/* ==========================================================================
   文言小游 (Wenyanwen App) - CSS Design System & Theme Styling
   ========================================================================== */

:root {
  /* 浅色古风宣纸配色方案 (Warm Xuan Paper & Ink Palette) */
  --bg-primary: #fcf9f2;
  --bg-secondary: #f4eee1;
  --bg-card: #ffffff;
  --bg-glass: rgba(255, 255, 255, 0.85);

  --text-main: #1c1917;
  --text-muted: #57534e;
  --text-light: #78716c;

  --accent-ink: #1e293b;
  --accent-vermillion: #b91c1c; /* 朱砂红 */
  --accent-vermillion-light: #fef2f2;
  --accent-bamboo: #15803d;    /* 竹青 */
  --accent-bamboo-light: #f0fdf4;
  --accent-amber: #b45309;     /* 琥珀黄 */
  --accent-amber-light: #fffbeb;
  --accent-indigo: #4338ca;    /* 黛蓝 */
  --accent-indigo-light: #eef2ff;

  --border-color: #e7e5e4;
  --border-hover: #d6d3d1;

  --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.05);
  --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.08), 0 2px 4px -1px rgba(0, 0, 0, 0.04);
  --shadow-lg: 0 10px 25px -5px rgba(0, 0, 0, 0.12), 0 8px 10px -6px rgba(0, 0, 0, 0.04);
  --shadow-glow: 0 0 15px rgba(185, 28, 28, 0.2);

  --font-serif: 'Noto Serif SC', 'KaiTi', 'STKaiti', serif;
  --font-calligraphy: 'Ma Shan Zheng', 'Noto Serif SC', serif;
  --font-sans: 'Outfit', -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;

  --radius-sm: 6px;
  --radius-md: 10px;
  --radius-lg: 16px;
  --radius-full: 9999px;

  --transition-fast: all 0.18s cubic-bezier(0.4, 0, 0.2, 1);
  --transition-normal: all 0.28s cubic-bezier(0.4, 0, 0.2, 1);
}

/* 深色模式配色 (Dark Midnight Ink Stone Theme) */
body.dark-mode {
  --bg-primary: #0c1017;
  --bg-secondary: #161c28;
  --bg-card: #1e2536;
  --bg-glass: rgba(30, 37, 54, 0.85);

  --text-main: #f1f5f9;
  --text-muted: #94a3b8;
  --text-light: #64748b;

  --accent-ink: #f8fafc;
  --accent-vermillion: #ef4444;
  --accent-vermillion-light: rgba(239, 68, 68, 0.15);
  --accent-bamboo: #4ade80;
  --accent-bamboo-light: rgba(74, 222, 128, 0.15);
  --accent-amber: #f59e0b;
  --accent-amber-light: rgba(245, 158, 11, 0.15);
  --accent-indigo: #818cf8;
  --accent-indigo-light: rgba(129, 140, 248, 0.15);

  --border-color: #2e374a;
  --border-hover: #414d66;

  --shadow-md: 0 4px 12px rgba(0, 0, 0, 0.4);
  --shadow-lg: 0 12px 30px rgba(0, 0, 0, 0.6);
}

/* 重置与基础 */
* {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

body {
  font-family: var(--font-sans);
  background-color: var(--bg-primary);
  color: var(--text-main);
  line-height: 1.6;
  transition: background-color 0.3s ease, color 0.3s ease;
  min-height: 100vh;
}

/* 背景纹理微效果 */
body::before {
  content: "";
  position: fixed;
  top: 0;
  left: 0;
  width: 100vw;
  height: 100vh;
  background-image: radial-gradient(var(--border-color) 1px, transparent 1px);
  background-size: 24px 24px;
  opacity: 0.3;
  pointer-events: none;
  z-index: 0;
}

.app-container {
  position: relative;
  z-index: 1;
  max-width: 1440px;
  margin: 0 auto;
  padding: 16px 24px;
  display: flex;
  flex-direction: column;
  min-height: 100vh;
}

