/* ==========================================================================
   美丽中国·版图小达人 - 刷题 App 核心样式表
   Design: 清新绿意、少儿护眼、触屏大按钮、高对比度清晰排版、响应式适配
   ========================================================================== */

:root {
  --primary: #059669;
  --primary-hover: #047857;
  --primary-light: #ecfdf5;
  --primary-border: #a7f3d0;
  --accent: #0284c7;
  --accent-light: #e0f2fe;
  --success: #10b981;
  --success-bg: #d1fae5;
  --danger: #ef4444;
  --danger-bg: #fee2e2;
  --warning: #f59e0b;
  --warning-bg: #fef3c7;
  --bg-main: #f8fafc;
  --card-bg: #ffffff;
  --text-main: #1e293b;
  --text-muted: #64748b;
  --border-color: #e2e8f0;
  --shadow-sm: 0 1px 2px 0 rgb(0 0 0 / 0.05);
  --shadow: 0 4px 6px -1px rgb(0 0 0 / 0.08), 0 2px 4px -2px rgb(0 0 0 / 0.08);
  --shadow-lg: 0 10px 15px -3px rgb(0 0 0 / 0.1), 0 4px 6px -4px rgb(0 0 0 / 0.1);
  --radius-sm: 8px;
  --radius-md: 12px;
  --radius-lg: 18px;
  --font-family: -apple-system, BlinkMacSystemFont, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", "Segoe UI", Roboto, sans-serif;
}

[data-theme="dark"] {
  --primary: #10b981;
  --primary-hover: #059669;
  --primary-light: #064e3b;
  --primary-border: #047857;
  --accent: #38bdf8;
  --accent-light: #0c4a6e;
  --success: #34d399;
  --success-bg: #064e3b;
  --danger: #f87171;
  --danger-bg: #7f1d1d;
  --warning: #fbbf24;
  --warning-bg: #78350f;
  --bg-main: #0f172a;
  --card-bg: #1e293b;
  --text-main: #f1f5f9;
  --text-muted: #94a3b8;
  --border-color: #334155;
  --shadow-sm: 0 1px 2px 0 rgb(0 0 0 / 0.3);
  --shadow: 0 4px 6px -1px rgb(0 0 0 / 0.3);
  --shadow-lg: 0 10px 15px -3px rgb(0 0 0 / 0.4);
}

* {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
  -webkit-tap-highlight-color: transparent;
}

body {
  font-family: var(--font-family);
  background-color: var(--bg-main);
  color: var(--text-main);
  line-height: 1.6;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  transition: background-color 0.25s ease, color 0.25s ease;
}

/* ========================================================
   顶部导航栏（支持 桌面 / 平板 / 手机 全端响应式）
   ======================================================== */
.navbar {
  background: var(--card-bg);
  border-bottom: 1px solid var(--border-color);
  position: sticky;
  top: 0;
  z-index: 40;
  box-shadow: var(--shadow-sm);
  transition: all 0.25s ease;
}

/* 品牌 Logo 区域 */
.nav-brand {
  display: flex;
  align-items: center;
  gap: 10px;
  cursor: pointer;
  user-select: none;
  min-width: 0;
  flex-shrink: 0;
}

.nav-logo-icon {
  width: 38px;
  height: 38px;
  min-width: 38px;
  background: linear-gradient(135deg, #059669, #0284c7);
  border-radius: var(--radius-sm);
  display: flex;
  align-items: center;
  justify-content: center;
  color: #fff;
  font-size: 20px;
  box-shadow: 0 2px 5px rgba(5, 150, 105, 0.3);
  flex-shrink: 0;
}

.nav-brand-text {
  min-width: 0;
}

.nav-title {
  font-size: 1.15rem;
  font-weight: 700;
  color: var(--text-main);
  letter-spacing: 0.5px;
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}

.nav-subtitle {
  font-size: 0.74rem;
  color: var(--text-muted);
  font-weight: normal;
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}

