/* ==================== 全局样式 ==================== */

:root {
  /* 浅色主题 */
  --bg-primary: #f5f7fa;
  --bg-secondary: #ffffff;
  --bg-card: #ffffff;
  --text-primary: #2c3e50;
  --text-secondary: #7f8c8d;
  --accent-primary: #3498db;
  --accent-secondary: #2ecc71;
  --accent-danger: #e74c3c;
  --accent-warning: #f39c12;
  --border-color: #e1e8ed;
  --shadow: 0 2px 8px rgba(0, 0, 0, 0.1);
  --shadow-lg: 0 4px 16px rgba(0, 0, 0, 0.15);
}

[data-theme="dark"] {
  /* 深色主题 */
  --bg-primary: #1a1a2e;
  --bg-secondary: #16213e;
  --bg-card: #0f3460;
  --text-primary: #eaeaea;
  --text-secondary: #a0a0a0;
  --accent-primary: #5dade2;
  --accent-secondary: #52be80;
  --accent-danger: #ec7063;
  --accent-warning: #f8b739;
  --border-color: #2c3e50;
  --shadow: 0 2px 8px rgba(0, 0, 0, 0.3);
  --shadow-lg: 0 4px 16px rgba(0, 0, 0, 0.5);
}

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

body {
  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', 'PingFang SC', 'Microsoft YaHei', sans-serif;
  background-color: var(--bg-primary);
  color: var(--text-primary);
  line-height: 1.6;
  min-height: 100vh;
  transition: background-color 0.3s, color 0.3s;
}

/* ==================== 工具类 ==================== */

.hidden {
  display: none !important;
}

.screen {
  display: none;
}

.screen.active {
  display: block;
}

.header-center {
  flex: 1;
  min-width: 280px;
  display: flex;
  flex-direction: column;
  gap: 0.7rem;
}

.top-nav {
  display: flex;
  flex-wrap: wrap;
  gap: 0.6rem;
}

.top-nav-btn {
  border: 1px solid var(--border-color);
  background: var(--surface-strong);
  color: var(--text-secondary);
  border-radius: 999px;
  padding: 0.55rem 0.9rem;
  cursor: pointer;
  transition: all 0.2s;
  font-weight: 600;
}

.top-nav-btn.active,
.top-nav-btn:hover {
  color: var(--text-primary);
  border-color: rgba(85, 107, 96, 0.24);
  background: rgba(85, 107, 96, 0.08);
}

.breadcrumb {
  display: flex;
  flex-wrap: wrap;
  gap: 0.45rem;
  color: var(--text-secondary);
  font-size: 0.9rem;
}

.breadcrumb-item.current {
  color: var(--text-primary);
  font-weight: 600;
}

.hub-hero {
  margin-bottom: 1rem;
}

.module-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1rem;
}

.module-card {
  display: flex;
  flex-direction: column;
  align-items: flex-start;
  justify-content: flex-start;
  gap: 0.7rem;
  text-align: left;
  cursor: pointer;
  padding: 1.4rem;
  border-radius: 22px;
  border: 1px solid var(--border-color);
  background: var(--bg-card);
  transition: all 0.2s;
}

.module-card:hover {
  transform: translateY(-2px);
  box-shadow: var(--shadow);
}

.module-card-icon {
  width: 2.75rem;
  height: 2.75rem;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  border-radius: 16px;
  background: rgba(85, 107, 96, 0.08);
  color: var(--accent-primary);
}

.module-card-icon .icon {
  width: 1.2rem;
  height: 1.2rem;
}

.module-card-title {
  font-size: 1.1rem;
  font-weight: 700;
  color: var(--text-primary);
}

.module-card-desc {
  color: var(--text-secondary);
  font-size: 0.95rem;
  line-height: 1.7;
}

.danger-card {
  border-color: rgba(142, 95, 88, 0.2);
}

.single-column-grid {
  grid-template-columns: 1fr;
}

.compact-grid {
  margin-top: 1rem;
}

.wide-card {
  min-height: auto;
}

.module-view-card {
  display: flex;
  flex-direction: column;
  gap: 1.5rem;
}

.module-view-header {
  display: flex;
  flex-direction: column;
  gap: 0.5rem;
}

.section-back-btn {
  align-self: flex-start;
  margin-bottom: 0.25rem;
}

.section-title {
  font-size: 1.15rem;
  font-weight: 700;
  color: var(--text-primary);
  margin-bottom: 0.35rem;
}

.subtitle.compact {
  text-align: left;
  margin: 0 0 1rem;
  max-width: none;
}

.section-head-row {
  display: flex;
  justify-content: space-between;
  gap: 1rem;
  align-items: flex-start;
  flex-wrap: wrap;
}

.inline-actions {
  display: flex;
  gap: 0.75rem;
  flex-wrap: wrap;
}

.single-action-row {
  grid-template-columns: 1fr;
}

.no-divider {
  border-top: 0;
  padding-top: 0;
}

.selection-summary-card {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 1rem;
  padding: 1rem 1.1rem;
  border-radius: 20px;
  background: rgba(85, 107, 96, 0.05);
  border: 1px solid var(--border-color);
}

.selection-summary-item {
  display: flex;
  flex-direction: column;
  gap: 0.2rem;
}

.selection-summary-label {
  color: var(--text-secondary);
  font-size: 0.82rem;
  text-transform: uppercase;
  letter-spacing: 0.06em;
}

.progress-summary-grid,
.settings-grid {
  grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
}

/* ==================== 加载动画 ==================== */

.loading {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  min-height: 100vh;
  gap: 1rem;
}

.spinner {
  width: 50px;
  height: 50px;
  border: 4px solid var(--border-color);
  border-top-color: var(--accent-primary);
  border-radius: 50%;
  animation: spin 1s linear infinite;
}

@keyframes spin {
  to { transform: rotate(360deg); }
}

.loading p {
  color: var(--text-secondary);
  font-size: 1.1rem;
}

/* ==================== 主应用容器 ==================== */

.app {
  display: flex;
  flex-direction: column;
  min-height: 100vh;
  padding-left: 56px; /* 为侧边栏留出空间 */
}

/* ==================== 顶部导航栏 ==================== */

.header {
  background-color: var(--bg-secondary);
  padding: 1.5rem 2rem;
  box-shadow: var(--shadow);
  position: sticky;
  top: 0;
  z-index: 100;
}

.header h1 {
  font-size: 1.8rem;
  margin-bottom: 0.8rem;
  color: var(--accent-primary);
}

.header-stats {
  display: flex;
  gap: 2rem;
  flex-wrap: wrap;
}

.stat {
  color: var(--text-secondary);
  font-size: 0.95rem;
}

.stat strong {
  color: var(--text-primary);
  font-size: 1.1rem;
}

/* ==================== 主内容区 ==================== */

.main {
  flex: 1;
  padding: 2rem;
  max-width: 1200px;
  width: 100%;
  margin: 0 auto;
}

/* ==================== 欢迎页面 ==================== */

.welcome-card {
  background-color: var(--bg-card);
  border-radius: 16px;
  padding: 3rem;
  box-shadow: var(--shadow-lg);
}

.welcome-card h2 {
  font-size: 2rem;
  margin-bottom: 0.5rem;
  text-align: center;
}

.subtitle {
  text-align: center;
  color: var(--text-secondary);
  margin-bottom: 2.5rem;
  font-size: 1.1rem;
}

.level-buttons {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
  gap: 1.5rem;
  margin-bottom: 3rem;
}

.level-btn {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 0.5rem;
  padding: 2rem 1rem;
  background-color: var(--bg-secondary);
  border: 2px solid var(--border-color);
  border-radius: 12px;
  cursor: pointer;
  transition: all 0.3s;
  font-size: 1rem;
}

.level-btn:hover {
  transform: translateY(-4px);
  box-shadow: var(--shadow-lg);
  border-color: var(--accent-primary);
}

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

.level-icon {
  font-size: 2.5rem;
}

.level-name {
  font-weight: 600;
  font-size: 1.2rem;
}

.level-count {
  color: var(--text-secondary);
  font-size: 0.9rem;
}

.level-btn.selected .level-count {
  color: rgba(255, 255, 255, 0.9);
}

.mode-selection h3 {
  text-align: center;
  margin-bottom: 1.5rem;
  font-size: 1.5rem;
}

.mode-buttons {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
  gap: 1.5rem;
}

.mode-btn {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 0.5rem;
  padding: 2rem 1.5rem;
  background-color: var(--bg-secondary);
  border: 2px solid var(--border-color);
  border-radius: 12px;
  cursor: pointer;
  transition: all 0.3s;
}

.mode-btn:hover {
  transform: translateY(-4px);
  box-shadow: var(--shadow-lg);
  border-color: var(--accent-secondary);
}

.mode-icon {
  font-size: 2.5rem;
}

.mode-name {
  font-weight: 600;
  font-size: 1.1rem;
  color: var(--text-primary);
}

.mode-desc {
  color: var(--text-secondary);
  font-size: 0.9rem;
  text-align: center;
}

/* ==================== 欢迎页面区域分隔 ==================== */

.vocab-section {
  margin-bottom: 3rem;
}

.vocab-section h2,
.custom-wordbook-section h2,
.mode-selection h2 {
  font-size: 1.8rem;
  margin-bottom: 0.5rem;
  text-align: center;
}

/* ==================== 自定义单词本区域 ==================== */

.custom-wordbook-section {
  margin-bottom: 3rem;
  padding-top: 2rem;
  border-top: 2px solid var(--border-color);
}

/* ==================== 社区单词本区域 ==================== */

.community-wordbook-section {
  margin-bottom: 3rem;
  padding-top: 2rem;
  border-top: 2px solid var(--border-color);
}

/* ==================== 动词变位模块（欢迎页） ==================== */

.conjugation-module-section {
  margin-bottom: 3rem;
  padding-top: 2rem;
  border-top: 2px solid var(--border-color);
}

.conjugation-module-section h2 {
  font-size: 1.8rem;
  margin-bottom: 1rem;
  text-align: center;
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 0.6rem;
}

.conjugation-module-card {
  background-color: var(--bg-secondary);
  border: 2px solid var(--border-color);
  border-radius: 14px;
  padding: 1.2rem;
  transition: all 0.25s;
}

.conjugation-module-card.conj-context-active {
  border-color: var(--accent-primary);
  box-shadow: var(--shadow);
}

.conj-module-toolbar {
  display: flex;
  justify-content: center;
  align-items: center;
  flex-wrap: wrap;
  gap: 1rem;
  margin-bottom: 1rem;
}

.conj-module-toolbar label {
  display: flex;
  align-items: center;
  gap: 0.7rem;
  color: var(--text-secondary);
  font-size: 0.95rem;
}

.conj-module-toolbar select {
  min-width: 140px;
  padding: 0.55rem 0.75rem;
  border: 2px solid var(--border-color);
  border-radius: 8px;
  background-color: var(--bg-card);
  color: var(--text-primary);
  font-size: 0.95rem;
}

.conj-lesson-nav {
  display: flex;
  align-items: center;
  gap: 0.8rem;
  flex-wrap: wrap;
  justify-content: center;
}

.conj-lesson-status {
  display: flex;
  flex-direction: column;
  align-items: center;
  min-width: 110px;
}

#conjLessonLabel {
  font-weight: 600;
  color: var(--text-primary);
}

#conjLessonCompletedBadge {
  color: var(--accent-secondary);
  font-size: 0.9rem;
}

.conj-tense-buttons {
  display: flex;
  flex-direction: column;
  gap: 1rem;
}

.conj-tense-btn {
  padding: 0.75rem 0.6rem;
  min-height: 88px;
}

.conj-tense-btn .level-name {
  font-size: 0.96rem;
}

.conj-tense-btn .level-count {
  font-size: 0.78rem;
}

.conj-tense-matrix {
  display: grid;
  grid-template-columns: 120px repeat(3, minmax(0, 1fr));
  gap: 0.6rem;
}

.conj-matrix-head {
  display: flex;
  align-items: center;
  justify-content: center;
  border: 1px solid var(--border-color);
  border-radius: 10px;
  background: var(--bg-card);
  color: var(--text-secondary);
  font-weight: 600;
  min-height: 40px;
  font-size: 0.9rem;
}

.conj-matrix-row-label {
  display: flex;
  align-items: center;
  justify-content: center;
  border: 1px solid var(--border-color);
  border-radius: 10px;
  background: var(--bg-card);
  color: var(--text-primary);
  font-weight: 600;
  padding: 0.5rem;
  text-align: center;
}

.conj-matrix-cell {
  border: 1px solid var(--border-color);
  border-radius: 10px;
  background: var(--bg-card);
  padding: 0.55rem;
  display: grid;
  gap: 0.5rem;
  align-content: start;
}

