/*
 * 课本单词拼读（三年级上册）- 卡片展示
 * 视觉与 /english/phonics/short-vowels/ 一致：拼读分解 + 音素彩色 + 音节划分 + 例句
 * 额外增加 Unit / Lesson 筛选栏。
 */

/* Fonts: 微软雅黑优先（无外链） */
:root {
  --font-sans: "Microsoft YaHei", "PingFang SC", "Hiragino Sans GB", "Noto Sans CJK SC", "Source Han Sans SC", ui-sans-serif, system-ui, -apple-system, "Segoe UI", Roboto, "Helvetica Neue", Arial, "Noto Sans", "Liberation Sans", sans-serif;
  --font-display: var(--font-sans);

  /* Color Palette - Premium & Soft */
  --p-50: #eff6ff;
  --p-100: #dbeafe;
  --p-500: #3b82f6;
  --p-600: #2563eb;
  --p-700: #1d4ed8;

  --slate-50: #f8fafc;
  --slate-100: #f1f5f9;
  --slate-200: #e2e8f0;
  --slate-400: #94a3b8;
  --slate-600: #475569;
  --slate-800: #1e293b;
  --slate-900: #0f172a;

  /* Theme Tokens */
  --bg-main: var(--slate-50);
  --bg-card: #ffffff;
  --text-main: var(--slate-900);
  --text-muted: var(--slate-600);
  --border-soft: var(--slate-200);
  --accent: var(--p-600);

  /* Phoneme Colors - 彩虹渐变风格 */
  --phoneme-1: #3b82f6;  /* 蓝色 - 辅音 */
  --phoneme-2: #10b981;  /* 绿色 - 元音 */
  --phoneme-4: #8b5cf6;  /* 紫色 - 字母组合 */
  --phoneme-5: #ef4444;  /* 红色 - 高亮 */

  /* Shadows */
  --shadow-sm: 0 1px 2px rgba(0, 0, 0, 0.05);
  --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.1), 0 2px 4px -1px rgba(0, 0, 0, 0.06);
  --shadow-lg: 0 20px 25px -5px rgba(0, 0, 0, 0.1), 0 10px 10px -5px rgba(0, 0, 0, 0.04);

  /* Animation */
  --transition-smooth: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}

[data-theme="dark"] {
  --bg-main: #0b1120;
  --bg-card: #1e293b;
  --text-main: #f1f5f9;
  --text-muted: #cbd5e1;
  --border-soft: #334155;
  --accent: #60a5fa;
  --shadow-lg: 0 20px 25px -5px rgba(0, 0, 0, 0.3);
}

[data-theme="dark"] .sentence-en {
  color: #ffffff !important;
}

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

body {
  font-family: var(--font-sans);
  background-color: var(--bg-main);
  color: var(--text-main);
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
  transition: var(--transition-smooth);
  overflow-x: hidden;
}

h1, h2, h3 {
  font-family: var(--font-display);
}

/* --- Layout --- */
/* 顶部导航栏（fixed-top）占位：桌面 80px / 手机 72px，与整站 .site-container 一致 */
.container {
  max-width: 1100px;
  margin: 0 auto;
  padding-top: 0;
  padding-bottom: 0;
  padding-left: calc(2rem + env(safe-area-inset-left));
  padding-right: calc(2rem + env(safe-area-inset-right));
}

#main {
  padding-top: 84px;
  padding-bottom: 48px;
}

@media (max-width: 767.98px) {
  #main {
    padding-top: 72px;
    padding-bottom: 36px;
  }
}

/* --- Filter Bar（Unit / Lesson 筛选） --- */
.filter-box {
  position: relative;
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 0.8rem;
  padding: 1rem 1.25rem;
  background: var(--bg-card);
  border: 1px solid var(--border-soft);
  border-radius: 20px;
  margin-bottom: 1.5rem;
}

.filter-field {
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

.filter-field label {
  font-size: 0.9rem;
  color: var(--text-muted);
  font-weight: 500;
  white-space: nowrap;
}

/* 筛选下拉：原生 <select> 的系统面板无法跟随站点配色，改为按钮 + 自定义面板 */
.filter-select-wrap {
  position: relative;
}

.filter-select {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  padding: 0.55rem 1rem;
  border-radius: 100px;
  border: 1px solid var(--border-soft);
  background-color: var(--bg-main);
  color: var(--text-main);
  font-family: var(--font-sans);
  font-size: 0.95rem;
  font-weight: 600;
  cursor: pointer;
  transition: var(--transition-smooth);
  -webkit-tap-highlight-color: transparent;
}

.filter-select-text {
  white-space: nowrap;
}

.filter-select-arrow {
  flex: 0 0 auto;
  color: var(--slate-400);
  transition: transform 0.25s ease;
}