/* 右侧快捷工具图标组 */
.nav-quick-actions {
  display: flex;
  align-items: center;
  gap: 8px;
}

.icon-btn {
  background: var(--bg-main);
  border: 1px solid var(--border-color);
  color: var(--text-main);
  width: 36px;
  height: 36px;
  min-width: 36px;
  border-radius: 50%;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  cursor: pointer;
  font-size: 17px;
  transition: all 0.2s ease;
  flex-shrink: 0;
}

.icon-btn:hover {
  background: var(--primary-light);
  border-color: var(--primary-border);
  color: var(--primary);
  transform: translateY(-1px);
}

.icon-btn.active {
  background: var(--primary);
  color: #ffffff;
  border-color: var(--primary);
}

/* 用户状态胶囊栏 (孩子、云同步、做题模式) */
.nav-status-bar {
  display: flex;
  align-items: center;
  gap: 8px;
}

.child-chip-btn {
  width: auto !important;
  height: 34px !important;
  padding: 0 12px !important;
  border-radius: 17px !important;
  display: inline-flex !important;
  align-items: center !important;
  gap: 5px;
  background: var(--primary-light) !important;
  border-color: var(--primary-border) !important;
  color: var(--primary) !important;
  font-size: 0.86rem !important;
  font-weight: 700;
  white-space: nowrap !important;
  flex-shrink: 0 !important;
}

.child-chip-btn .chip-arrow {
  font-size: 10px;
  opacity: 0.7;
}

.sync-badge-btn {
  width: auto !important;
  height: 34px !important;
  padding: 0 10px !important;
  border-radius: 17px !important;
  display: inline-flex !important;
  align-items: center !important;
  gap: 4px;
  font-size: 0.8rem !important;
  font-weight: 600;
  color: var(--text-muted);
  white-space: nowrap !important;
  flex-shrink: 0 !important;
}

.study-mode-btn {
  width: auto !important;
  height: 34px !important;
  padding: 0 12px !important;
  border-radius: 17px !important;
  font-size: 0.84rem !important;
  font-weight: 600 !important;
  display: inline-flex !important;
  align-items: center !important;
  white-space: nowrap !important;
  flex-shrink: 0 !important;
}

/* 桌面端布局 (>= 920px)：一行整齐排开 */
@media (min-width: 920px) {
  .navbar {
    padding: 10px 24px;
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 16px;
  }
  .nav-brand {
    order: 1;
  }
  .nav-status-bar {
    order: 2;
    margin-left: auto;
  }
  .nav-quick-actions {
    order: 3;
  }
}

/* 手机和平板端布局 (< 920px)：响应式两层分明结构，绝不垂直挤压 */
@media (max-width: 919px) {
  .navbar {
    display: grid;
    grid-template-columns: 1fr auto;
    grid-template-rows: auto auto;
    grid-template-areas:
      "brand quick"
      "status status";
    gap: 8px 10px;
    padding: 10px 14px;
  }
  .nav-brand {
    grid-area: brand;
    min-width: 0;
  }
  .nav-quick-actions {
    grid-area: quick;
    gap: 6px;
  }
  .nav-quick-actions .icon-btn {
    width: 34px;
    height: 34px;
    min-width: 34px;
    font-size: 16px;
  }
  .nav-status-bar {
    grid-area: status;
    display: flex;
    align-items: center;
    gap: 8px;
    width: 100%;
    overflow-x: auto;
    -webkit-overflow-scrolling: touch;
    scrollbar-width: none;
    padding-bottom: 2px;
  }
  .nav-status-bar::-webkit-scrollbar {
    display: none;
  }
}

