2 {
  font-size: 1.1rem;
  font-weight: 700;
  margin: 28px 0 8px;
  padding-bottom: 6px;
  border-bottom: 1px solid #111111;
}

.practice-container h3 {
  font-size: 1rem;
  font-weight: 700;
  margin: 18px 0 6px;
}

/* ===== 卡片 ===== */
.practice-card {
  border: 1px solid #e0e0e0;
  padding: 14px 16px;
  background: #ffffff;
  margin: 12px 0;
}

.practice-card h3 {
  margin-top: 0;
}

/* ===== 网格 ===== */
.practice-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 16px;
  margin: 16px 0;
}

.practice-grid-3 {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 16px;
  margin: 16px 0;
}

@media (max-width: 768px) {
  .practice-grid,
  .practice-grid-3 {
    grid-template-columns: 1fr;
  }
}

@media (min-width: 769px) and (max-width: 1024px) {
  .practice-grid-3 {
    grid-template-columns: 1fr 1fr;
  }
}

/* ===== 表格 ===== */
.practice-container table {
  width: 100%;
  border-collapse: collapse;
  font-size: 0.82rem;
  margin: 8px 0 16px;
}

.practice-container th,
.practice-container td {
  border: 1px solid #e0e0e0;
  padding: 6px 10px;
  text-align: left;
  vertical-align: top;
}

.practice-container th {
  background: #ffffff;
  border-bottom: 2px solid #111111;
  font-weight: 700;
}

/* ===== 徽章 ===== */
.practice-badge {
  display: inline-block;
  border: 1px solid #111111;
  padding: 0 6px;
  font-size: 0.7rem;
  font-weight: 700;
}

.practice-badge-dashed {
  border-style: dashed;
  color: #888888;
}

/* ===== 统计数字 ===== */
.practice-stats {
  display: grid;
  grid-template-columns: repeat(5, 1fr);
  gap: 10px;
  margin: 14px 0;
}

@media (max-width: 768px) {
  .practice-stats {
    grid-template-columns: repeat(2, 1fr);
  }
}

.practice-stat {
  border: 1px solid #e0e0e0;
  padding: 12px 10px;
  text-align: center;
  background: #ffffff;
}

.practice-stat .stat-value {
  font-size: 1.3rem;
  font-weight: 700;
  color: #111111;
}

.practice-stat .stat-label {
  font-size: 0.72rem;
  color: #888888;
  margin-top: 4px;
}

/* ===== 信息框 ===== */
.practice-v-info {
  border: 1px dashed #888888;
  padding: 8px 12px;
  margin: 12px 0;
  font-size: 0.82rem;
  color: #555555;
}

/* ===== 底部 ===== */
.practice-footer {
  margin-top: 36px;
  padding-top: 16px;
  border-top: 1px solid #e0e0e0;
  color: #888888;
  font-size: 0.82rem;
}

/* ===== 链接 ===== */
.practice-container a {
  color: #111111;
  text-decoration: none;
  border-bottom: 1px solid #cccccc;
}

.practice-container a:hover {
  border-bottom-color: #111111;
}

/* ===== 做题样式 ===== */
.practice-q {
  border: 1px solid #e0e0e0;
  padding: 14px 16px;
  margin: 14px 0;
  background: #fafafa;
}

.practice-q-num {
  font-weight: 700;
  font-size: 0.85rem;
  color: #555555;
  margin-bottom: 6px;
}

.practice-q-stem {
  margin-bottom: 10px;
}

.practice-q-choices {
  list-style: none;
  padding: 0;
  margin: 0;
}

.practice-q-choices li {
  padding: 6px 12px;
  cursor: pointer;
  border: 1px solid #e0e0e0;
  margin-bottom: 4px;
  background: #fff;
  font-size: 0.88rem;
}

.practice-q-choices li:hover {
  background: #f5f5f5;
}

.practice-q-choices li.correct {
  border-left: 3px solid #111;
  font-weight: 700;
  padding-left: 9px;
}

.practice-q-choices li.wrong {
  border-left: 3px dashed #888;
  padding-left: 9px;
}

.practice-q-answer {
  margin-top: 10px;
  padding: 10px;
  background: #f5f5f5;
  border: 1px solid #e0e0e0;
  font-size: 0.85rem;
}

/* ===== 按钮 ===== */
.practice-btn {
  border: 1px solid #111111;
  background: #fff;
  color: #111111;
  padding: 6px 14px;
  cursor: pointer;
  font-weight: 600;
  font-family: inherit;
  font-size: 0.9rem;
}

.practice-btn:hover {
  background: #111111;
  color: #fff;
}

/* ===== 懒加载图片 ===== */
img[loading="lazy"] {
  background: #f0f0f0;
  min-height: 100px;
}

/* ===== 字体预加载备用 ===== */
@font-face {
  font-family: 'system-fallback';
  src: local(-apple-system), local(BlinkMacSystemFont), local('Segoe UI'), local(Roboto), local(sans-serif);
}

/* ===== 暗色模式 ===== */
@media (prefers-color-scheme: dark) {
  .practice-container {
    background: #111;
    color: #e5e5e5;
  }
  .practice-container a {
    color: #e5e5e5;
    border-color: #555;
  }
  .practice-card,
  .practice-stat,
  .practice-q {
    background: #1a1a1a;
    border-color: #444;
  }
  .practice-container th {
    background: #1a1a1a;
  }
  .practice-container th,
  .practice-container td {
    border-color: #444;
  }
  .practice-q-choices li {
    background: #222;
    border-color: #444;
    color: #e5e5e5;
  }
  .practice-q-choices li:hover {
    background: #2a2a2a;
  }
  .practice-q-answer {
    background: #1a1a1a;
    border-color: #444;
  }
  .practice-btn {
    background: #1a1a1a;
    color: #e5e5e5;
    border-color: #555;
  }
  .practice-btn:hover {
    background: #333;
  }
}