/* 顶部 Header */
.app-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 16px 24px;
  background: var(--bg-glass);
  backdrop-filter: blur(12px);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-sm);
  margin-bottom: 20px;
}

.header-brand {
  display: flex;
  align-items: center;
  gap: 14px;
}

.brand-logo {
  width: 46px;
  height: 46px;
  background: linear-gradient(135deg, var(--accent-vermillion), #7f1d1d);
  color: #ffffff;
  border-radius: var(--radius-md);
  display: flex;
  align-items: center;
  justify-content: center;
  box-shadow: var(--shadow-glow);
}

.logo-character {
  font-family: var(--font-calligraphy);
  font-size: 28px;
  line-height: 1;
}

.brand-title h1 {
  font-family: var(--font-serif);
  font-size: 22px;
  font-weight: 700;
  color: var(--text-main);
  letter-spacing: 1px;
}

.brand-subtitle {
  font-size: 12px;
  color: var(--text-muted);
}

/* 搜索与全局控制 */
.header-controls {
  display: flex;
  align-items: center;
  gap: 12px;
}

.search-box {
  position: relative;
  width: 280px;
}

.search-icon {
  position: absolute;
  left: 12px;
  top: 50%;
  transform: translateY(-50%);
  width: 18px;
  height: 18px;
  color: var(--text-light);
}

.search-box input {
  width: 100%;
  padding: 9px 12px 9px 38px;
  border-radius: var(--radius-full);
  border: 1px solid var(--border-color);
  background: var(--bg-card);
  color: var(--text-main);
  font-size: 13.5px;
  outline: none;
  transition: var(--transition-fast);
}

.search-box input:focus {
  border-color: var(--accent-vermillion);
  box-shadow: 0 0 0 3px var(--accent-vermillion-light);
}

/* 按钮通用 */
.btn {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 8px 16px;
  border-radius: var(--radius-full);
  font-size: 13px;
  font-weight: 600;
  cursor: pointer;
  border: 1px solid transparent;
  transition: var(--transition-fast);
}

.btn-secondary {
  background: var(--accent-amber-light);
  color: var(--accent-amber);
  border-color: rgba(245, 158, 11, 0.3);
}
.btn-secondary:hover {
  background: var(--accent-amber);
  color: #ffffff;
}

.btn-outline {
  background: transparent;
  border-color: var(--border-color);
  color: var(--text-main);
}
.btn-outline:hover {
  border-color: var(--accent-vermillion);
  color: var(--accent-vermillion);
  background: var(--accent-vermillion-light);
}

.theme-toggle-btn {
  width: 38px;
  height: 38px;
  border-radius: 50%;
  border: 1px solid var(--border-color);
  background: var(--bg-card);
  color: var(--text-main);
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 16px;
  transition: var(--transition-fast);
}

.theme-toggle-btn:hover {
  background: var(--bg-secondary);
  transform: rotate(15deg);
}

/* 主体 Grid 布局 */
.main-layout {
  display: grid;
  grid-template-columns: 320px 1fr;
  gap: 24px;
  flex: 1;
}

/* 左侧栏 Sidebar */
.sidebar {
  display: flex;
  flex-direction: column;
  gap: 16px;
}

.category-tabs {
  display: flex;
  flex-wrap: wrap;
  gap: 4px;
  background: var(--bg-card);
  padding: 6px;
  border-radius: var(--radius-md);
  border: 1px solid var(--border-color);
}

.tab-btn {
  flex: 1;
  padding: 7px 10px;
  border: none;
  background: transparent;
  color: var(--text-muted);
  font-size: 12.5px;
  font-weight: 600;
  border-radius: var(--radius-sm);
  cursor: pointer;
  transition: var(--transition-fast);
}

.tab-btn.active {
  background: var(--bg-primary);
  color: var(--accent-vermillion);
  box-shadow: var(--shadow-sm);
}

.article-list-container {
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-lg);
  padding: 16px;
  flex: 1;
  display: flex;
  flex-direction: column;
  max-height: 480px;
}