.filter-select:focus-visible {
  outline: none;
  border-color: var(--accent);
}

.filter-select.active {
  border-color: var(--accent);
  color: var(--accent);
}

.filter-select.active .filter-select-arrow {
  color: var(--accent);
  transform: rotate(180deg);
}

@media (hover: hover) and (pointer: fine) {
  .filter-select:hover {
    border-color: var(--accent);
  }
}

/* 下拉面板：与卡片同款圆角 + 站点配色 */
.filter-menu {
  position: absolute;
  top: calc(100% + 6px);
  left: 0;
  z-index: 1300;
  min-width: 100%;
  width: max-content;
  max-width: calc(100vw - 2.5rem);
  max-height: 60vh;
  overflow-y: auto;
  padding: 0.35rem;
  background: var(--bg-card);
  border: 1px solid var(--border-soft);
  border-radius: 16px;
  box-shadow: var(--shadow-lg);
  display: flex;
  flex-direction: column;
  gap: 0.1rem;
}

.filter-menu.align-right {
  left: auto;
  right: 0;
}

.filter-option {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
  width: 100%;
  padding: 0.6rem 0.8rem;
  border: none;
  border-radius: 12px;
  background: transparent;
  color: var(--text-main);
  font-family: var(--font-sans);
  font-size: 0.95rem;
  font-weight: 500;
  text-align: left;
  white-space: nowrap;
  cursor: pointer;
  transition: var(--transition-smooth);
  -webkit-tap-highlight-color: transparent;
}

@media (hover: hover) and (pointer: fine) {
  .filter-option:hover {
    background: var(--bg-main);
  }
}

.filter-option:active {
  transform: scale(0.98);
}

/* 选中项：底色与卡片左上角「单词列表」里当前词一致（--bg-main + 主题色文字） */
.filter-option.active {
  color: var(--accent);
  font-weight: 700;
  background: var(--bg-main);
}

.filter-option-check {
  flex: 0 0 auto;
  color: var(--accent);
}

/* 筛选栏里「连读」自动靠右（左侧留给筛选下拉） */
.filter-box .auto-play-btn {
  margin-left: auto;
}

/* 设置弹层里的「颜色说明」折叠区（原筛选栏「说明」按钮/弹层已移入这里） */
.legend-toggle {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
  width: 100%;
  margin-top: 0.15rem;
  padding-top: 0.6rem;
  border: none;
  border-top: 1px dashed var(--border-soft);
  background: transparent;
  color: var(--text-main);
  font-family: var(--font-sans);
  font-size: 0.92rem;
  font-weight: 600;
  cursor: pointer;
  transition: var(--transition-smooth);
  -webkit-tap-highlight-color: transparent;
}

.legend-toggle svg {
  flex: 0 0 auto;
  color: var(--slate-400);
  transition: transform 0.25s ease;
}

.legend-toggle.active svg {
  transform: rotate(180deg);
}

@media (hover: hover) and (pointer: fine) {
  .legend-toggle:hover {
    color: var(--accent);
  }
}

.legend-body {
  display: flex;
  flex-direction: column;
  gap: 0.55rem;
  padding-top: 0.35rem;
}

/* 说明正文：手机/平板竖屏单列；桌面两列（色卡 + 用法提示） */
.legend-cols {
  display: grid;
  grid-template-columns: 1fr;
  gap: 0.6rem;
}

.legend-note {
  margin-top: 0.5rem;
  padding-top: 0.55rem;
  border-top: 1px dashed var(--border-soft);
  font-size: 0.78rem;
  color: var(--slate-400);
}

.legend-list {
  list-style: none;
  margin: 0;
  padding: 0;
  display: flex;
  flex-direction: column;
  gap: 0.5rem;
  font-size: 0.88rem;
  color: var(--text-main);
}

.legend-list li {
  display: flex;
  align-items: flex-start;
  gap: 0.5rem;
  line-height: 1.5;
}

.legend-list b {
  font-weight: 700;
}

.dot {
  flex: 0 0 auto;
  width: 12px;
  height: 12px;
  border-radius: 50%;
  margin-top: 0.35rem;
}

.dot-consonant {
  background: #3b82f6;
}

.dot-vowel {
  background: #10b981;
}

.dot-digraph {
  background: #8b5cf6;
}

.dot-silent {
  background: #94a3b8;
  opacity: 0.55;
}

.legend-tip {
  margin-top: 0.2rem;
  padding-top: 0.7rem;
  border-top: 1px dashed var(--border-soft);
  font-size: 0.82rem;
  color: var(--text-muted);
  display: flex;
  flex-direction: column;
  gap: 0.35rem;
  line-height: 1.55;
}

