/* 英语课本教学网站 - 样式 */
:root {
  --primary: #2563eb;
  --primary-dark: #1e40af;
  --primary-light: #dbeafe;
  --success: #16a34a;
  --success-light: #dcfce7;
  --danger: #dc2626;
  --danger-light: #fee2e2;
  --warning: #d97706;
  --warning-light: #fef3c7;
  --bg: #f1f5f9;
  --card: #ffffff;
  --text: #1e293b;
  --text-light: #64748b;
  --border: #e2e8f0;
  --radius: 12px;
}

* { margin: 0; padding: 0; box-sizing: border-box; }

body {
  font-family: "PingFang SC", "Microsoft YaHei", "Noto Sans CJK SC", sans-serif;
  background: var(--bg);
  color: var(--text);
  line-height: 1.6;
  padding-bottom: 60px;
}

/* 顶部导航 */
.topbar {
  background: var(--primary);
  color: #fff;
  padding: 14px 20px;
  display: flex;
  align-items: center;
  gap: 12px;
  position: sticky;
  top: 0;
  z-index: 100;
  box-shadow: 0 2px 8px rgba(0,0,0,.15);
}
.topbar .logo { font-weight: 700; font-size: 18px; cursor: pointer; white-space: nowrap; }
.topbar .crumb { font-size: 14px; opacity: .9; white-space: nowrap; overflow: hidden; text-overflow: ellipsis; }
.topbar .back { cursor: pointer; font-size: 20px; padding: 0 4px; user-select: none; }

.container { max-width: 900px; margin: 0 auto; padding: 20px 16px; }

h1.page-title { font-size: 24px; margin-bottom: 6px; }
p.subtitle { color: var(--text-light); margin-bottom: 20px; font-size: 14px; }

/* 卡片 */
.card {
  background: var(--card);
  border-radius: var(--radius);
  padding: 20px;
  margin-bottom: 16px;
  box-shadow: 0 1px 3px rgba(0,0,0,.08);
  border: 1px solid var(--border);
}

/* 选择步骤 */
.step-label { font-size: 14px; font-weight: 600; color: var(--text-light); margin: 16px 0 8px; }
.step-label:first-child { margin-top: 0; }

.chip-row { display: flex; flex-wrap: wrap; gap: 10px; }
.chip {
  padding: 10px 18px;
  border-radius: 999px;
  border: 2px solid var(--border);
  background: #fff;
  cursor: pointer;
  font-size: 15px;
  transition: all .15s;
  user-select: none;
}
.chip:hover { border-color: var(--primary); color: var(--primary); }
.chip.active { background: var(--primary); border-color: var(--primary); color: #fff; }

/* 按钮 */
.btn {
  display: inline-block;
  padding: 10px 22px;
  border-radius: 8px;
  border: none;
  font-size: 15px;
  cursor: pointer;
  transition: all .15s;
  text-decoration: none;
  text-align: center;
}
.btn-primary { background: var(--primary); color: #fff; }
.btn-primary:hover { background: var(--primary-dark); }
.btn-success { background: var(--success); color: #fff; }
.btn-success:hover { filter: brightness(1.1); }
.btn-outline { background: #fff; color: var(--primary); border: 2px solid var(--primary); }
.btn-outline:hover { background: var(--primary-light); }
.btn:disabled { opacity: .5; cursor: not-allowed; }
.btn-block { display: block; width: 100%; }

/* 单元列表 */
.unit-list { list-style: none; }
.unit-item {
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 16px 18px;
  margin-bottom: 12px;
  cursor: pointer;
  transition: all .15s;
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 12px;
}
.unit-item:hover { border-color: var(--primary); box-shadow: 0 2px 8px rgba(37,99,235,.12); }
.unit-item .u-title { font-weight: 600; font-size: 17px; }
.unit-item .u-topic { color: var(--text-light); font-size: 13px; margin-top: 2px; }
.unit-item .u-arrow { color: var(--primary); font-size: 20px; }

/* 单元内 tab */
.tabs { display: flex; gap: 8px; margin-bottom: 20px; flex-wrap: wrap; }
.tab {
  padding: 9px 18px;
  border-radius: 8px;
  border: 2px solid var(--border);
  background: #fff;
  cursor: pointer;
  font-size: 14px;
  font-weight: 500;
}
.tab.active { background: var(--primary); border-color: var(--primary); color: #fff; }

/* 单词卡片 */
.word-grid { display: grid; grid-template-columns: repeat(auto-fill, minmax(240px, 1fr)); gap: 14px; }
.word-card {
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 16px;
  cursor: pointer;
  transition: all .2s;
  position: relative;
}
.word-card:hover { transform: translateY(-2px); box-shadow: 0 4px 12px rgba(0,0,0,.1); }
.word-card.flipped { background: var(--primary-light); border-color: var(--primary); }
.word-card .en { font-size: 20px; font-weight: 700; color: var(--primary); }
.word-card .ph { color: var(--text-light); font-size: 13px; }
.word-card .zh { font-size: 16px; margin-top: 6px; color: var(--text); }
.word-card .hint { position: absolute; top: 8px; right: 10px; font-size: 12px; color: var(--text-light); }