.section-title {
  display: flex;
  justify-content: space-between;
  align-items: center;
  font-size: 13px;
  font-weight: 700;
  color: var(--text-muted);
  margin-bottom: 12px;
  padding-bottom: 8px;
  border-bottom: 1px solid var(--border-color);
}

.count-badge {
  background: var(--bg-secondary);
  color: var(--text-muted);
  padding: 2px 8px;
  border-radius: var(--radius-full);
  font-size: 11px;
}

.article-list {
  list-style: none;
  overflow-y: auto;
  display: flex;
  flex-direction: column;
  gap: 8px;
  padding-right: 4px;
}

.article-item {
  padding: 12px 14px;
  border-radius: var(--radius-md);
  border: 1px solid var(--border-color);
  background: var(--bg-primary);
  cursor: pointer;
  transition: var(--transition-fast);
}

.article-item:hover {
  border-color: var(--accent-vermillion);
  transform: translateY(-1px);
  box-shadow: var(--shadow-sm);
}

.article-item.active {
  background: var(--accent-vermillion-light);
  border-color: var(--accent-vermillion);
}

.item-top {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 4px;
}

.item-title {
  font-family: var(--font-serif);
  font-size: 15px;
  font-weight: 700;
  color: var(--text-main);
}

.item-author {
  font-size: 12px;
  color: var(--text-muted);
}

.item-summary {
  font-size: 12px;
  color: var(--text-light);
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}

/* 快捷虚词芯片卡 */
.quick-keywords-card {
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-lg);
  padding: 16px;
}

.quick-keywords-card h4 {
  font-size: 12px;
  color: var(--text-muted);
  margin-bottom: 10px;
}

.keyword-chips {
  display: flex;
  flex-wrap: wrap;
  gap: 6px;
}

.chip-btn {
  padding: 4px 10px;
  border-radius: var(--radius-sm);
  border: 1px solid var(--border-color);
  background: var(--bg-primary);
  color: var(--accent-indigo);
  font-family: var(--font-serif);
  font-size: 14px;
  font-weight: 700;
  cursor: pointer;
  transition: var(--transition-fast);
}

.chip-btn:hover {
  background: var(--accent-indigo);
  color: #ffffff;
  border-color: var(--accent-indigo);
  transform: scale(1.05);
}

/* 右侧主内容区 */
.content-area {
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-lg);
  padding: 32px 40px;
  box-shadow: var(--shadow-sm);
  display: flex;
  flex-direction: column;
  gap: 24px;
}

.article-toolbar {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding-bottom: 16px;
  border-bottom: 1px solid var(--border-color);
}

.toolbar-left {
  display: flex;
  align-items: center;
  gap: 8px;
}

.category-badge {
  background: var(--accent-vermillion-light);
  color: var(--accent-vermillion);
  font-size: 12px;
  font-weight: 600;
  padding: 3px 10px;
  border-radius: var(--radius-full);
}

.difficulty-badge {
  background: var(--accent-bamboo-light);
  color: var(--accent-bamboo);
  font-size: 12px;
  font-weight: 600;
  padding: 3px 10px;
  border-radius: var(--radius-full);
}

.dynasty-tag {
  font-size: 13px;
  color: var(--text-muted);
  font-family: var(--font-serif);
}

.toolbar-right {
  display: flex;
  align-items: center;
  gap: 16px;
}

/* 开关 Toggle */
.toggle-switch {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  cursor: pointer;
  font-size: 12.5px;
  color: var(--text-muted);
  user-select: none;
}

.toggle-switch input {
  display: none;
}

.slider {
  width: 34px;
  height: 18px;
  background-color: var(--border-color);
  border-radius: 99px;
  position: relative;
  transition: var(--transition-fast);
}

.slider::before {
  content: "";
  position: absolute;
  width: 14px;
  height: 14px;
  left: 2px;
  top: 2px;
  background-color: #ffffff;
  border-radius: 50%;
  transition: var(--transition-fast);
}