/* 桌面：说明与色卡并排，分隔线由横转竖 */
@media (min-width: 768px) {
  .legend-cols {
    grid-template-columns: 0.85fr 1.15fr; /* 色卡窄、提示宽，两列高度接近 */
    gap: 1rem;
  }

  .legend-tip {
    margin-top: 0;
    padding-top: 0;
    padding-left: 1rem;
    border-top: none;
    border-left: 1px dashed var(--border-soft);
  }
}

/* --- Practice View --- */
.practice-stage {
  margin-top: 0.5rem;
  position: relative;
}

.practice-header {
  text-align: center;
  margin-bottom: 1.5rem;
  cursor: pointer;
}

.practice-note {
  font-size: 0.85rem;
  color: var(--slate-400);
  margin-top: 0.5rem;
}

.practice-actions {
  display: block;
  text-align: center;
  margin-top: 1.75rem;
}

/* 底部工具行：标记生词 / 进度 / 遮住中文（桌面为普通行；移动端固定底部） */
.practice-actions-row {
  display: grid;
  grid-template-columns: 1fr auto 1fr;
  align-items: center;
  gap: 0.6rem;
  width: 100%;
  max-width: 800px;
  margin: 0 auto;
}

.practice-progress {
  /* 固定在中间列并自身居中：普通模式底栏只剩它一个元素时也不会被排到左列而偏左 */
  grid-column: 2;
  justify-self: center;
  text-align: center;
  margin: 0;
  color: var(--text-muted);
  font-size: 0.9rem;
  font-weight: 500;
  white-space: nowrap;
}

/* 工具按钮（标记生词 / 遮住中文） */
.tool-btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.35rem;
  min-height: 40px;
  padding: 0.45rem 0.9rem;
  border-radius: 12px;
  border: 1px solid var(--border-soft);
  background: var(--bg-card);
  color: var(--text-main);
  font-family: var(--font-sans);
  font-size: 0.9rem;
  font-weight: 600;
  cursor: pointer;
  white-space: nowrap;
  transition: var(--transition-smooth);
  -webkit-tap-highlight-color: transparent;
}

.practice-actions-row > .tool-btn:first-child {
  grid-column: 1;
  justify-self: start;
}

.practice-actions-row > .tool-btn:last-child {
  grid-column: 3;
  justify-self: end;
}

/* 听写模式的「上一词 / 下一词」：与短元音页一致（无边框文字按钮，.btn.nav-action） */
.practice-actions .nav-action {
  justify-content: center; /* 文字居中 */
  color: var(--text-main); /* 显式指定，避免 <button> 默认色在深色主题下发黑 */
}

/* 桌面端（≥769px，与卡片两侧箭头并存）隐藏这两个按钮，改用两侧箭头切换。
   注：卡片两侧箭头在 ≤768px 隐藏，故此处用 769px 分界，避免出现"两处都没有"的空档 */
@media (min-width: 769px) {
  .practice-actions .nav-action {
    display: none;
  }
}

.practice-actions .nav-action:disabled {
  opacity: 0.35;
  cursor: not-allowed;
}

.practice-actions-row > .nav-action:first-child {
  grid-column: 1;
  justify-self: start;
}

.practice-actions-row > .nav-action:last-child {
  grid-column: 3;
  justify-self: end;
}

@media (hover: hover) and (pointer: fine) {
  .tool-btn:hover {
    border-color: var(--accent);
  }
}

.tool-btn:active {
  transform: scale(0.96);
}

.tool-btn.active {
  color: #D93E3E;
  border-color: #D93E3E;
  background: rgba(255, 107, 107, 0.1);
}

.tool-icon {
  display: inline-flex;
  align-items: center;
}

.tool-btn:disabled {
  opacity: 0.35;
  cursor: not-allowed;
}

/* 卡片头部行中间：生词星标（纯星形；已标＝实心黄，未标＝空心灰描边） */
.mark-star-btn {
  grid-column: 2;
  justify-self: center;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 40px;
  height: 40px;
  border-radius: 50%;
  /* 淡底圆：一眼看出是可点按钮，而不是装饰图形 */
  background: rgba(148, 163, 184, 0.14);
  border: none;
  color: var(--slate-400);
  cursor: pointer;
  transition: var(--transition-smooth);
  -webkit-tap-highlight-color: transparent;
}

.mark-star-btn svg {
  fill: none;
  stroke: currentColor;
}

@media (hover: hover) and (pointer: fine) {
  .mark-star-btn:hover {
    color: var(--text-main);
  }
}

.mark-star-btn:active {
  transform: scale(0.9);
}

/* 已标生词：实心黄星 + 淡黄底色 */
.mark-star-btn.active {
  color: #F59E0B;
  background: rgba(251, 191, 36, 0.16);
}