.conj-matrix-empty {
  text-align: center;
  color: var(--text-secondary);
  padding: 0.7rem 0;
  font-size: 0.95rem;
}

.conj-extra-tenses {
  margin-top: 0.8rem;
}

.conj-extra-title {
  color: var(--text-secondary);
  font-size: 0.9rem;
  margin-bottom: 0.5rem;
}

.conj-extra-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(170px, 1fr));
  gap: 0.6rem;
}

.conj-module-hint {
  text-align: center;
  color: var(--text-secondary);
  font-size: 0.9rem;
  margin-top: 0.9rem;
}

/* ==================== 动词变位 — 移动端布局 ==================== */

.conj-mobile-layout {
  display: flex;
  flex-direction: column;
  gap: 0.75rem;
}

.conj-mobile-mood-section {
  border: 1px solid var(--border-color);
  border-radius: 16px;
  overflow: hidden;
}

.conj-mobile-mood-label {
  padding: 0.6rem 1rem;
  font-size: 0.82rem;
  font-weight: 700;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--text-secondary);
  background: rgba(85, 107, 96, 0.05);
  border-bottom: 1px solid var(--border-color);
}

.conj-mobile-mood-body {
  display: flex;
  flex-direction: column;
  gap: 0;
}

.conj-mobile-time-group {
  display: flex;
  align-items: flex-start;
  gap: 0.75rem;
  padding: 0.65rem 0.85rem;
  border-bottom: 1px solid var(--border-color);
}

.conj-mobile-time-group:last-child {
  border-bottom: none;
}

.conj-mobile-time-label {
  flex-shrink: 0;
  width: 2.4rem;
  padding-top: 0.55rem;
  font-size: 0.78rem;
  font-weight: 600;
  color: var(--text-secondary);
  text-align: right;
}

.conj-mobile-time-btns {
  flex: 1;
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
}

.conj-mobile-time-btns .conj-tense-btn {
  flex: 1 1 auto;
  min-width: 120px;
  min-height: 64px;
  padding: 0.6rem 0.75rem;
  border-radius: 14px;
}

.conj-mobile-time-btns .conj-tense-btn .level-name {
  font-size: 0.9rem;
}

.conj-mobile-time-btns .conj-tense-btn .level-count {
  font-size: 0.74rem;
}

.community-wordbook-section h2 {
  font-size: 1.8rem;
  margin-bottom: 1.5rem;
  text-align: center;
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 0.5rem;
}

.new-badge {
  display: inline-block;
  font-size: 0.9rem;
  padding: 0.2rem 0.6rem;
  background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
  color: white;
  border-radius: 12px;
  font-weight: 600;
  animation: pulse 2s ease-in-out infinite;
  box-shadow: 0 2px 8px rgba(102, 126, 234, 0.4);
}

@keyframes pulse {
  0%, 100% {
    transform: scale(1);
    opacity: 1;
  }
  50% {
    transform: scale(1.05);
    opacity: 0.9;
  }
}

.community-buttons {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
  gap: 1.5rem;
  margin-bottom: 1.5rem;
}

.community-buttons button {
  padding: 1.5rem 2rem;
  background-color: var(--bg-secondary);
  border: 2px solid var(--border-color);
  border-radius: 12px;
  cursor: pointer;
  font-size: 1.1rem;
  color: var(--text-primary);
  font-weight: 600;
  transition: all 0.3s;
}

.community-buttons button:hover {
  transform: translateY(-4px);
  box-shadow: var(--shadow-lg);
  border-color: var(--accent-primary);
  background-color: var(--accent-primary);
  color: white;
}

/* 社区上传模态框 */
.community-upload-modal .modal-content {
  max-width: 600px;
}

.community-upload-modal .form-group {
  margin-bottom: 1.5rem;
}

.community-upload-modal .form-group label {
  display: block;
  margin-bottom: 0.5rem;
  color: var(--text-primary);
  font-weight: 600;
  font-size: 0.95rem;
}

.community-upload-modal .form-input,
.community-upload-modal .form-select,
.community-upload-modal .form-textarea {
  width: 100%;
  padding: 0.8rem;
  border: 2px solid var(--border-color);
  border-radius: 8px;
  background-color: var(--bg-secondary);
  color: var(--text-primary);
  font-size: 1rem;
  font-family: inherit;
  transition: all 0.2s;
}

.community-upload-modal .form-input:focus,
.community-upload-modal .form-select:focus,
.community-upload-modal .form-textarea:focus {
  outline: none;
  border-color: var(--accent-primary);
  box-shadow: 0 0 0 3px rgba(52, 152, 219, 0.1);
}

.community-upload-modal .form-select {
  cursor: pointer;
}

.community-upload-modal .form-textarea {
  resize: vertical;
  min-height: 80px;
}

/* 标签选择器 */
.tag-selector {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(120px, 1fr));
  gap: 0.8rem;
  padding: 1rem;
  background-color: var(--bg-secondary);
  border: 2px solid var(--border-color);
  border-radius: 8px;
}

.tag-option {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  padding: 0.5rem 0.8rem;
  background-color: var(--bg-primary);
  border: 1px solid var(--border-color);
  border-radius: 6px;
  cursor: pointer;
  transition: all 0.2s;
}

.tag-option:hover {
  background-color: var(--accent-primary);
  border-color: var(--accent-primary);
  color: white;
}

.tag-option input[type="checkbox"] {
  cursor: pointer;
  width: 16px;
  height: 16px;
}

.tag-option label {
  cursor: pointer;
  margin: 0;
  font-size: 0.9rem;
  user-select: none;
  font-weight: 500;
}

.tag-option:has(input:checked) {
  background-color: var(--accent-primary);
  border-color: var(--accent-primary);
  color: white;
}

.file-input-wrapper {
  position: relative;
}

.file-input-label {
  display: inline-block;
  padding: 0.8rem 1.5rem;
  background-color: var(--accent-primary);
  color: white;
  border-radius: 8px;
  cursor: pointer;
  font-weight: 600;
  transition: all 0.2s;
}

.file-input-label:hover {
  background-color: var(--accent-secondary);
  transform: translateY(-2px);
  box-shadow: var(--shadow);
}

.file-input-wrapper input[type="file"] {
  position: absolute;
  left: -9999px;
}

.file-name {
  display: inline-block;
  margin-left: 1rem;
  color: var(--text-secondary);
  font-size: 0.9rem;
}

/* 社区浏览屏幕 */
.community-browse-screen {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  background-color: var(--bg-primary);
  z-index: 1001; /* Above header and footer */
  overflow-y: auto;
  padding: 1.5rem 2rem;
}

/* Hide header and footer when community browse screen is active */
body:has(#communityBrowseScreen:not(.hidden)) .header,
body:has(#communityBrowseScreen:not(.hidden)) .footer {
  display: none;
}

.community-browse-container {
  max-width: 1200px;
  margin: 0 auto;
}

.browse-screen-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 2rem;
  flex-wrap: wrap;
  gap: 1rem;
}

.browse-screen-header h2 {
  font-size: 2rem;
  color: var(--accent-primary);
  margin: 0;
}

.browse-filters {
  display: flex;
  gap: 1rem;
  margin-bottom: 2rem;
  flex-wrap: wrap;
  align-items: center;
}

.browse-filters .search-input {
  flex: 1;
  min-width: 250px;
  padding: 0.8rem 1rem;
  font-size: 1rem;
  border: 2px solid var(--border-color);
  border-radius: 8px;
  background-color: var(--bg-secondary);
  color: var(--text-primary);
  transition: all 0.2s;
}

.browse-filters .search-input:focus {
  outline: none;
  border-color: var(--accent-primary);
  box-shadow: 0 0 0 3px rgba(52, 152, 219, 0.1);
}

.filter-select {
  padding: 0.8rem 1.2rem;
  font-size: 1rem;
  border: 2px solid var(--border-color);
  border-radius: 8px;
  background-color: var(--bg-secondary);
  color: var(--text-primary);
  cursor: pointer;
  transition: all 0.2s;
  min-width: 150px;
}

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

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

/* 社区单词本列表 */
.community-wordbook-list {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
  gap: 1.5rem;
  margin-top: 2rem;
}

.community-wordbook-card {
  background-color: var(--bg-card);
  border: 2px solid var(--border-color);
  border-radius: 12px;
  padding: 1.5rem;
  transition: all 0.3s;
  cursor: pointer;
  display: flex;
  flex-direction: column;
}

.community-wordbook-card:hover {
  transform: translateY(-4px);
  box-shadow: var(--shadow-lg);
  border-color: var(--accent-primary);
}

.wordbook-card-header {
  display: flex;
  justify-content: space-between;
  align-items: flex-start;
  margin-bottom: 1rem;
}

.wordbook-card-title {
  flex: 1;
}

.wordbook-card-title h3 {
  font-size: 1.3rem;
  color: var(--accent-primary);
  margin-bottom: 0.3rem;
  word-wrap: break-word;
}

.wordbook-card-author {
  font-size: 0.9rem;
  color: var(--text-secondary);
}

.wordbook-card-difficulty {
  font-size: 1.5rem;
  margin-left: 0.5rem;
}

.wordbook-card-meta {
  display: flex;
  gap: 1rem;
  margin-bottom: 1rem;
  flex-wrap: wrap;
  font-size: 0.9rem;
  color: var(--text-secondary);
}

.wordbook-card-meta span {
  display: flex;
  align-items: center;
  gap: 0.3rem;
}

.wordbook-card-description {
  color: var(--text-primary);
  font-size: 0.95rem;
  margin-bottom: 1rem;
  line-height: 1.5;
  flex-grow: 1;
}

.wordbook-card-tags {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
  margin-bottom: 1rem;
}

.wordbook-tag {
  display: inline-block;
  padding: 0.3rem 0.8rem;
  background-color: var(--bg-secondary);
  border: 1px solid var(--border-color);
  border-radius: 12px;
  font-size: 0.85rem;
  color: var(--text-primary);
}

.wordbook-card-actions {
  display: flex;
  gap: 0.8rem;
  margin-top: auto;
}

.wordbook-card-actions button {
  flex: 1;
  padding: 0.7rem 1rem;
  border: none;
  border-radius: 8px;
  font-size: 0.95rem;
  font-weight: 600;
  cursor: pointer;
  transition: all 0.2s;
}

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

.wordbook-download-btn:hover {
  background-color: var(--accent-secondary);
  transform: translateY(-2px);
  box-shadow: var(--shadow);
}

.wordbook-preview-btn {
  background-color: var(--bg-secondary);
  color: var(--text-primary);
  border: 1px solid var(--border-color);
}

.wordbook-preview-btn:hover {
  background-color: var(--accent-primary);
  color: white;
  border-color: var(--accent-primary);
  transform: translateY(-2px);
}

/* 社区预览模态框 */
.community-preview-modal .modal-content {
  max-width: 700px;
}

.preview-meta {
  background-color: var(--bg-secondary);
  padding: 1.5rem;
  border-radius: 8px;
  margin-bottom: 1.5rem;
  border: 1px solid var(--border-color);
}

.preview-meta h3 {
  font-size: 1.5rem;
  color: var(--accent-primary);
  margin-bottom: 0.8rem;
}

.preview-meta p {
  margin-bottom: 0.5rem;
  color: var(--text-primary);
}

.preview-meta strong {
  color: var(--text-secondary);
  font-weight: 600;
}

.preview-tags {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
  margin: 1rem 0;
}

.preview-tags .wordbook-tag {
  background-color: var(--accent-primary);
  color: white;
  border-color: var(--accent-primary);
}

.preview-word-list {
  max-height: 400px;
  overflow-y: auto;
  padding: 1rem;
  background-color: var(--bg-secondary);
  border-radius: 8px;
  border: 1px solid var(--border-color);
}

.preview-word-list h4 {
  font-size: 1.1rem;
  margin-bottom: 1rem;
  color: var(--text-primary);
  position: sticky;
  top: 0;
  background-color: var(--bg-secondary);
  padding-bottom: 0.5rem;
  border-bottom: 2px solid var(--border-color);
}

.preview-word-item {
  padding: 0.8rem;
  margin-bottom: 0.5rem;
  background-color: var(--bg-primary);
  border-radius: 6px;
  border: 1px solid var(--border-color);
}

.preview-word-item-main {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 0.3rem;
}

.preview-word-italian {
  font-size: 1.1rem;
  font-weight: 600;
  color: var(--accent-primary);
}

.preview-word-english {
  color: var(--text-secondary);
  font-size: 0.95rem;
}

.preview-word-chinese {
  color: var(--accent-warning);
  font-size: 0.9rem;
  margin-top: 0.2rem;
}