.toggle-switch input:checked + .slider {
  background-color: var(--accent-bamboo);
}

.toggle-switch input:checked + .slider::before {
  transform: translateX(16px);
}

/* 文章头部 */
.article-header {
  text-align: center;
  max-width: 680px;
  margin: 0 auto;
}

.article-title {
  font-family: var(--font-serif);
  font-size: 32px;
  font-weight: 900;
  color: var(--text-main);
  margin-bottom: 8px;
  letter-spacing: 2px;
}

.article-summary {
  font-size: 14px;
  color: var(--text-muted);
  margin-bottom: 12px;
}

.article-tags {
  display: flex;
  justify-content: center;
  gap: 6px;
}

.tag-item {
  font-size: 11px;
  background: var(--bg-secondary);
  color: var(--text-light);
  padding: 2px 8px;
  border-radius: var(--radius-sm);
}

/* 正文阅读区排版 */
.reading-container {
  display: flex;
  flex-direction: column;
  gap: 28px;
  max-width: 820px;
  margin: 0 auto;
  width: 100%;
}

.paragraph-block {
  background: var(--bg-primary);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  padding: 20px 24px;
  transition: var(--transition-fast);
}

.paragraph-block:hover {
  border-color: var(--border-hover);
  box-shadow: var(--shadow-sm);
}

.sentence-row {
  margin-bottom: 16px;
}
.sentence-row:last-child {
  margin-bottom: 0;
}

.original-sentence {
  font-family: var(--font-serif);
  font-size: 22px;
  line-height: 1.9;
  color: var(--text-main);
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  gap: 2px 1px;
}

/* 逐字 Word Element */
.word-unit {
  display: inline-flex;
  flex-direction: column;
  align-items: center;
  position: relative;
  padding: 2px 4px;
  border-radius: var(--radius-sm);
  cursor: pointer;
  transition: var(--transition-fast);
}

.word-unit:hover {
  background: var(--accent-vermillion-light);
  color: var(--accent-vermillion);
}

/* 标注高频 key 词汇 */
.word-unit.has-key {
  border-bottom: 2px dashed var(--accent-indigo);
}

.word-unit.is-special {
  background: var(--accent-amber-light);
}

/* 拼音排版 */
.word-pinyin {
  font-family: var(--font-sans);
  font-size: 11px;
  color: var(--text-light);
  line-height: 1;
  margin-bottom: 2px;
}

.word-char {
  font-size: 22px;
  font-weight: 600;
}

.sentence-translation {
  font-size: 13.5px;
  color: var(--text-muted);
  margin-top: 6px;
  padding-left: 6px;
  border-left: 3px solid var(--accent-bamboo);
  background: var(--accent-bamboo-light);
  padding: 6px 12px;
  border-radius: 0 var(--radius-sm) var(--radius-sm) 0;
}

/* 字典 Tooltip 浮层 */
.dict-tooltip {
  position: absolute;
  z-index: 100;
  width: 260px;
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  box-shadow: var(--shadow-lg);
  padding: 14px;
  transition: opacity 0.15s ease, transform 0.15s ease;
}

.dict-tooltip.hidden {
  display: none;
  opacity: 0;
  pointer-events: none;
}

.dict-header {
  display: flex;
  align-items: center;
  gap: 8px;
  margin-bottom: 8px;
  padding-bottom: 6px;
  border-bottom: 1px solid var(--border-color);
}

.dict-char {
  font-family: var(--font-serif);
  font-size: 24px;
  font-weight: 700;
  color: var(--accent-vermillion);
}

.dict-pinyin {
  font-size: 13px;
  color: var(--text-muted);
}

.dict-pos-badge {
  margin-left: auto;
  font-size: 10.5px;
  background: var(--accent-indigo-light);
  color: var(--accent-indigo);
  padding: 2px 6px;
  border-radius: var(--radius-sm);
}

.dict-meaning {
  font-size: 13px;
  color: var(--text-main);
  line-height: 1.5;
  margin-bottom: 12px;
}