.mark-star-btn.active svg {
  fill: #FBBF24;
  stroke: #F59E0B;
}

/* --- 听写占位（全遮挡）：点一下才显示答案 --- */
.dic-placeholder {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 0.75rem;
  width: 100%;
  padding: 0.5rem 0;
  cursor: pointer;
  -webkit-tap-highlight-color: transparent;
}

.dic-placeholder-icon {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 108px;
  height: 108px;
  border-radius: 50%;
  color: var(--accent);
  background: radial-gradient(circle at 32% 26%, rgba(59, 130, 246, 0.18), rgba(59, 130, 246, 0.05));
  border: 2px dashed var(--border-soft);
  animation: dicFloat 2.8s ease-in-out infinite;
}

@keyframes dicFloat {
  0%, 100% { transform: translateY(0); }
  50% { transform: translateY(-6px); }
}

.dic-placeholder-title {
  font-size: 1.25rem;
  font-weight: 700;
  color: var(--text-main);
}

.dic-placeholder-tip {
  font-size: 0.88rem;
  color: var(--text-muted);
}

.dic-replay-btn {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  margin-top: 0.4rem;
  padding: 0.5rem 1.1rem;
  border-radius: 100px;
  border: 1px solid var(--border-soft);
  background: var(--bg-main);
  color: var(--text-main);
  font-family: var(--font-sans);
  font-size: 0.92rem;
  font-weight: 600;
  cursor: pointer;
  transition: var(--transition-smooth);
  -webkit-tap-highlight-color: transparent;
}

@media (hover: hover) and (pointer: fine) {
  .dic-replay-btn:hover {
    color: var(--accent);
    border-color: var(--accent);
  }
}

.dic-replay-btn:active {
  transform: scale(0.96);
}

/* 遮住中文（自测）：隐藏释义与例句中文 */
.hide-cn .word-meaning,
.hide-cn .sentence-cn {
  display: none;
}

.cn-hidden-tip {
  font-size: 0.85rem;
  color: var(--slate-400);
  margin-bottom: 1rem;
}

/* --- Word Card --- */
.word-meta {
  font-size: 0.85rem;
  font-weight: 600;
  letter-spacing: 0.02em;
  color: var(--accent);
  margin-bottom: 0.75rem;
}

.word-phonetic {
  font-size: 1rem;
  color: var(--text-muted);
  margin-bottom: 0.25rem;
}

.word-main {
  font-family: ui-sans-serif, system-ui, -apple-system, "Segoe UI", Roboto, "Helvetica Neue", Arial, "Noto Sans", "Liberation Sans", sans-serif;
  font-size: 2.5rem;
  font-weight: 600;
  margin-bottom: 0.5rem;
  color: var(--text-main);
}

.flashcard .word-main {
  font-size: 4rem;
}

.word-highlight {
  color: var(--accent);
  text-decoration: underline;
  text-underline-offset: 6px;
  text-decoration-thickness: 3px;
}

.word-meaning {
  font-size: 1.1rem;
  color: var(--text-muted);
  font-weight: 400;
}

.flashcard .word-meaning {
  font-size: 1.5rem;
  margin-bottom: 2rem;
  color: var(--text-muted);
}

/* --- Phoneme Breakdown Colors --- */
.breakdown-display {
  display: flex;
  justify-content: center;
  align-items: center;
  gap: 0.2rem;
  margin: 1rem 0 2rem;
  flex-wrap: wrap;
}

.phoneme {
  display: inline-block;
  font-family: var(--font-display);
  font-size: clamp(2rem, 7vw, 3.5rem);
  font-weight: 700;
  padding: 0 0.2rem;
  line-height: 1;
  text-align: center;
  color: var(--phoneme-color, var(--text-main));
  background: none !important;
  box-shadow: none !important;
  border: none !important;
  min-width: auto;
  height: auto;
}

.phoneme:hover {
  transform: none !important;
}

.phoneme-vowel {
  border-radius: 0;
  width: auto;
  height: auto;
  min-width: auto;
  padding: 0 0.2rem;
}

.phoneme-digraph {
  min-width: auto;
  height: auto;
  padding: 0 0.2rem;
}

.phoneme-focus {
  text-shadow: 0 0 15px rgba(239, 68, 68, 0.4);
  animation: none;
}

.phoneme-sep {
  color: var(--border-soft);
  font-size: 2rem;
  font-weight: 300;
  margin: 0 0.5rem;
  display: inline-block;
  vertical-align: middle;
}

/* 静音字母：仅用灰色 + 降低不透明度表示，不用删除线（删除线压在小写 e 上会像多画一横） */
.phoneme-silent {
  color: var(--slate-400) !important;
  opacity: 0.5;
}