.preview-actions {
  display: flex;
  justify-content: flex-end;
  gap: 1rem;
  margin-top: 1.5rem;
  padding-top: 1.5rem;
  border-top: 1px solid var(--border-color);
}

.preview-download-btn {
  padding: 0.8rem 2rem;
  background-color: var(--accent-primary);
  color: white;
  border: none;
  border-radius: 8px;
  font-size: 1rem;
  font-weight: 600;
  cursor: pointer;
  transition: all 0.2s;
}

.preview-download-btn:hover {
  background-color: var(--accent-secondary);
  transform: translateY(-2px);
  box-shadow: var(--shadow);
}

/* 加载状态 */
.loading-state {
  text-align: center;
  padding: 3rem;
  color: var(--text-secondary);
  font-size: 1.1rem;
}

.loading-state .spinner {
  margin: 0 auto 1rem;
}

/* 空状态 */
.empty-state {
  text-align: center;
  padding: 3rem;
  color: var(--text-secondary);
}

.empty-state-icon {
  font-size: 4rem;
  margin-bottom: 1rem;
  opacity: 0.5;
}

.empty-state p {
  font-size: 1.2rem;
}


.wordbook-cards {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
  gap: 1.5rem;
  margin-bottom: 1.5rem;
}

.wordbook-card {
  position: relative;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 0.5rem;
  padding: 2rem 1rem;
  background-color: var(--bg-secondary);
  border: 2px solid var(--border-color);
  border-radius: 12px;
  cursor: pointer;
  transition: all 0.3s;
}

.wordbook-card:hover {
  transform: translateY(-4px);
  box-shadow: var(--shadow-lg);
  border-color: var(--accent-primary);
}

.wordbook-card.selected {
  background-color: var(--accent-primary);
  border-color: var(--accent-primary);
  color: white;
}

.wordbook-card-icon {
  font-size: 2.5rem;
}

.wordbook-card-name {
  font-weight: 600;
  font-size: 1.1rem;
  text-align: center;
  word-wrap: break-word;
  width: 100%;
}

.wordbook-card.selected .wordbook-card-name {
  color: white;
}

.wordbook-card-count {
  color: var(--text-secondary);
  font-size: 0.9rem;
  text-align: center;
}

.wordbook-card.selected .wordbook-card-count {
  color: rgba(255, 255, 255, 0.9);
}

.wordbook-card-date {
  color: var(--text-secondary);
  font-size: 0.85rem;
  text-align: center;
}

.wordbook-card.selected .wordbook-card-date {
  color: rgba(255, 255, 255, 0.8);
}

.wordbook-delete-btn {
  position: absolute;
  top: 0.5rem;
  right: 0.5rem;
  width: 28px;
  height: 28px;
  background-color: var(--accent-danger);
  color: white;
  border: none;
  border-radius: 50%;
  cursor: pointer;
  font-size: 1.2rem;
  line-height: 1;
  display: flex;
  align-items: center;
  justify-content: center;
  opacity: 0;
  transition: all 0.2s;
  z-index: 10;
}

.wordbook-card:hover .wordbook-delete-btn {
  opacity: 1;
}

.wordbook-delete-btn:hover {
  background-color: #c0392b;
  transform: scale(1.1);
}

.import-wordbook-card {
  text-align: center;
}

.import-btn {
  margin: 0 auto;
  max-width: 300px;
  border-style: dashed !important;
}

.import-btn:hover {
  border-style: solid !important;
}

.import-hint-small {
  margin-top: 0.5rem;
  font-size: 0.9rem;
  color: var(--text-secondary);
}

.import-hint-small a {
  color: var(--accent-primary);
  text-decoration: none;
  font-weight: 600;
}

.import-hint-small a:hover {
  text-decoration: underline;
}

/* ==================== 模式选择区域 ==================== */

.mode-selection {
  padding-top: 2rem;
  border-top: 2px solid var(--border-color);
}

.mode-btn:disabled {
  opacity: 0.5;
  cursor: not-allowed;
  transform: none !important;
}

.mode-btn:disabled:hover {
  border-color: var(--border-color);
  box-shadow: none;
}

/* ==================== Notes 字段样式 ==================== */

.word-notes {
  color: var(--accent-warning);
  font-size: 0.85rem;
  margin-top: 0.5rem;
  padding: 0.5rem;
  background-color: rgba(243, 156, 18, 0.1);
  border-left: 3px solid var(--accent-warning);
  border-radius: 4px;
  font-style: italic;
}

.quiz-notes {
  color: var(--text-secondary);
  font-size: 0.9rem;
  margin-top: 1rem;
  padding: 0.8rem;
  background-color: var(--bg-secondary);
  border-left: 3px solid var(--accent-warning);
  border-radius: 4px;
  text-align: left;
}

.quiz-notes strong {
  color: var(--accent-warning);
}

/* ==================== 测验容器 ==================== */

.quiz-container {
  max-width: 800px;
  margin: 0 auto;
}

.quiz-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 2rem;
  flex-wrap: wrap;
  gap: 1rem;
}

.back-btn {
  padding: 0.6rem 1.2rem;
  background-color: var(--bg-secondary);
  border: 1px solid var(--border-color);
  border-radius: 8px;
  cursor: pointer;
  font-size: 1rem;
  color: var(--text-primary);
  transition: all 0.2s;
}

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

.quiz-progress {
  font-size: 1.1rem;
  color: var(--text-secondary);
}

.quiz-score {
  color: var(--text-secondary);
}

.quiz-score strong {
  color: var(--accent-secondary);
  font-size: 1.1rem;
}

.quiz-card {
  background-color: var(--bg-card);
  border-radius: 16px;
  padding: 3rem;
  box-shadow: var(--shadow-lg);
  margin-bottom: 1.5rem;
}

.conj-controls {
  display: flex;
  gap: 1rem;
  align-items: end;
  flex-wrap: wrap;
  margin-bottom: 1rem;
  padding: 1rem;
  background-color: var(--bg-card);
  border-radius: 12px;
  box-shadow: var(--shadow);
}

#conjActiveLessonInfo {
  color: var(--text-primary);
  font-weight: 500;
}

.conj-controls label {
  display: flex;
  flex-direction: column;
  gap: 0.4rem;
  color: var(--text-secondary);
  font-size: 0.9rem;
}

.conj-controls select {
  min-width: 140px;
  padding: 0.6rem 0.8rem;
  border: 2px solid var(--border-color);
  border-radius: 8px;
  background-color: var(--bg-secondary);
  color: var(--text-primary);
  font-size: 0.95rem;
}

.conj-pronoun-line {
  margin-top: 0.8rem;
  color: var(--text-secondary);
  font-size: 1.05rem;
}

.conj-tense-line {
  margin-top: 0.5rem;
  color: var(--text-secondary);
  font-size: 1rem;
}

.conj-english-line {
  margin-top: 0.55rem;
  color: var(--text-secondary);
  font-size: 1rem;
}

.conj-full-section {
  display: flex;
  flex-direction: column;
  gap: 1rem;
  align-items: center;
}

.conj-full-grid {
  width: 100%;
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
  gap: 1rem;
}

.conj-full-item {
  display: flex;
  flex-direction: column;
  gap: 0.5rem;
  padding: 1rem;
  background-color: var(--bg-secondary);
  border: 2px solid var(--border-color);
  border-radius: 12px;
  transition: all 0.2s;
}

.conj-full-item.correct {
  border-color: var(--accent-secondary);
  background-color: rgba(46, 204, 113, 0.08);
}

.conj-full-item.incorrect {
  border-color: var(--accent-danger);
  background-color: rgba(231, 76, 60, 0.08);
}

.conj-full-label {
  font-weight: 600;
  color: var(--text-primary);
  text-align: left;
}

.conj-full-input {
  max-width: none;
  font-size: 1.15rem;
}

.conj-full-answer {
  font-size: 0.92rem;
  color: var(--text-secondary);
}

.question-section {
  text-align: center;
  margin-bottom: 2.5rem;
}

.question-label {
  color: var(--text-secondary);
  font-size: 1rem;
  margin-bottom: 1rem;
}

.italian-word, .english-word {
  font-size: 2.5rem;
  font-weight: 600;
  color: var(--accent-primary);
  margin: 0;
}

.chinese-hint {
  font-size: 1rem;
  color: var(--text-secondary);
  margin-top: 0.5rem;
  font-style: italic;
}

.hint-btn {
  margin-top: 1rem;
  padding: 0.6rem 1.2rem;
  background-color: var(--accent-warning);
  color: white;
  border: none;
  border-radius: 8px;
  cursor: pointer;
  font-size: 0.95rem;
  font-weight: 600;
  transition: all 0.2s;
  display: inline-flex;
  align-items: center;
  gap: 0.3rem;
}

.hint-btn:hover {
  background-color: #e67e22;
  transform: translateY(-2px);
  box-shadow: var(--shadow);
}

.pronunciation-btn {
  margin-top: 1rem;
  padding: 0.7rem 1.5rem;
  background-color: var(--accent-primary);
  color: white;
  border: none;
  border-radius: 8px;
  cursor: pointer;
  font-size: 0.95rem;
  font-weight: 600;
  transition: all 0.2s;
  display: inline-flex;
  align-items: center;
  gap: 0.3rem;
}

.pronunciation-btn:hover {
  background-color: var(--accent-secondary);
  transform: translateY(-2px);
  box-shadow: var(--shadow);
}

.pronunciation-btn:active {
  transform: translateY(0);
}

/* ==================== 选择题选项 ==================== */

.options-section {
  margin-top: 2rem;
}

.options-label {
  color: var(--text-secondary);
  margin-bottom: 1rem;
  text-align: center;
}

.options-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 1rem;
}

.option-btn {
  padding: 1.5rem;
  background-color: var(--bg-secondary);
  border: 2px solid var(--border-color);
  border-radius: 12px;
  cursor: pointer;
  font-size: 1rem;
  color: var(--text-primary);
  transition: all 0.2s;
  text-align: left;
  word-wrap: break-word;
}

.option-btn:hover:not(.correct):not(.incorrect):not(:disabled) {
  background-color: var(--accent-primary);
  color: white;
  border-color: var(--accent-primary);
  transform: translateY(-2px);
}

.option-btn.correct {
  background-color: var(--accent-secondary);
  color: white;
  border-color: var(--accent-secondary);
}

.option-btn.incorrect {
  background-color: var(--accent-danger);
  color: white;
  border-color: var(--accent-danger);
}

.option-btn:disabled {
  cursor: not-allowed;
  opacity: 0.6;
}

/* ==================== 拼写输入 ==================== */

.spelling-section {
  display: flex;
  flex-direction: column;
  gap: 1rem;
  align-items: center;
}

.spelling-input {
  width: 100%;
  max-width: 400px;
  padding: 1rem;
  font-size: 1.5rem;
  text-align: center;
  border: 2px solid var(--border-color);
  border-radius: 8px;
  background-color: var(--bg-secondary);
  color: var(--text-primary);
  transition: all 0.2s;
}

.spelling-input:focus {
  outline: none;
  border-color: var(--accent-primary);
  box-shadow: 0 0 0 3px rgba(52, 152, 219, 0.1);
}

.check-btn {
  padding: 0.8rem 2rem;
  background-color: var(--accent-primary);
  color: white;
  border: none;
  border-radius: 8px;
  font-size: 1.1rem;
  font-weight: 600;
  cursor: pointer;
  transition: all 0.2s;
}

.check-btn:hover {
  background-color: var(--accent-secondary);
  transform: translateY(-2px);
  box-shadow: var(--shadow);
}

.check-btn:disabled {
  background-color: var(--text-secondary);
  cursor: not-allowed;
  transform: none;
}

/* ==================== 反馈区域 ==================== */

.quiz-feedback {
  background-color: var(--bg-card);
  border-radius: 12px;
  padding: 1.5rem;
  text-align: center;
  box-shadow: var(--shadow);
}

.quiz-feedback.correct {
  background-color: rgba(46, 204, 113, 0.1);
  border: 2px solid var(--accent-secondary);
}

.quiz-feedback.incorrect {
  background-color: rgba(231, 76, 60, 0.1);
  border: 2px solid var(--accent-danger);
}

.feedback-text {
  font-size: 1.2rem;
  margin-bottom: 1rem;
  font-weight: 500;
}

.next-btn {
  padding: 0.8rem 2rem;
  background-color: var(--accent-primary);
  color: white;
  border: none;
  border-radius: 8px;
  font-size: 1rem;
  font-weight: 600;
  cursor: pointer;
  transition: all 0.2s;
}