.btn-analogy {
  width: 100%;
  background: var(--accent-amber-light);
  color: var(--accent-amber);
  border: 1px dashed var(--accent-amber);
  padding: 6px 10px;
  border-radius: var(--radius-sm);
  font-size: 12px;
  font-weight: 600;
  cursor: pointer;
  transition: var(--transition-fast);
}

.btn-analogy:hover {
  background: var(--accent-amber);
  color: #ffffff;
}

/* 侧边 Drawer 抽屉 (举一反三分析器) */
.drawer-overlay {
  position: fixed;
  inset: 0;
  background: rgba(0, 0, 0, 0.4);
  backdrop-filter: blur(4px);
  z-index: 200;
  transition: opacity 0.3s ease;
}

.drawer-overlay.hidden {
  display: none;
}

.analogy-drawer {
  position: fixed;
  top: 0;
  right: 0;
  width: 480px;
  height: 100vh;
  background: var(--bg-card);
  z-index: 201;
  box-shadow: var(--shadow-lg);
  display: flex;
  flex-direction: column;
  transition: transform 0.3s cubic-bezier(0.16, 1, 0.3, 1);
}

.analogy-drawer.hidden {
  transform: translateX(100%);
}

.drawer-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 20px 24px;
  border-bottom: 1px solid var(--border-color);
  background: var(--bg-secondary);
}

.drawer-badge {
  font-size: 11px;
  color: var(--accent-amber);
  background: var(--accent-amber-light);
  padding: 2px 8px;
  border-radius: var(--radius-full);
  font-weight: 600;
}

.drawer-title-group h3 {
  font-family: var(--font-serif);
  font-size: 18px;
  margin-top: 4px;
}

.close-drawer-btn {
  background: transparent;
  border: none;
  font-size: 24px;
  color: var(--text-muted);
  cursor: pointer;
}

.drawer-body {
  padding: 24px;
  overflow-y: auto;
  flex: 1;
  display: flex;
  flex-direction: column;
  gap: 20px;
}

.analogy-instances-container h4 {
  font-size: 13px;
  color: var(--text-muted);
  margin-bottom: 12px;
}

.analogy-list {
  display: flex;
  flex-direction: column;
  gap: 12px;
}

.analogy-card {
  background: var(--bg-primary);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  padding: 14px 16px;
  transition: var(--transition-fast);
}

.analogy-card:hover {
  border-color: var(--accent-indigo);
  box-shadow: var(--shadow-sm);
}

.analogy-card-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 6px;
}

.analogy-source {
  font-size: 12.5px;
  font-weight: 700;
  color: var(--accent-indigo);
}

.analogy-pos {
  font-size: 11px;
  background: var(--bg-secondary);
  color: var(--text-muted);
  padding: 1px 6px;
  border-radius: var(--radius-sm);
}

.analogy-sentence {
  font-family: var(--font-serif);
  font-size: 16px;
  color: var(--text-main);
  margin-bottom: 4px;
}

.analogy-highlight {
  color: var(--accent-vermillion);
  font-weight: 700;
  text-decoration: underline;
}

.analogy-meaning {
  font-size: 12.5px;
  color: var(--text-muted);
}

/* Modal 自测弹窗 */
.modal-overlay {
  position: fixed;
  inset: 0;
  background: rgba(0, 0, 0, 0.5);
  backdrop-filter: blur(4px);
  z-index: 300;
  display: flex;
  align-items: center;
  justify-content: center;
}

.modal-overlay.hidden {
  display: none;
}

.quiz-modal {
  width: 520px;
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-lg);
  padding: 24px;
}

.modal-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 16px;
  padding-bottom: 10px;
  border-bottom: 1px solid var(--border-color);
}

.modal-header h3 {
  font-size: 16px;
  font-family: var(--font-serif);
}

.quiz-option {
  display: block;
  width: 100%;
  padding: 10px 14px;
  margin-top: 8px;
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  background: var(--bg-primary);
  text-align: left;
  cursor: pointer;
  font-size: 14px;
  transition: var(--transition-fast);
}