[data-theme="dark"] .phoneme-silent {
  color: var(--slate-400) !important;
  opacity: 0.45;
}

/* 音节分隔显示 */
.syllables-display {
  font-family: ui-sans-serif, system-ui, -apple-system, "Segoe UI", Roboto, "Helvetica Neue", Arial, "Noto Sans", "Liberation Sans", sans-serif;
  font-size: 1.1rem;
  font-weight: 500;
  color: var(--text-muted);
  margin: 0.5rem 0 1rem;
  display: flex;
  justify-content: center;
  align-items: center;
  gap: 0.3rem;
  letter-spacing: 0.15em;
}

/* --- Buttons --- */
.btn {
  padding: 0.8rem 2rem;
  border-radius: 12px;
  font-weight: 600;
  font-size: 1rem;
  cursor: pointer;
  transition: var(--transition-smooth);
  border: none;
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
}

.btn-primary {
  background: var(--accent);
  color: white;
}

/* 连读按钮（固定在筛选栏右侧）：常规态用主色实心按钮 */
.auto-play-btn {
  flex: 0 0 auto;
  margin-left: auto;
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 0.6rem 1.1rem;
  border-radius: 100px;
  background: #FF6B6B;
  border: 1px solid #D93E3E;
  color: #ffffff;
  font-weight: 600;
  font-size: 0.95rem;
  cursor: pointer;
  transition: var(--transition-smooth);
  -webkit-tap-highlight-color: transparent;
}

@media (hover: hover) and (pointer: fine) {
  .auto-play-btn:hover {
    background: #D93E3E;
    border-color: #D93E3E;
    color: #ffffff;
  }
}

.auto-play-btn:active {
  transform: scale(0.95);
}

.auto-play-btn.playing {
  background: #D93E3E;
  border-color: #D93E3E;
  color: #fff;
}

/* 「听写」按钮（筛选栏，与「连读」并排）：常规为幽灵按钮，进入听写后为主色实心 */
.dictation-btn {
  flex: 0 0 auto;
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 0.6rem 1.1rem;
  border-radius: 100px;
  background: var(--bg-main);
  border: 1px solid var(--border-soft);
  color: var(--text-muted);
  font-family: var(--font-sans);
  font-weight: 600;
  font-size: 0.95rem;
  cursor: pointer;
  transition: var(--transition-smooth);
  -webkit-tap-highlight-color: transparent;
}

@media (hover: hover) and (pointer: fine) {
  .dictation-btn:hover {
    color: var(--accent);
    border-color: var(--accent);
  }
}

.dictation-btn:active {
  transform: scale(0.95);
}

.dictation-btn.active {
  background: #6366F1;
  border-color: #4F46E5;
  color: #fff;
}

/* 听写态：隐藏「连读」「单词列表」等容易泄题的入口；
   设置弹层里的开关（朗读中文意思 / 随机顺序 / 遮住中文）在听写中都不生效，一并隐藏 */
.dictating .auto-play-btn,
.dictating .word-index-btn,
.dictating .word-index-pop,
.dictating .card-settings-btn,
.dictating .auto-settings-pop {
  display: none !important;
}

/* 卡片头部行右侧：更多设置按钮（竖排 3 圆点，自适应主题色） */
.card-settings-btn {
  grid-column: 3;
  justify-self: end;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 40px;
  height: 40px;
  border-radius: 50%;
  background: transparent;
  border: none;
  color: var(--text-muted);
  cursor: pointer;
  transition: var(--transition-smooth);
  -webkit-tap-highlight-color: transparent;
}

@media (hover: hover) and (pointer: fine) {
  .card-settings-btn:hover {
    color: var(--text-main);
  }
}

.card-settings-btn:active {
  transform: scale(0.95);
}

.card-settings-btn.active {
  color: var(--accent);
}

/* 卡片头部行左侧：单词列表按钮（竖排 3 圆点，自适应主题色） */
.word-index-btn {
  grid-column: 1;
  justify-self: start;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 40px;
  height: 40px;
  border-radius: 50%;
  background: transparent;
  border: none;
  color: var(--text-muted);
  cursor: pointer;
  transition: var(--transition-smooth);
  -webkit-tap-highlight-color: transparent;
}

@media (hover: hover) and (pointer: fine) {
  .word-index-btn:hover {
    color: var(--text-main);
  }
}