.next-btn:hover {
  background-color: var(--accent-secondary);
  transform: translateY(-2px);
  box-shadow: var(--shadow);
}

/* ==================== 浏览模式 ==================== */

.browse-container {
  max-width: 1000px;
  margin: 0 auto;
}

.browse-header {
  display: flex;
  gap: 1rem;
  margin-bottom: 2rem;
  flex-wrap: wrap;
}

.search-input {
  flex: 1;
  min-width: 250px;
  padding: 0.8rem 1rem;
  font-size: 1rem;
  border: 2px solid var(--border-color);
  border-radius: 8px;
  background-color: var(--bg-secondary);
  color: var(--text-primary);
  transition: all 0.2s;
}

.search-input:focus {
  outline: none;
  border-color: var(--accent-primary);
}

.filter-btn {
  padding: 0.8rem 1.5rem;
  background-color: var(--bg-secondary);
  border: 2px solid var(--border-color);
  border-radius: 8px;
  cursor: pointer;
  font-size: 1rem;
  color: var(--text-primary);
  transition: all 0.2s;
}

.filter-btn:hover {
  border-color: var(--accent-primary);
}

.word-list {
  display: grid;
  gap: 0.5rem;
  max-height: 70vh;
  overflow-y: auto;
  padding: 0.5rem;
}

.word-item {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 1rem 1.5rem;
  background-color: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: 8px;
  transition: all 0.2s;
}

.word-item:hover {
  box-shadow: var(--shadow);
  transform: translateX(4px);
}

.word-item.mastered {
  background-color: rgba(46, 204, 113, 0.1);
  border-color: var(--accent-secondary);
}

.word-item-left {
  flex: 1;
}

.word-italian {
  font-size: 1.2rem;
  font-weight: 600;
  color: var(--accent-primary);
  margin-bottom: 0.3rem;
}

.word-english {
  color: var(--text-secondary);
  font-size: 0.95rem;
}

.word-chinese {
  color: var(--accent-warning);
  font-size: 0.9rem;
  margin-top: 0.2rem;
  font-style: italic;
}

.word-item-right {
  display: flex;
  align-items: center;
  gap: 1rem;
}

.word-rank {
  color: var(--text-secondary);
  font-size: 0.9rem;
  min-width: 80px;
  text-align: right;
}

.mastered-badge {
  padding: 0.3rem 0.8rem;
  background-color: var(--accent-secondary);
  color: white;
  border-radius: 12px;
  font-size: 0.85rem;
  font-weight: 600;
}

/* ==================== 左侧工具栏（侧边栏）==================== */

.sidebar {
  position: fixed;
  left: 0;
  top: 0;
  bottom: 0;
  width: 56px;
  background-color: var(--bg-secondary);
  box-shadow: 2px 0 8px rgba(0, 0, 0, 0.1);
  display: flex;
  flex-direction: column;
  align-items: flex-start;
  padding: 1rem 0;
  z-index: 200;
  overflow: hidden;
  transition: width 0.25s ease;
}

.sidebar:hover {
  width: 160px;
}

.sidebar-btn {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  width: 100%;
  padding: 0.85rem 1rem;
  background: none;
  border: none;
  cursor: pointer;
  color: var(--text-secondary);
  font-size: 0.95rem;
  font-family: inherit;
  white-space: nowrap;
  transition: background-color 0.2s, color 0.2s;
  text-align: left;
}

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

.sidebar-icon {
  font-size: 1.4rem;
  flex-shrink: 0;
  width: 36px;
  text-align: center;
}

.sidebar-label {
  font-size: 0.9rem;
  font-weight: 500;
  opacity: 0;
  transition: opacity 0.2s ease;
  overflow: hidden;
}

.sidebar:hover .sidebar-label {
  opacity: 1;
}

.mobile-floating-back {
  position: fixed;
  right: 1rem;
  bottom: calc(88px + env(safe-area-inset-bottom, 0px));
  z-index: 320;
  display: none;
  align-items: center;
  gap: 0.45rem;
  min-height: 48px;
  padding: 0.85rem 1rem;
  border: 1px solid rgba(85, 107, 96, 0.16);
  border-radius: 999px;
  background: rgba(29, 36, 32, 0.88);
  color: #f7f5f0;
  box-shadow: 0 16px 36px rgba(0, 0, 0, 0.18);
  backdrop-filter: blur(12px);
  cursor: pointer;
}

.mobile-floating-back .icon {
  width: 0.95rem;
  height: 0.95rem;
}

.mobile-floating-back:hover {
  transform: translateY(-1px);
}

/* ==================== 弹窗 ==================== */

.modal {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  background-color: rgba(0, 0, 0, 0.6);
  display: flex;
  align-items: center;
  justify-content: center;
  z-index: 1000;
  padding: 1rem;
}

.modal-content {
  background-color: var(--bg-card);
  border-radius: 16px;
  max-width: 500px;
  width: 100%;
  box-shadow: var(--shadow-lg);
  max-height: 90vh;
  overflow-y: auto;
}

.modal-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 1.5rem 2rem;
  border-bottom: 1px solid var(--border-color);
}

.modal-header h3 {
  font-size: 1.5rem;
  margin: 0;
}

.close-btn {
  background: none;
  border: none;
  font-size: 2rem;
  cursor: pointer;
  color: var(--text-secondary);
  line-height: 1;
  padding: 0;
  width: 32px;
  height: 32px;
  display: flex;
  align-items: center;
  justify-content: center;
  border-radius: 50%;
  transition: all 0.2s;
}

.close-btn:hover {
  background-color: var(--border-color);
  color: var(--text-primary);
}

.modal-body {
  padding: 2rem;
}

.stat-item {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 1rem 0;
  border-bottom: 1px solid var(--border-color);
}

.stat-item:last-child {
  border-bottom: none;
}

.stat-label {
  color: var(--text-secondary);
  font-size: 1rem;
}

.stat-value {
  font-size: 1.2rem;
  font-weight: 600;
  color: var(--accent-primary);
}

/* ==================== 响应式设计 ==================== */

@media (max-width: 768px) {
  .header {
    padding: 1rem;
  }

  .header h1 {
    font-size: 1.4rem;
  }

  .header-stats {
    gap: 1rem;
  }

  .main {
    padding: 1rem;
  }

  .welcome-card {
    padding: 1.5rem;
  }

  .welcome-card h2 {
    font-size: 1.5rem;
  }

  .level-buttons {
    grid-template-columns: 1fr 1fr;
  }

  .mode-buttons {
    grid-template-columns: 1fr;
  }

  .quiz-card {
    padding: 1.5rem;
  }

  .conj-controls {
    flex-direction: column;
    align-items: stretch;
  }

  .italian-word, .english-word {
    font-size: 1.8rem;
  }

  .conj-full-grid {
    grid-template-columns: 1fr;
  }

  .options-grid {
    grid-template-columns: 1fr;
  }

  .browse-header {
    flex-direction: column;
  }

  /* 移动端侧边栏：隐藏，改为底部小图标栏 */
  .app {
    padding-left: 0;
    padding-bottom: 56px;
  }

  .sidebar {
    top: auto;
    bottom: 0;
    left: 0;
    right: 0;
    width: 100% !important;
    height: 56px;
    flex-direction: row;
    padding: 0;
    box-shadow: 0 -2px 8px rgba(0, 0, 0, 0.1);
    overflow: visible;
  }

  .sidebar:hover {
    width: 100% !important;
    height: 56px;
  }

  .sidebar-btn {
    flex: 1;
    flex-direction: column;
    gap: 0.2rem;
    padding: 0.4rem 0.2rem;
    justify-content: center;
    align-items: center;
  }

  .sidebar-icon {
    font-size: 1.3rem;
    width: auto;
  }

  .sidebar-label {
    font-size: 0.6rem;
    opacity: 1;
    white-space: nowrap;
  }

  .sidebar:hover .sidebar-label {
    opacity: 1;
  }

  /* 社区单词本响应式 */
  .community-buttons {
    grid-template-columns: 1fr;
  }

  .tag-selector {
    grid-template-columns: repeat(auto-fill, minmax(100px, 1fr));
  }

  .community-browse-screen {
    padding: 1rem;
  }

  .browse-screen-header h2 {
    font-size: 1.5rem;
  }

  .browse-filters {
    flex-direction: column;
  }

  .browse-filters .search-input {
    width: 100%;
  }

  .filter-select {
    width: 100%;
  }

  .community-wordbook-list {
    grid-template-columns: 1fr;
  }

  .wordbook-card-header {
    flex-direction: column;
    gap: 0.5rem;
  }

  .wordbook-card-difficulty {
    margin-left: 0;
  }

  .community-upload-modal .modal-content {
    max-width: 100%;
    margin: 0.5rem;
  }

  .community-preview-modal .modal-content {
    max-width: 100%;
    margin: 0.5rem;
  }
}

@media (max-width: 480px) {
  .level-buttons {
    grid-template-columns: 1fr;
  }

  .quiz-header {
    flex-direction: column;
    align-items: stretch;
  }

  .spelling-input {
    font-size: 1.2rem;
  }
}

/* ==================== 帮助弹窗样式 ==================== */

.help-modal-content {
  max-width: 900px;
  max-height: 85vh;
}

.help-modal-body {
  padding: 1.5rem 2rem;
  line-height: 1.8;
}

.help-section {
  margin-bottom: 2rem;
}

.help-section:last-child {
  margin-bottom: 0;
}

.help-section h2 {
  font-size: 1.8rem;
  color: var(--accent-primary);
  margin-bottom: 0.5rem;
}

.help-section h3 {
  font-size: 1.4rem;
  color: var(--text-primary);
  margin-bottom: 1rem;
  margin-top: 1.5rem;
  padding-bottom: 0.5rem;
  border-bottom: 2px solid var(--border-color);
}

.help-section h4 {
  font-size: 1.1rem;
  color: var(--accent-primary);
  margin-bottom: 0.5rem;
}

.help-intro {
  font-size: 1.1rem;
  color: var(--text-secondary);
  margin-bottom: 1rem;
}

.help-section ul {
  margin-left: 1.5rem;
  margin-bottom: 1rem;
}

.help-section ol {
  margin-left: 1.5rem;
  margin-bottom: 1rem;
}

.help-section li {
  margin-bottom: 0.5rem;
  color: var(--text-primary);
}

.help-section li ul,
.help-section li ol {
  margin-top: 0.5rem;
  margin-bottom: 0.5rem;
}

.help-section p {
  margin-bottom: 0.8rem;
  color: var(--text-primary);
}

.help-section code {
  background-color: var(--bg-primary);
  padding: 0.2rem 0.4rem;
  border-radius: 4px;
  font-family: 'Monaco', 'Courier New', monospace;
  font-size: 0.9rem;
  color: var(--accent-primary);
}

.feature-box {
  background-color: var(--bg-secondary);
  padding: 1.5rem;
  border-radius: 12px;
  margin-bottom: 1.5rem;
  border: 1px solid var(--border-color);
}

.feature-box.highlight {
  background-color: rgba(52, 152, 219, 0.05);
  border: 2px solid var(--accent-primary);
}

.feature-box h4 {
  margin-top: 0;
  margin-bottom: 1rem;
}

.code-block {
  background-color: var(--bg-primary);
  padding: 1rem;
  border-radius: 8px;
  border: 1px solid var(--border-color);
  font-family: 'Monaco', 'Courier New', monospace;
  font-size: 0.9rem;
  line-height: 1.6;
  overflow-x: auto;
  margin: 1rem 0;
  color: var(--text-primary);
  white-space: pre;
}

.usage-box {
  background-color: var(--bg-secondary);
  padding: 1.5rem;
  border-radius: 12px;
  margin-bottom: 1.5rem;
  border-left: 4px solid var(--accent-secondary);
}

.usage-box h4 {
  margin-top: 0;
  margin-bottom: 1rem;
  color: var(--accent-secondary);
}

.help-tip {
  background-color: rgba(243, 156, 18, 0.1);
  padding: 1rem;
  border-radius: 8px;
  border-left: 4px solid var(--accent-warning);
  margin: 1rem 0;
}

.help-footer {
  text-align: center;
  font-size: 1.2rem;
  font-weight: 600;
  color: var(--accent-primary);
  margin-top: 2rem;
  padding-top: 1.5rem;
  border-top: 2px solid var(--border-color);
}

/* 帮助弹窗响应式设计 */
@media (max-width: 768px) {
  .help-modal-content {
    max-width: 100%;
    margin: 0.5rem;
  }