/* 手机端精细化排版 (< 640px) */
@media (max-width: 640px) {
  .navbar {
    padding: 8px 12px;
    gap: 8px;
  }
  .nav-title {
    font-size: 0.98rem;
    letter-spacing: 0;
  }
  .nav-subtitle {
    display: none;
  }
  .nav-logo-icon {
    width: 32px;
    height: 32px;
    min-width: 32px;
    font-size: 17px;
  }
  .nav-quick-actions {
    gap: 5px;
  }
  .nav-quick-actions .icon-btn {
    width: 32px;
    height: 32px;
    min-width: 32px;
    font-size: 15px;
  }
  .child-chip-btn {
    height: 32px !important;
    padding: 0 10px !important;
    font-size: 0.82rem !important;
  }
  .sync-badge-btn {
    height: 32px !important;
    padding: 0 8px !important;
    font-size: 0.78rem !important;
  }
  .study-mode-btn {
    height: 32px !important;
    padding: 0 10px !important;
    font-size: 0.8rem !important;
  }
  .bank-select-wrapper {
    flex-direction: column !important;
    align-items: stretch !important;
    gap: 6px !important;
  }
  .bank-select-label {
    font-size: 0.84rem;
  }
  .custom-select {
    width: 100% !important;
    padding: 9px 12px;
    font-size: 0.88rem;
  }
  .control-bar {
    padding: 10px 12px;
    gap: 10px;
  }
  .pill-btn {
    padding: 6px 12px;
    font-size: 0.82rem;
  }
}

/* 超窄屏手机 (< 380px 如 iPhone SE) */
@media (max-width: 380px) {
  .navbar {
    padding: 6px 10px;
  }
  .nav-title {
    font-size: 0.92rem;
  }
  .nav-logo-icon {
    width: 28px;
    height: 28px;
    min-width: 28px;
    font-size: 15px;
  }
  .nav-quick-actions {
    gap: 4px;
  }
  .nav-quick-actions .icon-btn {
    width: 30px;
    height: 30px;
    min-width: 30px;
    font-size: 14px;
  }
  .nav-status-bar {
    gap: 6px;
  }
}

/* 主内容容器 */
.app-container {
  max-width: 900px;
  width: 100%;
  margin: 0 auto;
  padding: 16px;
  flex: 1;
  display: flex;
  flex-direction: column;
  gap: 16px;
}

/* 控制条：题库选择与刷题模式 */
.control-bar {
  background: var(--card-bg);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  padding: 12px 18px;
  display: flex;
  flex-direction: column;
  gap: 12px;
  box-shadow: var(--shadow-sm);
}

.bank-select-wrapper {
  display: flex;
  align-items: center;
  gap: 10px;
  width: 100%;
}

.bank-select-label {
  font-size: 0.92rem;
  font-weight: 700;
  color: var(--text-muted);
  white-space: nowrap;
  flex-shrink: 0;
  display: flex;
  align-items: center;
  gap: 4px;
}

.custom-select-container {
  flex: 1;
  min-width: 0;
  width: 100%;
}

.custom-select {
  width: 100%;
  background: var(--bg-main);
  border: 1px solid var(--border-color);
  color: var(--text-main);
  padding: 8px 12px;
  font-size: 0.94rem;
  font-weight: 600;
  border-radius: var(--radius-sm);
  cursor: pointer;
  outline: none;
  transition: border-color 0.2s, box-shadow 0.2s;
  text-overflow: ellipsis;
  overflow: hidden;
  white-space: nowrap;
}

.custom-select:focus {
  border-color: var(--primary);
  box-shadow: 0 0 0 2px var(--primary-light);
}

/* 模式药丸按钮栏（手机端可横向顺滑滑动，平板与电脑平铺） */
.mode-pills-wrapper {
  width: 100%;
  overflow-x: auto;
  -webkit-overflow-scrolling: touch;
  scrollbar-width: none;
}