.word-index-btn:active {
  transform: scale(0.95);
}

.word-index-btn.active {
  color: var(--accent);
}

/* 单词列表弹层（紧贴头部行下方展开） */
.word-index-pop {
  position: absolute;
  top: calc(100% + 8px);
  left: 0;
  z-index: 1200;
  width: max-content;
  max-width: calc(100% - 2rem);
  max-height: 60vh;
  overflow-y: auto;
  scrollbar-width: none;
  -ms-overflow-style: none;
  padding: 0.5rem;
  background: var(--bg-card);
  border: 1px solid var(--border-soft);
  border-radius: 20px;
  box-shadow: var(--shadow-lg);
  text-align: left;
  display: flex;
  flex-direction: column;
  gap: 0.25rem;
}

.word-index-pop::-webkit-scrollbar {
  display: none;
}

.word-index-item {
  display: flex;
  align-items: baseline;
  gap: 0.6rem;
  width: 100%;
  text-align: left;
  padding: 0.7rem 0.8rem;
  border: none;
  border-radius: 14px;
  background: transparent;
  color: var(--text-main);
  font: inherit;
  cursor: pointer;
  transition: var(--transition-smooth);
  -webkit-tap-highlight-color: transparent;
}

@media (hover: hover) and (pointer: fine) {
  .word-index-item:hover {
    background: rgba(217, 62, 62, 0.1);
  }
}

[data-theme="dark"] .word-index-item:hover {
  background: rgba(217, 62, 62, 0.18);
}

.word-index-item.active {
  background: var(--bg-main);
  color: var(--accent);
}

.word-index-word {
  font-weight: 600;
  font-size: 1rem;
  flex: 0 0 auto;
}

.word-index-meaning {
  font-size: 0.88rem;
  color: var(--text-muted);
}

/* 显示设置弹层（紧贴头部行下方展开） */
.auto-settings-pop {
  position: absolute;
  top: calc(100% + 8px);
  right: 0;
  z-index: 1200;
  /* 宽度固定（不随「颜色说明」展开而变），避免展开瞬间“跳宽” */
  width: 300px;
  max-width: calc(100vw - 2.5rem);
  max-height: calc(100vh - 160px);
  overflow-y: auto;
  padding: 0.8rem 1rem;
  background: var(--bg-card);
  border: 1px solid var(--border-soft);
  border-radius: 14px;
  box-shadow: var(--shadow-lg);
  text-align: left;
  display: flex;
  flex-direction: column;
  gap: 0.7rem;
}

/* 桌面端弹层更宽，说明可用两列排布 */
@media (min-width: 768px) {
  .auto-settings-pop {
    width: 380px;
  }
}

@media (min-width: 1024px) {
  .auto-settings-pop {
    width: 420px;
  }
}

/* 小手机：弹层宽度贴合屏幕（左右各留 1.75rem） */
@media (max-width: 599.98px) {
  .auto-settings-pop {
    width: calc(100vw - 3.5rem);
    max-width: none;
  }
}

.auto-opt {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
  font-size: 0.92rem;
  color: var(--text-main);
  cursor: pointer;
  white-space: nowrap;
}

/* 开关 */
.switch {
  position: relative;
  display: inline-block;
  width: 42px;
  height: 24px;
  flex: 0 0 auto;
}

.switch input {
  position: absolute;
  opacity: 0;
  width: 100%;
  height: 100%;
  margin: 0;
  cursor: pointer;
}

.switch .slider {
  position: absolute;
  inset: 0;
  background: var(--slate-400);
  border-radius: 100px;
  transition: var(--transition-smooth);
}

.switch .slider::before {
  content: "";
  position: absolute;
  width: 18px;
  height: 18px;
  left: 3px;
  top: 3px;
  background: #fff;
  border-radius: 50%;
  transition: var(--transition-smooth);
}

.switch input:checked + .slider {
  background: #D93E3E;
}

.switch input:checked + .slider::before {
  transform: translateX(18px);
}

/* --- Flashcard Navigation --- */
.flashcard-wrapper {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 2rem;
  max-width: 800px;
  margin: 0 auto;
}

.flashcard {
  position: relative;
  flex: 1;
  min-height: 450px;
  display: flex;
  flex-direction: column;
  align-items: stretch; /* 头部行铺满宽度；正文在 .card-body 内居中 */
  text-align: center;
  padding: 2rem 3rem 3rem;
  border-radius: 32px;
  background: var(--bg-card);
  border: 1px solid var(--border-soft);
  box-shadow: var(--shadow-sm);
  transition: transform 0.4s cubic-bezier(0.175, 0.885, 0.32, 1.275);
}

/* 卡片头部行：三个按钮真实占位（左＝单词列表 / 中＝生词星标 / 右＝显示设置），
   不再绝对定位浮在正文上，因此无论单词多长、内容多少都不会与正文重叠 */
.card-head {
  position: relative; /* 两个弹层相对本行定位 */
  flex: 0 0 auto;
  display: grid;
  grid-template-columns: 1fr auto 1fr; /* 显式三列：某列隐藏（听写态）也不影响其余对齐 */
  align-items: center;
  width: 100%;
  min-height: 40px;
}