  .help-modal-body {
    padding: 1rem;
  }

  .help-section h2 {
    font-size: 1.5rem;
  }

  .help-section h3 {
    font-size: 1.2rem;
  }

  .feature-box,
  .usage-box {
    padding: 1rem;
  }

  .code-block {
    font-size: 0.8rem;
    padding: 0.8rem;
  }
}

/* ==================== 新增功能样式 ==================== */

/* 单词本编辑器模态框 */
.editor-modal-content {
  max-width: 900px;
  max-height: 85vh;
}

.editor-modal-body {
  padding: 0;
}

.editor-toolbar {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 1rem 1.5rem;
  border-bottom: 1px solid var(--border-color);
  background-color: var(--bg-secondary);
}

.editor-toolbar-btn {
  padding: 0.6rem 1.2rem;
  background-color: var(--accent-primary);
  color: white;
  border: none;
  border-radius: 6px;
  cursor: pointer;
  font-size: 0.95rem;
  font-weight: 500;
  transition: all 0.2s;
}

.editor-toolbar-btn:hover {
  background-color: var(--accent-secondary);
  transform: translateY(-1px);
}

.editor-toolbar-btn.danger {
  background-color: var(--accent-danger);
}

.editor-toolbar-btn.danger:hover {
  background-color: #c0392b;
}

.editor-batch-actions {
  display: flex;
  gap: 0.5rem;
}

.editor-word-list {
  max-height: 60vh;
  overflow-y: auto;
  padding: 1rem;
}

.editor-word-item {
  display: flex;
  align-items: center;
  gap: 1rem;
  padding: 1rem;
  background-color: var(--bg-secondary);
  border: 1px solid var(--border-color);
  border-radius: 8px;
  margin-bottom: 0.5rem;
  transition: all 0.2s;
}

.editor-word-item:hover {
  box-shadow: var(--shadow);
}

.word-checkbox {
  width: 18px;
  height: 18px;
  cursor: pointer;
}

.editor-word-content {
  flex: 1;
}

.editor-word-main {
  display: flex;
  gap: 1rem;
  margin-bottom: 0.3rem;
}

.editor-word-italian {
  font-size: 1.1rem;
  font-weight: 600;
  color: var(--accent-primary);
}

.editor-word-english {
  color: var(--text-secondary);
}

.editor-word-chinese {
  color: var(--accent-warning);
  font-size: 0.9rem;
  margin-top: 0.2rem;
}

.editor-word-notes {
  color: var(--text-secondary);
  font-size: 0.85rem;
  margin-top: 0.3rem;
  font-style: italic;
}

.editor-word-actions {
  display: flex;
  gap: 0.5rem;
}

.editor-action-btn {
  width: 36px;
  height: 36px;
  background-color: var(--bg-primary);
  border: 1px solid var(--border-color);
  border-radius: 6px;
  cursor: pointer;
  font-size: 1.2rem;
  display: flex;
  align-items: center;
  justify-content: center;
  transition: all 0.2s;
}

.editor-action-btn:hover {
  transform: scale(1.1);
  box-shadow: var(--shadow);
}

.editor-action-btn.edit:hover {
  background-color: var(--accent-primary);
  border-color: var(--accent-primary);
}

.editor-action-btn.delete:hover {
  background-color: var(--accent-danger);
  border-color: var(--accent-danger);
}

/* 表单样式 */
.form-group {
  margin-bottom: 1.2rem;
}

.form-group label {
  display: block;
  margin-bottom: 0.5rem;
  color: var(--text-primary);
  font-weight: 500;
}

.form-input,
.form-textarea {
  width: 100%;
  padding: 0.8rem;
  border: 2px solid var(--border-color);
  border-radius: 6px;
  background-color: var(--bg-secondary);
  color: var(--text-primary);
  font-size: 1rem;
  font-family: inherit;
  transition: all 0.2s;
}

.form-input:focus,
.form-textarea:focus {
  outline: none;
  border-color: var(--accent-primary);
  box-shadow: 0 0 0 3px rgba(52, 152, 219, 0.1);
}

.form-textarea {
  resize: vertical;
  min-height: 80px;
}

.form-actions {
  display: flex;
  justify-content: flex-end;
  gap: 1rem;
  margin-top: 1.5rem;
}

.form-btn {
  padding: 0.7rem 1.5rem;
  border: none;
  border-radius: 6px;
  font-size: 1rem;
  font-weight: 500;
  cursor: pointer;
  transition: all 0.2s;
}

.form-btn.cancel {
  background-color: var(--bg-secondary);
  color: var(--text-primary);
  border: 1px solid var(--border-color);
}

.form-btn.cancel:hover {
  background-color: var(--bg-primary);
}

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

.form-btn.primary:hover {
  background-color: var(--accent-secondary);
  transform: translateY(-1px);
  box-shadow: var(--shadow);
}

/* 单词本选择对话框 */
.wordbook-select-list {
  display: flex;
  flex-direction: column;
  gap: 0.5rem;
  max-height: 400px;
  overflow-y: auto;
}

.wordbook-select-item {
  display: flex;
  align-items: center;
  gap: 1rem;
  padding: 1rem;
  background-color: var(--bg-secondary);
  border: 2px solid var(--border-color);
  border-radius: 8px;
  cursor: pointer;
  transition: all 0.2s;
}

.wordbook-select-item:hover {
  border-color: var(--accent-primary);
  transform: translateX(4px);
  box-shadow: var(--shadow);
}

.wordbook-select-icon {
  font-size: 1.8rem;
}

.wordbook-select-info {
  flex: 1;
}

.wordbook-select-name {
  font-weight: 600;
  color: var(--text-primary);
  margin-bottom: 0.2rem;
}

.wordbook-select-count {
  font-size: 0.9rem;
  color: var(--text-secondary);
}

/* 浏览模式单词操作按钮 */
.word-actions {
  display: flex;
  gap: 0.5rem;
  margin-left: 1rem;
}

.word-action-btn {
  width: 32px;
  height: 32px;
  background-color: var(--bg-secondary);
  border: 1px solid var(--border-color);
  border-radius: 6px;
  cursor: pointer;
  font-size: 1.1rem;
  display: flex;
  align-items: center;
  justify-content: center;
  transition: all 0.2s;
}

.word-action-btn:hover {
  background-color: var(--accent-primary);
  border-color: var(--accent-primary);
  transform: scale(1.1);
}

/* 增强统计模态框 */
.enhanced-stats-modal {
  max-width: 1000px;
  max-height: 90vh;
}

.enhanced-stats-body {
  padding: 0;
}

/* 统计标签页 */
.stats-tabs {
  display: flex;
  border-bottom: 2px solid var(--border-color);
  background-color: var(--bg-secondary);
}

.stats-tab-btn {
  flex: 1;
  padding: 1rem;
  background: none;
  border: none;
  border-bottom: 3px solid transparent;
  cursor: pointer;
  font-size: 1rem;
  font-weight: 500;
  color: var(--text-secondary);
  transition: all 0.2s;
}

.stats-tab-btn:hover {
  background-color: var(--bg-primary);
  color: var(--text-primary);
}

.stats-tab-btn.active {
  color: var(--accent-primary);
  border-bottom-color: var(--accent-primary);
  background-color: var(--bg-primary);
}

.stats-tab-content {
  display: none;
  padding: 1.5rem;
}

.stats-tab-content.active {
  display: block;
}

/* 统计卡片 */
.stats-section {
  margin-bottom: 2rem;
}

.stats-section h4 {
  font-size: 1.3rem;
  margin-bottom: 1rem;
  color: var(--text-primary);
}

.stats-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
  gap: 1rem;
}

.stat-card {
  background-color: var(--bg-secondary);
  border: 1px solid var(--border-color);
  border-radius: 12px;
  padding: 1.5rem;
  text-align: center;
  transition: all 0.2s;
}

.stat-card:hover {
  transform: translateY(-2px);
  box-shadow: var(--shadow);
}

.stat-card-label {
  font-size: 0.9rem;
  color: var(--text-secondary);
  margin-bottom: 0.5rem;
}

.stat-card-value {
  font-size: 2rem;
  font-weight: 700;
  color: var(--accent-primary);
}

/* 图表容器 */
.chart-container {
  background-color: var(--bg-secondary);
  border: 1px solid var(--border-color);
  border-radius: 12px;
  padding: 1.5rem;
  margin-bottom: 1.5rem;
  height: 300px;
}

.charts-row {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 1.5rem;
}

.charts-row .chart-container {
  height: 300px;
}

/* 统计表格 */
.stats-table-container {
  overflow-x: auto;
  background-color: var(--bg-secondary);
  border: 1px solid var(--border-color);
  border-radius: 12px;
  padding: 1rem;
}

.stats-table {
  width: 100%;
  border-collapse: collapse;
}

.stats-table thead {
  background-color: var(--bg-primary);
}

.stats-table th {
  padding: 1rem;
  text-align: left;
  font-weight: 600;
  color: var(--text-primary);
  border-bottom: 2px solid var(--border-color);
}

.stats-table td {
  padding: 1rem;
  color: var(--text-secondary);
  border-bottom: 1px solid var(--border-color);
}

.stats-table tbody tr:hover {
  background-color: var(--bg-primary);
}

.stats-table tbody tr:last-child td {
  border-bottom: none;
}

/* 单词本卡片编辑按钮 */
.wordbook-card {
  position: relative;
}

.wordbook-card-manage-btn {
  position: absolute;
  top: 0.5rem;
  right: 3rem;
  width: 28px;
  height: 28px;
  background-color: var(--accent-primary);
  color: white;
  border: none;
  border-radius: 50%;
  cursor: pointer;
  font-size: 1rem;
  display: flex;
  align-items: center;
  justify-content: center;
  opacity: 0;
  transition: all 0.2s;
  z-index: 10;
}

.wordbook-card:hover .wordbook-card-manage-btn {
  opacity: 1;
}

.wordbook-card-manage-btn:hover {
  background-color: var(--accent-secondary);
  transform: scale(1.1);
}

/* 响应式设计 */
@media (max-width: 768px) {
  .editor-modal-content {
    max-width: 100%;
    margin: 0.5rem;
  }

  .editor-word-main {
    flex-direction: column;
    gap: 0.3rem;
  }

  .charts-row {
    grid-template-columns: 1fr;
  }

  .chart-container {
    height: 250px;
  }

  .stats-grid {
    grid-template-columns: 1fr;
  }

  .stats-tabs {
    flex-direction: column;
  }

  .enhanced-stats-modal {
    max-width: 100%;
    margin: 0.5rem;
  }

  .word-actions {
    flex-direction: column;
    gap: 0.3rem;
  }
}

@media (max-width: 480px) {
  .editor-toolbar {
    flex-direction: column;
    gap: 0.5rem;
  }

  .editor-batch-actions {
    width: 100%;
  }

  .editor-toolbar-btn {
    width: 100%;
  }

  .stat-card-value {
    font-size: 1.5rem;
  }
}

/* ==================== Premium minimalist redesign overrides ==================== */

:root {
  --bg-primary: #f3efe7;
  --bg-secondary: #faf7f1;
  --bg-card: rgba(255, 252, 247, 0.86);
  --text-primary: #1d2420;
  --text-secondary: #66706a;
  --accent-primary: #556b60;
  --accent-secondary: #7c8f84;
  --accent-danger: #8e5f58;
  --accent-warning: #8b7a63;
  --border-color: rgba(61, 74, 66, 0.12);
  --shadow: 0 10px 30px rgba(34, 40, 36, 0.07);
  --shadow-lg: 0 24px 60px rgba(34, 40, 36, 0.10);
  --surface-strong: rgba(255, 255, 255, 0.72);
}

[data-theme="dark"] {
  --bg-primary: #111614;
  --bg-secondary: #171d1a;
  --bg-card: rgba(26, 33, 29, 0.9);
  --text-primary: #edf1ed;
  --text-secondary: #99a39c;
  --accent-primary: #b8c7bd;
  --accent-secondary: #8fa095;
  --accent-danger: #c28f87;
  --accent-warning: #c7b59a;
  --border-color: rgba(208, 220, 211, 0.12);
  --shadow: 0 14px 34px rgba(0, 0, 0, 0.28);
  --shadow-lg: 0 28px 68px rgba(0, 0, 0, 0.36);
  --surface-strong: rgba(255, 255, 255, 0.04);
}

body {
  font-family: Inter, -apple-system, BlinkMacSystemFont, 'Segoe UI', 'PingFang SC', 'Microsoft YaHei', sans-serif;
  background:
    radial-gradient(circle at top left, rgba(124, 143, 132, 0.08), transparent 28%),
    linear-gradient(180deg, rgba(255, 255, 255, 0.5), transparent 22%),
    var(--bg-primary);
  letter-spacing: -0.01em;
}