.mode-pills-wrapper::-webkit-scrollbar {
  display: none;
}

.mode-pills {
  display: flex;
  gap: 8px;
  flex-wrap: nowrap;
}

@media (min-width: 768px) {
  .mode-pills {
    flex-wrap: wrap;
  }
}

.pill-btn {
  background: var(--bg-main);
  border: 1px solid var(--border-color);
  color: var(--text-muted);
  padding: 7px 14px;
  border-radius: 20px;
  font-size: 0.85rem;
  font-weight: 600;
  cursor: pointer;
  display: inline-flex;
  align-items: center;
  gap: 5px;
  transition: all 0.2s;
  white-space: nowrap;
  flex-shrink: 0;
}

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

.pill-btn.active {
  background: var(--primary);
  color: #fff;
  border-color: var(--primary);
  box-shadow: 0 2px 4px rgba(5, 150, 105, 0.25);
}

/* 刷题进度面板 */
.progress-panel {
  display: flex;
  align-items: center;
  justify-content: space-between;
  font-size: 0.88rem;
  color: var(--text-muted);
  gap: 12px;
}

.progress-track {
  flex: 1;
  height: 8px;
  background: var(--border-color);
  border-radius: 4px;
  overflow: hidden;
  position: relative;
}

.progress-fill {
  height: 100%;
  background: linear-gradient(90deg, var(--primary), var(--accent));
  width: 0%;
  border-radius: 4px;
  transition: width 0.3s ease;
}

.stats-badges {
  display: flex;
  align-items: center;
  gap: 10px;
  font-weight: 600;
}

.badge-tag {
  display: inline-flex;
  align-items: center;
  gap: 4px;
  padding: 3px 8px;
  border-radius: 6px;
  font-size: 0.8rem;
}

.badge-tag.correct {
  background: var(--success-bg);
  color: var(--success);
}

.badge-tag.wrong {
  background: var(--danger-bg);
  color: var(--danger);
}

.badge-tag.score {
  background: var(--warning-bg);
  color: var(--warning);
}

/* 核心题目卡片 */
.question-card {
  background: var(--card-bg);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-lg);
  padding: 24px 28px;
  box-shadow: var(--shadow);
  display: flex;
  flex-direction: column;
  gap: 20px;
  position: relative;
  transition: box-shadow 0.2s;
}

.q-meta-row {
  display: flex;
  align-items: center;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 8px;
  border-bottom: 1px solid var(--border-color);
  padding-bottom: 12px;
}

.q-tags {
  display: flex;
  align-items: center;
  gap: 6px;
  flex-wrap: wrap;
}

.q-type-badge {
  background: var(--primary-light);
  color: var(--primary);
  font-size: 0.78rem;
  font-weight: 700;
  padding: 3px 8px;
  border-radius: 4px;
  border: 1px solid var(--primary-border);
}

.q-source-badge {
  background: var(--bg-main);
  color: var(--text-muted);
  font-size: 0.75rem;
  padding: 3px 8px;
  border-radius: 4px;
  border: 1px solid var(--border-color);
}

.q-hot-badge {
  background: #fff1f2;
  color: #e11d48;
  border: 1px solid #fecdd3;
  font-size: 0.75rem;
  font-weight: 700;
  padding: 3px 8px;
  border-radius: 4px;
}

.q-fav-toggle {
  background: none;
  border: none;
  color: var(--text-muted);
  cursor: pointer;
  font-size: 20px;
  padding: 4px;
  transition: transform 0.2s, color 0.2s;
}

.q-fav-toggle:hover {
  transform: scale(1.15);
}

.q-fav-toggle.starred {
  color: #eab308;
}

.q-title {
  font-size: 1.18rem;
  font-weight: 600;
  color: var(--text-main);
  line-height: 1.65;
}

/* 题目图片展示 */
.q-images-gallery {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  justify-content: center;
  margin: 6px 0;
}

.q-img-wrap {
  position: relative;
  max-width: 100%;
  border-radius: var(--radius-md);
  overflow: hidden;
  border: 2px solid var(--border-color);
  cursor: pointer;
  transition: transform 0.2s, box-shadow 0.2s;
  background: #f1f5f9;
}