/* 句型 */
.sentence-item {
  padding: 12px 16px;
  border-left: 4px solid var(--primary);
  background: var(--primary-light);
  border-radius: 0 8px 8px 0;
  margin-bottom: 10px;
}
.sentence-item .sen-en { font-size: 17px; font-weight: 600; }
.sentence-item .sen-zh { color: var(--text-light); font-size: 14px; }

/* 语法 */
.grammar-box { background: var(--warning-light); border: 1px solid #fcd34d; border-radius: var(--radius); padding: 16px; }

/* 练习 */
.quiz-area { max-width: 640px; margin: 0 auto; }
.q-block { margin-bottom: 24px; }
.q-head { font-weight: 600; margin-bottom: 12px; font-size: 16px; display: flex; justify-content: space-between; align-items: center; }
.q-progress { font-size: 13px; color: var(--text-light); font-weight: 400; }
.q-input {
  width: 100%;
  padding: 12px 14px;
  border: 2px solid var(--border);
  border-radius: 8px;
  font-size: 18px;
  letter-spacing: 1px;
}
.q-input:focus { outline: none; border-color: var(--primary); }
.q-options { display: grid; gap: 10px; }
.q-option {
  padding: 12px 16px;
  border: 2px solid var(--border);
  border-radius: 8px;
  cursor: pointer;
  font-size: 16px;
  transition: all .15s;
  background: #fff;
  text-align: left;
}
.q-option:hover:not(:disabled) { border-color: var(--primary); }
.q-option.correct { background: var(--success-light); border-color: var(--success); }
.q-option.wrong { background: var(--danger-light); border-color: var(--danger); }
.q-option:disabled { cursor: default; }

.result-panel { text-align: center; padding: 30px 20px; }
.result-panel .score { font-size: 52px; font-weight: 800; color: var(--primary); }
.result-panel .score-detail { color: var(--text-light); margin: 8px 0 20px; }

/* 拼写练习 */
.spell-word { font-size: 34px; font-weight: 800; text-align: center; margin: 10px 0; color: var(--primary); }
.spell-zh { text-align: center; font-size: 20px; margin-bottom: 6px; }
.spell-letters { text-align: center; font-size: 18px; margin-bottom: 16px; color: var(--text-light); }
.spell-input-wrap { max-width: 360px; margin: 0 auto; }
.spell-input {
  width: 100%;
  text-align: center;
  font-size: 28px;
  letter-spacing: 6px;
  padding: 12px;
  border: 2px solid var(--border);
  border-radius: 10px;
  text-transform: lowercase;
}
.spell-input:focus { outline: none; border-color: var(--primary); }

/* 反馈 */
.feedback { text-align: center; font-size: 16px; margin-top: 12px; min-height: 28px; font-weight: 600; }
.feedback.ok { color: var(--success); }
.feedback.bad { color: var(--danger); }

/* 音频按钮 */
.speak-btn {
  background: var(--primary-light);
  color: var(--primary);
  border: none;
  border-radius: 8px;
  padding: 6px 14px;
  cursor: pointer;
  font-size: 14px;
  margin-left: 8px;
}
.speak-btn:hover { background: var(--primary); color: #fff; }

/* 匹配题 */
.match-pair { display: flex; gap: 10px; align-items: center; margin-bottom: 10px; flex-wrap: wrap; }
.match-item {
  padding: 8px 14px;
  border: 2px solid var(--border);
  border-radius: 8px;
  cursor: pointer;
  font-size: 15px;
  background: #fff;
}
.match-item.selected { border-color: var(--primary); background: var(--primary-light); }
.match-item.done { border-color: var(--success); background: var(--success-light); cursor: default; }

/* 工具栏 */
.toolbar { display: flex; gap: 10px; margin-bottom: 16px; flex-wrap: wrap; align-items: center; }
.search-box {
  flex: 1;
  min-width: 200px;
  padding: 10px 14px;
  border: 2px solid var(--border);
  border-radius: 8px;
  font-size: 14px;
}
.search-box:focus { outline: none; border-color: var(--primary); }

/* 移动端适配 */
@media (max-width: 600px) {
  .container { padding: 14px 10px; }
  h1.page-title { font-size: 20px; }
  .word-grid { grid-template-columns: 1fr 1fr; }
  .spell-word { font-size: 28px; }
}

/* 加载遮罩 */
#app-loading {
  position: fixed; inset: 0; background: var(--bg);
  display: flex; align-items: center; justify-content: center;
  font-size: 18px; color: var(--text-light); z-index: 999;
}
.hidden { display: none !important; }