/* 正文区：紧接头部行往下排（与星标固定间距 1rem），多余的空白全部留在卡片底部。
   这样「星标 ↔ 单词」的距离不随内容多少忽大忽小（居中时它=空白的一半）。 */
.card-body {
  flex: 1 1 auto;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: flex-start;
  width: 100%;
  padding-top: 0.4rem;
}

/* 听写遮罩态：占位图示回到卡片中垂直居中（此时不需要贴着头像行） */
.card-body-center {
  justify-content: center;
  padding-top: 0;
}

.nav-btn {
  width: 64px;
  height: 64px;
  border-radius: 50%;
  border: 1px solid var(--border-soft);
  background: var(--bg-card);
  color: var(--text-main);
  display: flex;
  align-items: center;
  justify-content: center;
  cursor: pointer;
  transition: var(--transition-smooth);
  flex-shrink: 0;
}

@media (hover: hover) {
  .nav-btn:hover:not(:disabled) {
    background: var(--accent);
    color: white;
    border-color: var(--accent);
  }
}

.nav-btn:disabled {
  opacity: 0.2;
  cursor: not-allowed;
}

/* --- Sentence Info --- */
.sentence-box {
  width: 100%;
  margin-top: 1rem;
  padding: 1.5rem;
  background: var(--bg-main);
  border-radius: 20px;
  cursor: pointer;
  transition: var(--transition-smooth);
  border: 1px solid transparent;
}

@media (hover: hover) {
  .sentence-box:hover {
    background: var(--p-50);
    border-color: var(--p-100);
  }

  [data-theme="dark"] .sentence-box:hover {
    background: rgba(255, 255, 255, 0.05);
    border-color: var(--accent);
  }
}

.sentence-en {
  font-size: 1.2rem;
  font-weight: 500;
  color: var(--text-main);
  margin-bottom: 0.4rem;
}

.sentence-cn {
  font-size: 1rem;
  color: var(--text-muted);
}

/* --- Loading --- */
.loading-tip {
  text-align: center;
  padding: 4rem 0;
  color: var(--text-muted);
}

/* --- Responsive Design --- */
@media (min-width: 768px) and (max-width: 1024px) {
  .container {
    padding-left: calc(2.5rem + env(safe-area-inset-left));
    padding-right: calc(2.5rem + env(safe-area-inset-right));
  }

  .flashcard-wrapper {
    max-width: 650px;
  }

  .flashcard {
    min-height: 400px;
    padding: 1.5rem 2.5rem 2.5rem; /* 上内边距减小：顶部已有 40px 的按钮行 */
  }

  .flashcard .word-main {
    font-size: 3.5rem;
  }
}

@media (max-height: 500px) and (orientation: landscape) {
  .practice-header {
    margin-bottom: 1rem;
  }

  .flashcard {
    min-height: 250px !important;
    padding: 0.75rem 1.5rem 1.25rem !important; /* 上内边距减小：顶部已有 40px 的按钮行 */
  }

  .flashcard .word-main {
    font-size: 2rem !important;
  }

  .flashcard .word-meaning {
    font-size: 1rem !important;
    margin-bottom: 0.75rem !important;
  }

  .breakdown-display {
    margin: 0.5rem 0 0.75rem;
  }

  .phoneme {
    font-size: 1.5rem !important;
  }

  .sentence-box {
    padding: 0.75rem;
  }
}

/* iOS Specific Optimizations */
@supports (-webkit-touch-callout: none) {
  .btn,
  .nav-btn,
  .sentence-box,
  .filter-select {
    -webkit-touch-callout: none;
    -webkit-user-select: none;
    user-select: none;
  }

  .flashcard {
    min-height: 50svh;
  }
}

/* Android Specific Optimizations */
@media (hover: none) and (pointer: coarse) {
  .btn {
    min-height: 48px;
  }
}

/* Small Phone Optimizations */
@media (max-width: 375px) {
  .container {
    padding-left: calc(1rem + env(safe-area-inset-left));
    padding-right: calc(1rem + env(safe-area-inset-right));
  }

  .flashcard {
    padding: 0.75rem 1rem 1.25rem !important; /* 上内边距减小：顶部已有 40px 的按钮行 */
  }

  .flashcard .word-main {
    font-size: 2rem !important;
  }

  .phoneme {
    font-size: 1.5rem !important;
  }
}

@media (max-width: 768px) {
  .container {
    padding-left: calc(1.25rem + env(safe-area-inset-left));
    padding-right: calc(1.25rem + env(safe-area-inset-right));
  }