.q-img-wrap:hover {
  transform: scale(1.02);
  box-shadow: var(--shadow);
  border-color: var(--primary);
}

.q-img {
  max-height: 320px;
  max-width: 100%;
  display: block;
  object-fit: contain;
}

.q-img-zoom-tip {
  position: absolute;
  bottom: 8px;
  right: 8px;
  background: rgba(0, 0, 0, 0.65);
  color: #ffffff;
  font-size: 0.72rem;
  padding: 3px 8px;
  border-radius: 4px;
  backdrop-filter: blur(2px);
  pointer-events: none;
}

/* 选项列表 */
.options-list {
  display: flex;
  flex-direction: column;
  gap: 12px;
}

.option-item {
  background: var(--bg-main);
  border: 2px solid var(--border-color);
  border-radius: var(--radius-md);
  padding: 14px 18px;
  font-size: 1.02rem;
  font-weight: 500;
  display: flex;
  align-items: center;
  gap: 14px;
  cursor: pointer;
  transition: all 0.2s ease;
  user-select: none;
  min-height: 54px;
}

.option-item:hover {
  border-color: var(--primary);
  background: var(--primary-light);
  transform: translateX(4px);
}

.opt-letter {
  width: 32px;
  height: 32px;
  background: var(--card-bg);
  border: 1px solid var(--border-color);
  color: var(--text-muted);
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: 700;
  font-size: 0.95rem;
  flex-shrink: 0;
  transition: all 0.2s;
}

.opt-text {
  flex: 1;
  word-break: break-word;
}

/* 选项状态 */
.option-item.selected {
  border-color: var(--primary);
  background: var(--primary-light);
  color: var(--primary);
}

.option-item.selected .opt-letter {
  background: var(--primary);
  color: #fff;
  border-color: var(--primary);
}

.option-item.correct {
  border-color: var(--success) !important;
  background: var(--success-bg) !important;
  color: #065f46 !important;
}

.option-item.correct .opt-letter {
  background: var(--success) !important;
  color: #ffffff !important;
  border-color: var(--success) !important;
}

.option-item.wrong {
  border-color: var(--danger) !important;
  background: var(--danger-bg) !important;
  color: #991b1b !important;
}

.option-item.wrong .opt-letter {
  background: var(--danger) !important;
  color: #ffffff !important;
  border-color: var(--danger) !important;
}

.option-item.disabled {
  cursor: default;
  pointer-events: none;
}

/* 多选题确认按钮 */
.multi-submit-btn {
  background: linear-gradient(135deg, var(--primary), var(--accent));
  color: #fff;
  border: none;
  padding: 12px 24px;
  border-radius: var(--radius-md);
  font-size: 1rem;
  font-weight: 700;
  cursor: pointer;
  align-self: flex-start;
  transition: transform 0.2s, box-shadow 0.2s;
  box-shadow: 0 4px 10px rgba(5, 150, 105, 0.3);
}

.multi-submit-btn:hover {
  transform: translateY(-2px);
  box-shadow: 0 6px 14px rgba(5, 150, 105, 0.4);
}

/* 结果与解析面板 */
.result-banner {
  border-radius: var(--radius-md);
  padding: 16px 20px;
  display: flex;
  flex-direction: column;
  gap: 8px;
  animation: slideDown 0.25s ease-out;
}

.result-banner.correct {
  background: var(--success-bg);
  border: 1px solid #a7f3d0;
  color: #065f46;
}

.result-banner.wrong {
  background: var(--danger-bg);
  border: 1px solid #fecaca;
  color: #991b1b;
}

.result-header {
  display: flex;
  align-items: center;
  gap: 10px;
  font-size: 1.05rem;
  font-weight: 700;
}

.mode-label-short {
  display: none;
}

.result-explanation {
  font-size: 0.92rem;
  line-height: 1.6;
  opacity: 0.95;
}