.icon {
  width: 1.05rem;
  height: 1.05rem;
  display: inline-block;
  vertical-align: middle;
  flex-shrink: 0;
}

.app {
  padding-left: 72px;
}

.header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1.5rem;
  padding: clamp(1.2rem, 1rem + 1vw, 2rem) clamp(1.2rem, 1rem + 2vw, 2.5rem);
  background: rgba(250, 247, 241, 0.72);
  backdrop-filter: blur(18px);
  border-bottom: 1px solid var(--border-color);
  box-shadow: none;
}

.brand-lockup {
  display: flex;
  align-items: center;
  gap: 1rem;
  min-width: 0;
}

.brand-mark {
  width: 3rem;
  height: 3rem;
  border-radius: 1rem;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  background: linear-gradient(180deg, rgba(255,255,255,0.8), rgba(255,255,255,0.45));
  border: 1px solid var(--border-color);
  color: var(--accent-primary);
  box-shadow: inset 0 1px 0 rgba(255,255,255,0.65);
}

.brand-mark .icon {
  width: 1.25rem;
  height: 1.25rem;
}

.eyebrow {
  font-size: 0.75rem;
  letter-spacing: 0.18em;
  text-transform: uppercase;
  color: var(--text-secondary);
  margin-bottom: 0.2rem;
}

.header h1 {
  margin: 0;
  font-size: clamp(1.3rem, 1rem + 1.2vw, 1.8rem);
  color: var(--text-primary);
  font-weight: 600;
}

.header-stats {
  gap: 0.9rem;
  justify-content: flex-end;
}

.stat {
  display: inline-flex;
  align-items: center;
  gap: 0.7rem;
  padding: 0.78rem 0.95rem;
  border: 1px solid var(--border-color);
  border-radius: 999px;
  background: var(--surface-strong);
  color: var(--text-secondary);
  min-height: 48px;
}

.stat .icon {
  color: var(--accent-primary);
}

.stat strong {
  display: inline-block;
  margin-left: 0.3rem;
  color: var(--text-primary);
  font-size: 1rem;
}

.main {
  max-width: 1280px;
  padding: clamp(1.25rem, 1rem + 1.2vw, 2.4rem);
}

.welcome-card,
.quiz-card,
.modal-content,
.conj-controls,
.community-wordbook-card,
.word-item,
.stat-card,
.chart-container,
.feature-box,
.usage-box,
.conjugation-module-card,
.editor-word-item,
.wordbook-select-item,
.preview-meta,
.preview-word-item {
  background: var(--bg-card);
  backdrop-filter: blur(14px);
  border: 1px solid var(--border-color);
  box-shadow: var(--shadow);
}

.welcome-card {
  border-radius: 28px;
  padding: clamp(1.4rem, 1rem + 2vw, 3rem);
  box-shadow: var(--shadow-lg);
}

.vocab-section,
.custom-wordbook-section,
.community-wordbook-section,
.conjugation-module-section,
.mode-selection {
  margin-bottom: 0;
  padding-top: clamp(1.5rem, 1rem + 1.4vw, 2.4rem);
  border-top: 1px solid var(--border-color);
}

.vocab-section { padding-top: 0; border-top: 0; }

.welcome-card h2,
.vocab-section h2,
.custom-wordbook-section h2,
.community-wordbook-section h2,
.conjugation-module-section h2,
.mode-selection h2 {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 0.65rem;
  font-size: clamp(1.25rem, 1.05rem + 1vw, 1.8rem);
  font-weight: 600;
  color: var(--text-primary);
  margin-bottom: 0.5rem;
}

.welcome-card h2 .icon,
.mode-selection h2 .icon,
.community-wordbook-section h2 .icon,
.conjugation-module-section h2 .icon,
.vocab-section h2 .icon,
.custom-wordbook-section h2 .icon {
  width: 1.1rem;
  height: 1.1rem;
  color: var(--accent-primary);
}

.subtitle {
  max-width: 42rem;
  margin: 0 auto 1.75rem;
  font-size: 0.98rem;
  line-height: 1.7;
  color: var(--text-secondary);
}

.level-buttons,
.mode-buttons,
.community-buttons,
.wordbook-cards {
  gap: clamp(0.9rem, 0.8rem + 0.5vw, 1.25rem);
}

.level-buttons,
.wordbook-cards {
  grid-template-columns: repeat(auto-fit, minmax(210px, 1fr));
}

.mode-buttons {
  grid-template-columns: repeat(auto-fit, minmax(230px, 1fr));
}

.level-btn,
.mode-btn,
.community-buttons button,
.wordbook-card {
  justify-content: center;
  gap: 0.55rem;
  min-height: 156px;
  padding: 1.35rem 1.1rem;
  border: 1px solid var(--border-color);
  border-radius: 22px;
  background: linear-gradient(180deg, rgba(255,255,255,0.72), rgba(255,255,255,0.38));
  box-shadow: none;
}

.level-btn:hover,
.mode-btn:hover,
.community-buttons button:hover,
.wordbook-card:hover,
.community-wordbook-card:hover,
.wordbook-select-item:hover,
.option-btn:hover:not(.correct):not(.incorrect):not(:disabled) {
  transform: translateY(-2px);
  border-color: rgba(85, 107, 96, 0.3);
  box-shadow: var(--shadow);
}

.level-btn.selected,
.wordbook-card.selected {
  background: linear-gradient(180deg, rgba(85,107,96,0.95), rgba(75,94,84,0.95));
  color: #f7f5f0;
}

.level-btn.selected .level-count,
.wordbook-card.selected .wordbook-card-count,
.wordbook-card.selected .wordbook-card-date,
.level-btn.selected .level-name,
.wordbook-card.selected .wordbook-card-name {
  color: #f7f5f0;
}

.level-icon,
.mode-icon,
.sidebar-icon {
  display: inline-flex;
  align-items: center;
  justify-content: center;
}

.level-icon .icon,
.mode-icon .icon {
  width: 1.55rem;
  height: 1.55rem;
}

.level-name,
.mode-name,
.wordbook-card-name {
  font-size: 1.05rem;
  font-weight: 600;
}

.level-count,
.mode-desc,
.wordbook-card-count,
.wordbook-card-date {
  font-size: 0.88rem;
  color: var(--text-secondary);
}

.new-badge {
  display: inline-flex;
  align-items: center;
  gap: 0.35rem;
  padding: 0.28rem 0.6rem;
  border-radius: 999px;
  background: rgba(85, 107, 96, 0.1);
  color: var(--accent-primary);
  box-shadow: none;
  animation: none;
}

.new-badge .icon {
  width: 0.85rem;
  height: 0.85rem;
}

.quiz-container,
.browse-container {
  max-width: 980px;
}

.quiz-header,
.browse-header,
.conj-controls,
.editor-toolbar,
.modal-header,
.form-actions,
.wordbook-card-actions,
.preview-actions,
.community-buttons,
.conj-module-toolbar {
  gap: 0.9rem;
}

.quiz-card {
  border-radius: 28px;
  padding: clamp(1.4rem, 1rem + 2vw, 2.5rem);
}

.question-section {
  margin-bottom: 2rem;
}

.italian-word,
.english-word {
  font-size: clamp(2rem, 1.5rem + 2vw, 3rem);
  color: var(--text-primary);
  letter-spacing: -0.03em;
}

.question-label,
.options-label,
.conj-tense-line,
.conj-pronoun-line,
.conj-english-line,
.quiz-progress,
.quiz-score,
.conj-module-hint,
.import-hint-small,
.stat-label {
  color: var(--text-secondary);
}

.back-btn,
.next-btn,
.check-btn,
.hint-btn,
.pronunciation-btn,
.filter-btn,
.form-btn,
.editor-toolbar-btn,
.stats-tab-btn,
.wordbook-card-actions button,
.preview-download-btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.5rem;
  min-height: 44px;
  padding: 0.8rem 1.1rem;
  border-radius: 999px;
  border: 1px solid var(--border-color);
  font-weight: 600;
}

.back-btn,
.filter-btn,
.form-btn.cancel,
.stats-tab-btn,
.editor-action-btn,
.word-action-btn {
  background: var(--surface-strong);
  color: var(--text-primary);
}

.next-btn,
.check-btn,
.pronunciation-btn,
.form-btn.primary,
.preview-download-btn,
.wordbook-download-btn,
.wordbook-action-btn.download,
.editor-toolbar-btn,
.community-buttons button:hover,
.sidebar-btn:hover {
  background: var(--accent-primary);
  color: #f6f4ef;
  border-color: var(--accent-primary);
}

.hint-btn {
  background: rgba(85, 107, 96, 0.08);
  color: var(--accent-primary);
  border-color: rgba(85, 107, 96, 0.18);
}

.hint-btn:hover,
.back-btn:hover,
.filter-btn:hover,
.form-btn.cancel:hover,
.wordbook-preview-btn:hover,
.stats-tab-btn:hover,
.editor-action-btn:hover,
.word-action-btn:hover {
  background: rgba(85, 107, 96, 0.08);
  color: var(--text-primary);
  border-color: rgba(85, 107, 96, 0.2);
  transform: translateY(-1px);
}

.search-input,
.spelling-input,
.form-input,
.form-textarea,
.filter-select,
.conj-controls select,
.conj-module-toolbar select {
  min-height: 48px;
  border: 1px solid var(--border-color);
  border-radius: 18px;
  background: rgba(255,255,255,0.58);
  box-shadow: inset 0 1px 0 rgba(255,255,255,0.4);
}

.search-input:focus,
.spelling-input:focus,
.form-input:focus,
.form-textarea:focus,
.filter-select:focus,
.conj-controls select:focus,
.conj-module-toolbar select:focus {
  border-color: rgba(85, 107, 96, 0.35);
  box-shadow: 0 0 0 4px rgba(85, 107, 96, 0.08);
}

.options-grid,
.conj-full-grid,
.stats-grid,
.community-wordbook-list {
  gap: 1rem;
}

.option-btn,
.conj-full-item,
.word-item,
.preview-word-item,
.community-wordbook-card,
.stat-card {
  border-radius: 20px;
}

.option-btn {
  padding: 1.1rem 1.15rem;
  background: rgba(255,255,255,0.52);
  border: 1px solid var(--border-color);
}

.option-btn.correct,
.quiz-feedback.correct,
.conj-full-item.correct,
.word-item.mastered,
.mastered-badge {
  background: rgba(124, 143, 132, 0.12);
  color: var(--text-primary);
  border-color: rgba(124, 143, 132, 0.28);
}

.option-btn.incorrect,
.quiz-feedback.incorrect,
.conj-full-item.incorrect {
  background: rgba(142, 95, 88, 0.12);
  color: var(--text-primary);
  border-color: rgba(142, 95, 88, 0.25);
}

.quiz-feedback {
  border-radius: 22px;
  padding: 1.1rem 1.2rem;
}

.word-list,
.editor-word-list,
.preview-word-list {
  gap: 0.85rem;
  padding: 0.2rem;
}

.word-item {
  padding: 1rem 1.15rem;
  align-items: flex-start;
}

.word-item:hover {
  transform: none;
}

.word-italian,
.preview-word-italian,
.editor-word-italian {
  color: var(--text-primary);
}

.word-chinese,
.preview-word-chinese,
.editor-word-chinese,
.word-notes,
.quiz-notes {
  color: var(--text-secondary);
  background: rgba(85, 107, 96, 0.05);
  border-left-color: rgba(85, 107, 96, 0.25);
}

.sidebar {
  width: 72px;
  padding: 1rem 0.65rem;
  background: rgba(250, 247, 241, 0.78);
  backdrop-filter: blur(16px);
  border-right: 1px solid var(--border-color);
  box-shadow: none;
}

.sidebar:hover {
  width: 184px;
}

.sidebar-btn {
  border-radius: 16px;
  padding: 0.9rem 0.85rem;
}

.sidebar-icon {
  width: 24px;
  color: inherit;
}

.sidebar-icon .icon {
  width: 1.1rem;
  height: 1.1rem;
}

.modal {
  background: rgba(19, 24, 22, 0.26);
  backdrop-filter: blur(8px);
}

.modal-content {
  border-radius: 28px;
}

.modal-header,
.modal-body,
.editor-toolbar,
.stats-tab-content,
.help-modal-body {
  padding-left: clamp(1.1rem, 0.8rem + 1vw, 2rem);
  padding-right: clamp(1.1rem, 0.8rem + 1vw, 2rem);
}

.modal-header {
  padding-top: 1.25rem;
  padding-bottom: 1rem;
}

.modal-body,
.help-modal-body,
.stats-tab-content {
  padding-top: 1.1rem;
  padding-bottom: 1.35rem;
}