  .flashcard-wrapper {
    gap: 0.5rem;
    position: relative;
  }

  /* 手机端隐藏左右按钮，主要靠滑动 */
  .nav-btn {
    display: none;
  }

  #current-flashcard {
    touch-action: pan-y;
  }

  .flashcard {
    padding: 1.25rem 1.5rem 2.5rem !important; /* 上内边距减小：顶部已有 40px 的按钮行 */
    min-height: 50vh;
    border-radius: 24px !important;
    box-shadow: var(--shadow-md);
  }

  @supports (height: 1dvh) {
    .flashcard {
      min-height: 50dvh;
    }
  }

  .flashcard .word-main {
    font-size: clamp(2.2rem, 9vw, 3rem) !important;
  }

  .practice-header {
    margin-bottom: 2rem;
  }

  .filter-box {
    padding: 0.9rem 1rem;
    gap: 0.6rem;
    margin-bottom: 1.25rem;
  }

  .mobile-hint {
    display: block !important;
  }
}

/* S 下段（小手机竖屏 <600px，断点见 design.md） */
@media (max-width: 599.98px) {
  .practice-stage {
    margin-top: 0.5rem;
    padding-bottom: calc(88px + env(safe-area-inset-bottom)); /* 与短元音页一致（底栏总高 ~68px） */
  }

  .practice-header {
    margin-bottom: 1.25rem;
  }

  /* 听写遮罩态（手机窄屏）：星号与耳机图标之间多留些间距（居中布局下等效下移 1rem） */
  .card-body-center {
    padding-top: 1.0rem;
  }

  .practice-actions {
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center; /* 固定高度后让内容垂直居中 */
    gap: 0.6rem;
    margin-top: 0;
    position: fixed;
    left: 0;
    right: 0;
    bottom: 0;
    /* 高度与短元音页一致（按钮 44px + 上下留白 0.75rem ≈ 68px）；
       普通模式底栏只剩进度数字时也保持同样高度，不会变矮 */
    min-height: calc(44px + 1.5rem + env(safe-area-inset-bottom));
    padding-top: 0.75rem;
    padding-left: calc(1.25rem + env(safe-area-inset-left));
    padding-right: calc(1.25rem + env(safe-area-inset-right));
    padding-bottom: calc(0.75rem + env(safe-area-inset-bottom));
    background: #ffffff;
    border-top: 1px solid var(--border-soft);
    box-shadow: 0 -6px 16px -10px rgba(15, 23, 42, 0.25);
    z-index: 1100;
  }

  [data-theme="dark"] .practice-actions {
    background: #10151d;
  }

  /* 底部栏按钮：与短元音页一致（各自撑满所在栅格列、触屏 44px 高） */
  .practice-actions .nav-action {
    width: 100%; /* 撑满所在栅格列（短元音页同款） */
  }

  .practice-actions .btn {
    min-height: 44px;
  }

  .flashcard {
    padding: 1rem 1.25rem 1.75rem !important; /* 上内边距减小：顶部已有 40px 的按钮行 */
    border-radius: 20px !important;
  }

  .breakdown-display {
    margin: 0.75rem 0 1.25rem;
  }

  .phoneme-sep {
    margin: 0 0.25rem;
  }

  .word-meaning {
    font-size: 1.15rem !important;
    margin-bottom: 1.25rem !important;
  }

  .flashcard .word-meaning {
    font-size: 1.15rem !important;
  }

  .sentence-box {
    padding: 1.1rem;
  }

  .sentence-en {
    font-size: 1.05rem;
  }

  .sentence-cn {
    font-size: 0.95rem;
  }

  .btn {
    min-height: 44px;
  }
}

/* Sentence Click/Active State Visibility Fix */
.sentence-box:active {
  background: var(--p-100);
  border-color: var(--p-600);
}

[data-theme="dark"] .sentence-box:active {
  background: var(--slate-800);
  border-color: var(--accent);
}

[data-theme="dark"] .sentence-box:active .sentence-en {
  color: var(--accent);
}

/* Reduced Motion Accessibility */
@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
  }

  .flashcard {
    transition: none;
  }
}

.mobile-hint {
  display: none;
}

/* 本页底部署名（仅本页） */
.page-credit {
  margin-top: 2.5rem;
  padding: 1.5rem 1rem 2rem;
  text-align: center;
  font-size: 0.9rem;
  color: var(--text-muted);
  border-top: 1px solid var(--slate-200);
}

[data-theme="dark"] .page-credit {
  border-top-color: var(--slate-800);
}

.page-credit a {
  color: var(--text-muted);
  text-decoration: underline;
  text-decoration-color: var(--border-soft);
  text-underline-offset: 3px;
  transition: var(--transition-smooth);
}

.page-credit a:hover {
  color: var(--text-main);
  text-decoration-color: currentColor;
}