.quiz-option:hover {
  border-color: var(--accent-vermillion);
  background: var(--accent-vermillion-light);
}

.quiz-option.correct {
  background: var(--accent-bamboo-light);
  border-color: var(--accent-bamboo);
  color: var(--accent-bamboo);
}

.quiz-option.wrong {
  background: var(--accent-vermillion-light);
  border-color: var(--accent-vermillion);
  color: var(--accent-vermillion);
}

.modal-footer {
  margin-top: 20px;
  display: flex;
  justify-content: flex-end;
}

.btn-primary {
  background: var(--accent-vermillion);
  color: #ffffff;
  border: none;
}
.btn-primary:hover {
  background: #991b1b;
}

/* ========================================================================
   Hamburger button (hidden on desktop by default)
   ======================================================================== */
.sidebar-toggle-btn {
  display: none; /* hidden on desktop */
  width: 40px;
  height: 40px;
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  background: var(--bg-card);
  cursor: pointer;
  align-items: center;
  justify-content: center;
  flex-shrink: 0;
  transition: var(--transition-fast);
}

.sidebar-toggle-btn svg {
  width: 20px;
  height: 20px;
  color: var(--text-main);
}

.sidebar-toggle-btn:hover {
  background: var(--bg-secondary);
}

.header-left-group {
  display: flex;
  align-items: center;
  gap: 12px;
}

/* Sidebar overlay (hidden on desktop) */
.sidebar-overlay {
  display: none;
}

/* ========================================================================
   Mobile Responsive Layout (≤768px)
   ======================================================================== */
@media (max-width: 768px) {
  /* ─── Body & Container ─── */
  .app-container {
    padding: 8px 10px;
  }

  /* ─── Header ─── */
  .app-header {
    padding: 10px 12px;
    border-radius: var(--radius-md);
    margin-bottom: 10px;
    gap: 8px;
    flex-wrap: nowrap;
  }

  .sidebar-toggle-btn {
    display: flex; /* show hamburger on mobile */
  }

  .header-left-group {
    gap: 8px;
    flex-shrink: 0;
  }

  .brand-logo {
    width: 34px;
    height: 34px;
  }

  .logo-character {
    font-size: 20px;
  }

  .brand-title h1 {
    font-size: 16px;
    white-space: nowrap;
  }

  .brand-subtitle {
    display: none; /* hide subtitle on mobile to save space */
  }

  .header-controls {
    gap: 6px;
    flex-shrink: 1;
    min-width: 0;
  }

  /* Hide the text label on analogy hub button */
  #analogyHubBtn span:not(.btn-icon) {
    display: none;
  }

  #analogyHubBtn {
    padding: 8px 10px;
  }

  .search-box {
    display: none; /* hide search on mobile header; use sidebar for navigation */
  }

  .theme-toggle-btn {
    width: 34px;
    height: 34px;
    font-size: 14px;
  }

  /* ─── Main Layout: single column, sidebar hidden ─── */
  .main-layout {
    grid-template-columns: 1fr;
    gap: 0;
    position: relative;
  }

  /* ─── Sidebar as slide-in drawer ─── */
  .sidebar {
    position: fixed;
    top: 0;
    left: 0;
    width: 85vw;
    max-width: 340px;
    height: 100vh;
    height: 100dvh;
    background: var(--bg-card);
    z-index: 150;
    box-shadow: var(--shadow-lg);
    padding: 20px 16px;
    overflow-y: auto;
    transform: translateX(-100%);
    transition: transform 0.3s cubic-bezier(0.16, 1, 0.3, 1);
    -webkit-overflow-scrolling: touch;
  }

  .sidebar.mobile-open {
    transform: translateX(0);
  }

  /* Sidebar backdrop overlay */
  .sidebar-overlay {
    display: none;
    position: fixed;
    inset: 0;
    background: rgba(0, 0, 0, 0.45);
    backdrop-filter: blur(3px);
    z-index: 149;
    opacity: 0;
    transition: opacity 0.3s ease;
  }