/* 底部操作导航栏 */
.bottom-nav {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
  margin-top: 8px;
}

.navigation-caption {
  display: none;
}

.nav-btn {
  background: var(--card-bg);
  border: 1px solid var(--border-color);
  color: var(--text-main);
  padding: 12px 22px;
  border-radius: var(--radius-md);
  font-size: 0.98rem;
  font-weight: 600;
  cursor: pointer;
  display: inline-flex;
  align-items: center;
  gap: 8px;
  box-shadow: var(--shadow-sm);
  transition: all 0.2s;
}

.nav-btn:hover:not(:disabled) {
  background: var(--primary-light);
  border-color: var(--primary);
  color: var(--primary);
  transform: translateY(-1px);
}

.nav-btn:disabled {
  opacity: 0.5;
  cursor: not-allowed;
}

.nav-btn.primary {
  background: var(--primary);
  color: #ffffff;
  border-color: var(--primary);
}

.nav-btn.primary:hover:not(:disabled) {
  background: var(--primary-hover);
  color: #ffffff;
}

/* 答题卡抽屉/模态框 */
.modal-overlay {
  position: fixed;
  inset: 0;
  background: rgba(0, 0, 0, 0.55);
  backdrop-filter: blur(4px);
  z-index: 100;
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 16px;
  opacity: 0;
  visibility: hidden;
  pointer-events: none;
  transition: opacity 0.25s ease, visibility 0.25s ease;
}

.modal-overlay.active {
  opacity: 1;
  visibility: visible;
  pointer-events: auto;
}

/* 孩子切换按钮与云同步状态胶囊 */
.child-chip-btn {
  width: auto !important;
  padding: 0 12px !important;
  border-radius: 20px !important;
  display: inline-flex !important;
  align-items: center !important;
  gap: 4px;
  background: var(--primary-light) !important;
  border-color: var(--primary-border) !important;
  color: var(--primary) !important;
  font-weight: 700;
}

.child-chip-btn:hover {
  transform: translateY(-1px);
  box-shadow: 0 2px 6px rgba(5, 150, 105, 0.2);
}

.sync-badge-btn {
  width: auto !important;
  padding: 0 10px !important;
  border-radius: 20px !important;
  display: inline-flex !important;
  align-items: center !important;
  gap: 4px;
  font-size: 0.8rem !important;
  color: var(--text-muted);
}

.sync-badge-btn.syncing {
  color: var(--accent);
  border-color: var(--accent);
  background: var(--accent-light);
}

.sync-badge-btn.error {
  color: var(--danger);
  border-color: var(--danger);
  background: var(--danger-bg);
}

.sync-badge-btn.success {
  color: var(--success);
  border-color: var(--primary-border);
}

/* 孩子档案卡片列表 */
.children-card-list {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(220px, 1fr));
  gap: 12px;
  margin-bottom: 20px;
}

.child-profile-card {
  background: var(--bg-main);
  border: 2px solid var(--border-color);
  border-radius: var(--radius-md);
  padding: 14px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  cursor: pointer;
  transition: all 0.2s;
}

.child-profile-card:hover {
  border-color: var(--primary);
  transform: translateY(-2px);
}

.child-profile-card.active {
  border-color: var(--primary);
  background: var(--primary-light);
  box-shadow: 0 2px 8px rgba(5, 150, 105, 0.2);
}

.child-card-left {
  display: flex;
  align-items: center;
  gap: 12px;
}

.child-avatar-circle {
  width: 44px;
  height: 44px;
  border-radius: 50%;
  background: var(--card-bg);
  border: 1px solid var(--border-color);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 22px;
  box-shadow: var(--shadow-sm);
}

.child-info-name {
  font-weight: 700;
  font-size: 1.05rem;
  color: var(--text-main);
}