.close-btn {
  width: 40px;
  height: 40px;
  font-size: 1.5rem;
}

.stats-tabs {
  gap: 0.5rem;
  padding: 0.75rem;
  border-bottom: 1px solid var(--border-color);
  background: transparent;
}

.stats-tab-btn {
  border-radius: 999px;
  border-bottom: 0;
}

.stats-tab-btn.active {
  background: rgba(85, 107, 96, 0.1);
  color: var(--accent-primary);
  border-bottom-color: transparent;
}

.help-section h2,
.help-section h3,
.help-section h4,
.browse-screen-header h2,
.wordbook-card-title h3,
.preview-meta h3 {
  color: var(--text-primary);
}

.help-section h3,
.preview-word-list h4,
.stats-table th,
.modal-header,
.editor-toolbar,
.stats-table td,
.stat-item,
.conj-matrix-head,
.conj-matrix-row-label,
.conj-matrix-cell {
  border-color: var(--border-color);
}

.community-wordbook-card,
.wordbook-card,
.wordbook-select-item,
.editor-word-item,
.preview-word-item,
.tag-selector,
.tag-option,
.preview-word-list,
.stats-table-container,
.chart-container,
.stats-section,
.feature-box,
.usage-box,
.conj-matrix-head,
.conj-matrix-row-label,
.conj-matrix-cell {
  border-color: var(--border-color);
}

.wordbook-tag,
.tag-option,
.mastered-badge,
.wordbook-difficulty-badge {
  border-radius: 999px;
}

.wordbook-delete-btn,
.wordbook-card-manage-btn,
.editor-action-btn,
.word-action-btn {
  opacity: 1;
  width: 36px;
  height: 36px;
  border-radius: 999px;
  border: 1px solid var(--border-color);
}

.wordbook-delete-btn,
.editor-action-btn.delete {
  background: rgba(142, 95, 88, 0.1);
  color: var(--accent-danger);
}

.wordbook-card-manage-btn,
.editor-action-btn.edit,
.word-action-btn,
.preview-tags .wordbook-tag,
.tag-option:has(input:checked) {
  background: rgba(85, 107, 96, 0.08);
  color: var(--accent-primary);
  border-color: rgba(85, 107, 96, 0.15);
}

.loading {
  gap: 1.25rem;
}

.spinner {
  width: 44px;
  height: 44px;
  border-width: 3px;
  border-top-color: var(--accent-primary);
}

@media (max-width: 1024px) {
  .header {
    flex-direction: column;
    align-items: flex-start;
  }

  .header-stats {
    width: 100%;
    justify-content: flex-start;
  }

  .module-grid {
    grid-template-columns: 1fr 1fr;
  }
}

@media (max-width: 768px) {
  .app {
    padding-left: 0;
    padding-bottom: 72px;
  }

  .header {
  padding: 1.25rem;
    gap: 1rem;
  }

  .header-stats {
    display: grid;
    grid-template-columns: 1fr;
    width: 100%;
  }

  .header-center,
  .top-nav,
  .breadcrumb,
  .module-grid,
  .section-head-row,
  .inline-actions,
  .selection-summary-card {
    width: 100%;
  }

  .module-grid,
  .selection-summary-card {
    grid-template-columns: 1fr;
  }

  .top-nav,
  .section-head-row,
  .inline-actions {
    flex-direction: column;
    align-items: stretch;
  }

  .stat {
    width: 100%;
    border-radius: 18px;
  }

  .welcome-card,
  .quiz-card,
  .modal-content {
    border-radius: 22px;
  }

  .level-buttons,
  .wordbook-cards,
  .mode-buttons,
  .community-buttons,
  .community-wordbook-list,
  .stats-grid,
  .charts-row {
    grid-template-columns: 1fr;
  }

  .sidebar {
    top: auto;
    bottom: 0;
    left: 0;
    right: 0;
    width: 100% !important;
    height: 72px;
    flex-direction: row;
    padding: 0.55rem;
    border-right: 0;
    border-top: 1px solid var(--border-color);
  }

  .sidebar:hover {
    width: 100% !important;
    height: 72px;
  }

  .mobile-floating-back {
    display: inline-flex;
  }

  .sidebar-btn {
    flex: 1;
    min-width: 0;
    flex-direction: column;
    gap: 0.3rem;
    justify-content: center;
    padding: 0.5rem 0.2rem;
  }

  .sidebar-label,
  .sidebar:hover .sidebar-label {
    opacity: 1;
    font-size: 0.64rem;
  }

  .browse-header,
  .quiz-header,
  .conj-controls,
  .editor-toolbar,
  .form-actions,
  .preview-actions {
    flex-direction: column;
    align-items: stretch;
  }
}

@media (max-width: 640px) {
  /* Grammar setup toolbar: stack vertically */
  .conj-module-toolbar {
    flex-direction: column;
    align-items: stretch;
    gap: 0.75rem;
  }

  .conj-module-toolbar label {
    justify-content: space-between;
  }

  .conj-module-toolbar select {
    flex: 1;
    min-width: 0;
    width: 100%;
  }

  /* Lesson nav: stack prev/label/next vertically */
  .conj-lesson-nav {
    flex-direction: column;
    align-items: stretch;
    gap: 0.5rem;
  }

  .conj-lesson-status {
    min-width: 0;
    text-align: center;
  }

  /* Tense buttons in mobile layout: compact */
  .conj-tense-btn {
    min-height: 60px;
  }

  /* Mode buttons in conjugation setup: single column */
  #conjugationModeButtons {
    grid-template-columns: 1fr;
  }

  #conjugationModeButtons .mode-btn {
    min-height: 100px;
    flex-direction: row;
    justify-content: flex-start;
    text-align: left;
    gap: 1rem;
    padding: 1rem 1.1rem;
  }

  #conjugationModeButtons .mode-icon {
    flex-shrink: 0;
  }

  #conjugationModeButtons .mode-desc {
    text-align: left;
  }
}

@media (max-width: 480px) {
  .brand-mark {
    width: 2.6rem;
    height: 2.6rem;
  }

  .italian-word,
  .english-word {
    font-size: 1.8rem;
  }

  .level-btn,
  .mode-btn,
  .community-buttons button,
  .wordbook-card {
    min-height: 132px;
  }

  .mobile-floating-back {
    right: 0.85rem;
    left: auto;
    bottom: calc(84px + env(safe-area-inset-bottom, 0px));
    padding: 0.82rem 0.95rem;
  }
}

/* ============================================================
   GRAMMAR BOOK — 语法书阅读器
   ============================================================ */

.main:has(#grammarBookScreen.screen.active),
.main:has(#verbCollocationsScreen.screen.active) {
  display: flex;
  width: 100%;
  max-width: none;
  min-height: 0;
  padding: 0;
}

/* Override .screen defaults for the book layout */
#grammarBookScreen.screen,
#verbCollocationsScreen.screen {
  display: none;
}
#grammarBookScreen.screen.active,
#verbCollocationsScreen.screen.active {
  padding: 0;
  overflow: hidden;
  display: flex;
  flex-direction: column;
  flex: 1;
  min-height: 0;
  width: 100%;
}

/* Two-column layout: sidebar + content */
.grammar-book-layout {
  display: flex;
  flex-direction: row;
  height: 100%;
  width: 100%;
  overflow: hidden;
  background: var(--bg-primary, #fff);
}

/* ── Sidebar ── */
.grammar-nav-sidebar {
  width: 280px;
  min-width: 280px;
  display: flex;
  flex-direction: column;
  border-right: 1px solid var(--border-color, #e0e0e0);
  background: var(--bg-secondary, #f7f7f7);
  overflow: hidden;
  transition: width 0.25s ease, min-width 0.25s ease;
  flex-shrink: 0;
}

.grammar-nav-header {
  padding: 0.75rem 1rem;
  border-bottom: 1px solid var(--border-color, #e0e0e0);
  display: flex;
  flex-direction: column;
  gap: 0.4rem;
}

.grammar-book-back-btn {
  background: none;
  border: none;
  cursor: pointer;
  color: var(--accent-color, #4a6fa5);
  font-size: 0.85rem;
  padding: 0.25rem 0;
  text-align: left;
  opacity: 0.8;
}
.grammar-book-back-btn:hover { opacity: 1; text-decoration: underline; }

.grammar-nav-title {
  font-size: 1rem;
  font-weight: 700;
  color: var(--text-primary, #222);
  display: flex;
  align-items: center;
  gap: 0.4rem;
  margin: 0;
}

.grammar-nav-tree {
  flex: 1;
  overflow-y: auto;
  padding: 0.5rem 0;
}

/* ============================================================
   VERB COLLOCATIONS — 动词搭配阅读器
   ============================================================ */

.vc-search-panel {
  padding: 0.9rem 1rem 0.4rem;
  border-bottom: 1px solid var(--border-color, #e0e0e0);
}

.vc-search-label {
  display: block;
  font-size: 0.8rem;
  font-weight: 700;
  color: var(--text-primary);
  margin-bottom: 0.45rem;
}

.vc-search-input-wrap {
  position: relative;
}

.vc-search-icon {
  position: absolute;
  left: 0.9rem;
  top: 50%;
  transform: translateY(-50%);
  color: var(--text-secondary);
  pointer-events: none;
}

.vc-search-input {
  width: 100%;
  min-width: 0;
  padding-left: 2.8rem;
  border-radius: 14px;
}

.vc-search-help {
  margin-top: 0.55rem;
  font-size: 0.76rem;
  line-height: 1.45;
  color: var(--text-secondary);
}

.vc-search-matches {
  display: flex;
  flex-wrap: wrap;
  gap: 0.45rem;
  margin-top: 0.75rem;
}

.vc-search-match-btn {
  display: inline-flex;
  align-items: center;
  gap: 0.45rem;
  max-width: 100%;
  padding: 0.42rem 0.7rem;
  border-radius: 999px;
  border: 1px solid var(--border-color);
  background: var(--surface-strong);
  color: var(--text-primary);
  cursor: pointer;
  font-size: 0.76rem;
}

.vc-search-match-btn:hover,
.vc-search-match-btn.active {
  background: rgba(85, 107, 96, 0.1);
  border-color: rgba(85, 107, 96, 0.2);
}

.vc-search-match-name {
  font-weight: 600;
}

.vc-search-match-meta {
  color: var(--text-secondary);
}

.vc-preposition-tree {
  padding-top: 0.55rem;
}

.vc-prep-link {
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 0.75rem;
  width: 100%;
  padding: 0.7rem 1rem;
  background: none;
  border: none;
  border-left: 3px solid transparent;
  cursor: pointer;
  text-align: left;
  color: var(--text-primary);
}

.vc-prep-link:hover {
  background: var(--hover-bg, rgba(0,0,0,0.04));
}

.vc-prep-link.active {
  background: rgba(85, 107, 96, 0.08);
  border-left-color: var(--accent-primary);
}

.vc-prep-name {
  font-size: 0.95rem;
  font-weight: 700;
}

.vc-prep-count {
  font-size: 0.76rem;
  color: var(--text-secondary);
  white-space: nowrap;
}

.vc-panel-intro {
  margin-bottom: 1.35rem;
}

.vc-kicker {
  display: inline-block;
  margin-bottom: 0.45rem;
  font-size: 0.74rem;
  font-weight: 700;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--text-secondary);
}

.vc-panel-intro h2 {
  font-size: 1.65rem;
  line-height: 1.2;
  color: var(--text-primary);
  margin: 0 0 0.45rem;
}

.vc-panel-intro p {
  margin: 0;
  color: var(--text-secondary);
  font-size: 0.96rem;
}

.vc-card-grid,
.vc-search-choice-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: 1rem;
}

.vc-card {
  padding: 1.1rem 1.15rem;
  border: 1px solid var(--border-color);
  border-radius: 22px;
  background: var(--bg-card);
  box-shadow: var(--shadow);
}

.vc-card-header {
  display: flex;
  justify-content: space-between;
  align-items: flex-start;
  gap: 0.85rem;
  margin-bottom: 0.85rem;
}

.vc-card-title {
  margin: 0;
  font-size: 1.08rem;
  color: var(--text-primary);
}

.vc-card-subtitle {
  margin: 0.25rem 0 0;
  font-size: 0.82rem;
  color: var(--text-secondary);
}

.vc-card-badge {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 0.38rem 0.7rem;
  border-radius: 999px;
  background: rgba(85, 107, 96, 0.08);
  color: var(--accent-primary);
  font-size: 0.78rem;
  font-weight: 700;
  white-space: nowrap;
}