  .sidebar-overlay.visible {
    display: block;
    opacity: 1;
  }

  /* Tweak sidebar internals for mobile */
  .category-tabs {
    gap: 3px;
    padding: 5px;
  }

  .tab-btn {
    padding: 8px 8px;
    font-size: 12px;
  }

  .article-list-container {
    max-height: none;
    flex: 1;
  }

  .article-item {
    padding: 10px 12px;
  }

  .item-title {
    font-size: 14px;
  }

  .quick-keywords-card {
    padding: 12px;
  }

  .chip-btn {
    padding: 6px 12px;
    font-size: 15px;
  }

  /* ─── Content Area ─── */
  .content-area {
    padding: 16px 14px;
    border-radius: var(--radius-md);
    gap: 16px;
  }

  /* ─── Article Toolbar: stack on mobile ─── */
  .article-toolbar {
    flex-direction: column;
    align-items: flex-start;
    gap: 10px;
    padding-bottom: 12px;
  }

  .toolbar-left {
    flex-wrap: wrap;
    gap: 6px;
  }

  .toolbar-right {
    flex-wrap: wrap;
    gap: 8px;
    width: 100%;
  }

  .toggle-switch {
    font-size: 12px;
  }

  .toggle-label {
    font-size: 11.5px;
  }

  /* ─── Article header ─── */
  .article-title {
    font-size: 24px;
    letter-spacing: 1px;
  }

  .article-summary {
    font-size: 13px;
  }

  /* ─── Reading area ─── */
  .reading-container {
    gap: 18px;
  }

  .paragraph-block {
    padding: 14px 12px;
  }

  .original-sentence {
    font-size: 19px;
    line-height: 1.85;
  }

  .word-char {
    font-size: 19px;
  }

  .word-unit {
    padding: 3px 3px;
  }

  .sentence-translation {
    font-size: 12.5px;
    padding: 5px 10px;
  }

  /* ─── Dictionary Tooltip: bottom sheet style on mobile ─── */
  .dict-tooltip {
    position: fixed !important;
    bottom: 0 !important;
    left: 0 !important;
    top: auto !important;
    right: 0 !important;
    width: 100vw !important;
    max-width: 100vw;
    border-radius: var(--radius-lg) var(--radius-lg) 0 0;
    box-shadow: 0 -4px 20px rgba(0, 0, 0, 0.15);
    padding: 18px 20px;
    padding-bottom: calc(18px + env(safe-area-inset-bottom, 0px));
    z-index: 120;
    animation: slideUpSheet 0.25s cubic-bezier(0.16, 1, 0.3, 1);
  }

  @keyframes slideUpSheet {
    from { transform: translateY(100%); opacity: 0; }
    to { transform: translateY(0); opacity: 1; }
  }

  .tooltip-arrow {
    display: none;
  }

  .dict-char {
    font-size: 28px;
  }

  .dict-pinyin {
    font-size: 15px;
  }

  .dict-meaning {
    font-size: 14px;
  }

  .btn-analogy {
    padding: 10px 14px;
    font-size: 13px;
  }

  /* ─── Analogy drawer: full screen on mobile ─── */
  .analogy-drawer {
    width: 100vw;
  }

  .drawer-header {
    padding: 16px 18px;
  }

  .drawer-title-group h3 {
    font-size: 16px;
  }

  .drawer-body {
    padding: 16px;
  }

  .analogy-card {
    padding: 12px 14px;
  }

  .analogy-sentence {
    font-size: 15px;
  }

  /* ─── Quiz modal: nearly full-width on mobile ─── */
  .quiz-modal {
    width: calc(100vw - 32px);
    max-width: 100%;
    padding: 18px;
    border-radius: var(--radius-lg);
  }

  .modal-header h3 {
    font-size: 15px;
  }

  .quiz-option {
    padding: 12px 14px;
    font-size: 14px;
  }
}