.vc-example-list {
  list-style: none;
  padding: 0;
  margin: 0;
  display: flex;
  flex-direction: column;
  gap: 0.65rem;
}

.vc-example-item {
  position: relative;
  padding-left: 1rem;
  color: var(--text-primary);
  line-height: 1.65;
  font-size: 0.94rem;
}

.vc-example-item::before {
  content: '•';
  position: absolute;
  left: 0;
  top: 0;
  color: var(--accent-primary);
}

.vc-search-choice-btn {
  display: flex;
  flex-direction: column;
  align-items: flex-start;
  gap: 0.25rem;
  padding: 1rem 1.05rem;
  border: 1px solid var(--border-color);
  border-radius: 18px;
  background: var(--bg-card);
  color: var(--text-primary);
  cursor: pointer;
  text-align: left;
  box-shadow: var(--shadow);
}

.vc-search-choice-btn:hover {
  transform: translateY(-2px);
  border-color: rgba(85, 107, 96, 0.2);
}

.vc-search-choice-name {
  font-size: 1rem;
  font-weight: 700;
}

.vc-search-choice-meta {
  font-size: 0.84rem;
  color: var(--text-secondary);
}

.vc-empty-state {
  min-height: 320px;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 0.7rem;
  text-align: center;
  color: var(--text-secondary);
}

.vc-empty-state h2 {
  margin: 0;
  font-size: 1.2rem;
  color: var(--text-primary);
}

.vc-empty-state p {
  margin: 0;
  max-width: 34rem;
}

.vc-empty-state-icon {
  width: 2rem;
  height: 2rem;
  opacity: 0.6;
}

/* ============================================================
   VERB COLLOCATION PRACTICE — 动词搭配练习
   ============================================================ */

.vc-practice-container {
  max-width: 960px;
}

.vc-practice-setup-card,
.vc-practice-container .quiz-card {
  display: flex;
  flex-direction: column;
  gap: 1.25rem;
}

.vc-practice-header {
  gap: 0.35rem;
}

.vc-practice-header h2 {
  display: flex;
  align-items: center;
  gap: 0.55rem;
  justify-content: flex-start;
  margin-bottom: 0;
}

.vc-practice-config-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1rem;
}

.vc-practice-config-block {
  display: flex;
  flex-direction: column;
  gap: 0.5rem;
}

.vc-practice-label {
  font-size: 0.88rem;
  color: var(--text-secondary);
  font-weight: 600;
}

.vc-practice-summary {
  grid-template-columns: repeat(3, minmax(0, 1fr));
}

.vc-practice-actions {
  justify-content: flex-start;
  margin-top: 0;
}

.vc-practice-prompt {
  white-space: pre-wrap;
}

.vc-practice-subprompt {
  margin-top: 0.75rem;
  font-size: 1rem;
  color: var(--text-secondary);
  line-height: 1.7;
}

.vc-practice-hint {
  margin-top: 0.6rem;
}

.vc-translation-grid {
  width: 100%;
  display: flex;
  flex-wrap: wrap;
  gap: 0.85rem;
  justify-content: center;
}

.vc-translation-token {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 0.35rem;
  min-width: 88px;
}

.vc-translation-input {
  width: 100%;
  min-width: 88px;
  padding: 0.7rem 0.75rem;
  border: 1px solid var(--border-color);
  border-radius: 12px;
  background: rgba(255,255,255,0.58);
  color: var(--text-primary);
  text-align: center;
  font-size: 1rem;
}

.vc-translation-placeholder {
  font-family: 'Courier New', monospace;
  font-size: 0.92rem;
  color: var(--text-secondary);
  letter-spacing: 0.05em;
}

.vc-translation-token.correct .vc-translation-input,
.vc-translation-token.revealed .vc-translation-input {
  border-color: rgba(124, 143, 132, 0.45);
  background: rgba(124, 143, 132, 0.12);
}

.vc-translation-token.incorrect .vc-translation-input {
  border-color: rgba(142, 95, 88, 0.45);
  background: rgba(142, 95, 88, 0.12);
}

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

/* Part headings */
.grammar-part-heading {
  font-size: 0.7rem;
  font-weight: 700;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  color: var(--text-secondary, #888);
  padding: 0.9rem 1rem 0.3rem;
}

/* Chapter */
.grammar-chapter {
  margin-bottom: 0.1rem;
}

.grammar-chapter-btn {
  display: flex;
  align-items: flex-start;
  gap: 0.4rem;
  width: 100%;
  background: none;
  border: none;
  cursor: pointer;
  padding: 0.45rem 1rem;
  text-align: left;
  font-size: 0.82rem;
  color: var(--text-primary, #222);
  line-height: 1.35;
}
.grammar-chapter-btn:hover {
  background: var(--hover-bg, rgba(0,0,0,0.05));
}

.grammar-chapter-arrow {
  font-size: 0.6rem;
  margin-top: 0.2rem;
  flex-shrink: 0;
  transition: transform 0.2s ease;
  color: var(--text-secondary, #999);
}
.grammar-chapter-btn.open .grammar-chapter-arrow {
  transform: rotate(90deg);
}

.grammar-chapter-label {
  flex: 1;
}

/* Topic list (collapsible) */
.grammar-topic-list {
  overflow: hidden;
  max-height: 2000px;
  transition: max-height 0.25s ease;
}
.grammar-topic-list.collapsed {
  max-height: 0;
}

/* Topic links */
.grammar-topic-link {
  display: block;
  width: 100%;
  background: none;
  border: none;
  cursor: pointer;
  padding: 0.35rem 1rem 0.35rem 2rem;
  text-align: left;
  font-size: 0.8rem;
  color: var(--text-secondary, #555);
  line-height: 1.4;
}
.grammar-topic-link:hover {
  background: var(--hover-bg, rgba(0,0,0,0.04));
  color: var(--text-primary, #222);
}
.grammar-topic-link.active {
  background: var(--accent-light, rgba(74,111,165,0.12));
  color: var(--accent-color, #4a6fa5);
  font-weight: 600;
  border-right: 3px solid var(--accent-color, #4a6fa5);
}

/* ── Content area ── */
.grammar-content-area {
  flex: 1;
  display: flex;
  flex-direction: column;
  overflow: hidden;
  min-width: 0;
}

.grammar-content-header {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  padding: 0.6rem 1.25rem;
  border-bottom: 1px solid var(--border-color, #e0e0e0);
  background: var(--bg-primary, #fff);
  flex-shrink: 0;
}

.grammar-sidebar-toggle {
  background: none;
  border: 1px solid var(--border-color, #ddd);
  border-radius: 6px;
  cursor: pointer;
  padding: 0.35rem;
  display: flex;
  align-items: center;
  color: var(--text-secondary, #666);
  flex-shrink: 0;
}
.grammar-sidebar-toggle:hover {
  background: var(--hover-bg, rgba(0,0,0,0.05));
}
.grammar-sidebar-toggle .icon {
  width: 18px;
  height: 18px;
  stroke: currentColor;
  fill: none;
  stroke-width: 2;
  stroke-linecap: round;
}

.grammar-content-breadcrumb {
  font-size: 0.82rem;
  color: var(--text-secondary, #777);
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}

.grammar-content-body {
  flex: 1;
  overflow-y: auto;
  padding: 1.5rem 2rem 3rem;
}

/* Welcome state */
.grammar-welcome {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  height: 100%;
  min-height: 300px;
  text-align: center;
  color: var(--text-secondary, #999);
  gap: 0.75rem;
}
.grammar-welcome-icon {
  width: 3rem;
  height: 3rem;
  opacity: 0.4;
}
.grammar-welcome h2 {
  font-size: 1.4rem;
  margin: 0;
}
.grammar-welcome p {
  font-size: 0.9rem;
  margin: 0;
}

/* Loading / error states */
.grammar-loading,
.grammar-error,
.grammar-nav-error,
.grammar-nav-loading {
  padding: 1rem 1.25rem;
  font-size: 0.85rem;
  color: var(--text-secondary, #888);
}
.grammar-error,
.grammar-nav-error {
  color: #c0392b;
}

/* ── Markdown content styles ── */
.grammar-markdown {
  max-width: 780px;
  line-height: 1.75;
  color: var(--text-primary, #222);
  font-size: 0.95rem;
}

.grammar-markdown h1,
.grammar-markdown h2,
.grammar-markdown h3,
.grammar-markdown h4,
.grammar-markdown h5,
.grammar-markdown h6 {
  margin: 1.6em 0 0.5em;
  line-height: 1.3;
  color: var(--text-primary, #111);
  font-weight: 700;
}
.grammar-markdown h1 { font-size: 1.6rem; }
.grammar-markdown h2 { font-size: 1.3rem; border-bottom: 1px solid var(--border-color, #eee); padding-bottom: 0.3em; }
.grammar-markdown h3 { font-size: 1.1rem; }
.grammar-markdown h4 { font-size: 1rem; }

.grammar-markdown p { margin: 0.6em 0 0.9em; }

.grammar-markdown ul,
.grammar-markdown ol {
  padding-left: 1.5rem;
  margin: 0.5em 0 0.9em;
}
.grammar-markdown li { margin-bottom: 0.25em; }

.grammar-markdown table {
  border-collapse: collapse;
  width: 100%;
  margin: 1em 0;
  font-size: 0.9rem;
}
.grammar-markdown th,
.grammar-markdown td {
  border: 1px solid var(--border-color, #ddd);
  padding: 0.5rem 0.75rem;
  text-align: left;
}
.grammar-markdown th {
  background: var(--bg-secondary, #f2f2f2);
  font-weight: 600;
}
.grammar-markdown tr:nth-child(even) td {
  background: var(--bg-secondary, #fafafa);
}

.grammar-markdown code {
  background: var(--bg-secondary, #f0f0f0);
  border-radius: 4px;
  padding: 0.1em 0.35em;
  font-family: 'Courier New', monospace;
  font-size: 0.88em;
}
.grammar-markdown pre {
  background: var(--bg-secondary, #f0f0f0);
  border-radius: 6px;
  padding: 1em;
  overflow-x: auto;
  margin: 0.75em 0;
}
.grammar-markdown pre code {
  background: none;
  padding: 0;
}

.grammar-markdown blockquote {
  border-left: 4px solid var(--accent-color, #4a6fa5);
  margin: 0.75em 0;
  padding: 0.4em 1em;
  background: var(--accent-light, rgba(74,111,165,0.07));
  color: var(--text-secondary, #555);
  border-radius: 0 4px 4px 0;
}

.grammar-markdown hr {
  border: none;
  border-top: 1px solid var(--border-color, #ddd);
  margin: 1.5em 0;
}

.grammar-markdown strong { font-weight: 700; }
.grammar-markdown em { font-style: italic; }

/* ── Sidebar collapsed state ── */
.grammar-book-layout.sidebar-collapsed .grammar-nav-sidebar {
  width: 0;
  min-width: 0;
}

/* ── Dark theme ── */
[data-theme="dark"] .grammar-nav-sidebar {
  background: var(--bg-secondary, #1e1e1e);
  border-right-color: var(--border-color, #333);
}
[data-theme="dark"] .grammar-content-header {
  background: var(--bg-primary, #121212);
  border-bottom-color: var(--border-color, #333);
}
[data-theme="dark"] .grammar-book-layout {
  background: var(--bg-primary, #121212);
}
[data-theme="dark"] .grammar-markdown th {
  background: var(--bg-secondary, #1e1e1e);
}
[data-theme="dark"] .grammar-markdown tr:nth-child(even) td {
  background: var(--bg-secondary, #1a1a1a);
}
[data-theme="dark"] .grammar-markdown code,
[data-theme="dark"] .grammar-markdown pre {
  background: #1e1e1e;
}

/* ── Responsive / Mobile ── */
@media (max-width: 768px) {
  #grammarBookScreen.screen {
    position: relative;
  }

  #verbCollocationsScreen.screen {
    position: relative;
  }

  .grammar-nav-sidebar {
    position: absolute;
    top: 0;
    bottom: 0;
    left: 0;
    height: auto;
    z-index: 100;
    box-shadow: 2px 0 12px rgba(0,0,0,0.15);
    width: 0;
    min-width: 0;
  }

  .grammar-book-layout.sidebar-open .grammar-nav-sidebar {
    width: 82vw;
    min-width: 260px;
    max-width: 320px;
  }

  .grammar-content-body {
    padding: 1rem 1rem 3rem;
  }

  .vc-search-panel {
    padding: 0.85rem 0.85rem 0.35rem;
  }

  .vc-card-grid,
  .vc-search-choice-grid {
    grid-template-columns: 1fr;
  }

  .vc-card-header {
    flex-direction: column;
    align-items: flex-start;
  }
}