.child-info-meta {
  font-size: 0.78rem;
  color: var(--text-muted);
}

.child-active-tag {
  background: var(--primary);
  color: #fff;
  font-size: 0.72rem;
  font-weight: 700;
  padding: 2px 6px;
  border-radius: 4px;
}

/* 头像 Emoji 快捷选择 */
.avatar-picker {
  display: flex;
  gap: 8px;
  flex-wrap: wrap;
  margin-top: 6px;
}

.avatar-pick-item {
  width: 36px;
  height: 36px;
  border-radius: 50%;
  border: 1px solid var(--border-color);
  background: var(--bg-main);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 18px;
  cursor: pointer;
  transition: transform 0.15s;
}

.avatar-pick-item:hover, .avatar-pick-item.selected {
  border-color: var(--primary);
  transform: scale(1.15);
  background: var(--primary-light);
}

/* 表单输入框通用 */
.form-input {
  width: 100%;
  background: var(--bg-main);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-sm);
  padding: 10px 14px;
  font-size: 0.95rem;
  color: var(--text-main);
  outline: none;
  transition: border-color 0.2s;
}

.form-input:focus {
  border-color: var(--primary);
}

.modal-box {
  background: var(--card-bg);
  border-radius: var(--radius-lg);
  max-width: 680px;
  width: 100%;
  max-height: 85vh;
  display: flex;
  flex-direction: column;
  box-shadow: var(--shadow-lg);
  animation: scaleUp 0.25s ease-out;
  overflow: hidden;
}

.modal-header {
  padding: 18px 24px;
  border-bottom: 1px solid var(--border-color);
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.modal-title {
  font-size: 1.18rem;
  font-weight: 700;
  color: var(--text-main);
  display: flex;
  align-items: center;
  gap: 8px;
}

.modal-close-btn {
  background: none;
  border: none;
  font-size: 24px;
  color: var(--text-muted);
  cursor: pointer;
  padding: 4px;
}

.modal-close-btn:hover {
  color: var(--danger);
}

.modal-body {
  padding: 20px 24px;
  overflow-y: auto;
  flex: 1;
}

/* 答题卡网格 */
.card-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(44px, 1fr));
  gap: 8px;
}

.grid-cell {
  height: 44px;
  border-radius: var(--radius-sm);
  background: var(--bg-main);
  border: 1px solid var(--border-color);
  color: var(--text-main);
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: 700;
  font-size: 0.9rem;
  cursor: pointer;
  transition: all 0.15s;
  position: relative;
}

.grid-cell:hover {
  transform: scale(1.1);
  z-index: 2;
  border-color: var(--primary);
}

.grid-cell.current {
  border: 2px solid var(--accent);
  box-shadow: 0 0 0 2px rgba(2, 132, 199, 0.3);
}

.grid-cell.correct {
  background: var(--success);
  color: #fff;
  border-color: var(--success);
}

.grid-cell.wrong {
  background: var(--danger);
  color: #fff;
  border-color: var(--danger);
}

.grid-cell.starred::after {
  content: "★";
  position: absolute;
  top: 1px;
  right: 2px;
  font-size: 8px;
  color: #eab308;
}

/* 手册画册浏览 */
.handbook-modal-box {
  max-width: 950px;
  height: 90vh;
}

.handbook-viewer {
  display: flex;
  flex-direction: column;
  height: 100%;
}

.handbook-controls {
  padding: 10px 16px;
  background: var(--bg-main);
  border-bottom: 1px solid var(--border-color);
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
  flex-wrap: wrap;
}

.handbook-img-container {
  flex: 1;
  overflow: auto;
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 16px;
  background: #334155;
}

.handbook-img {
  max-height: 100%;
  max-width: 100%;
  object-fit: contain;
  box-shadow: 0 4px 20px rgba(0, 0, 0, 0.4);
  border-radius: 4px;
}

.handbook-chapters-bar {
  display: flex;
  gap: 6px;
  overflow-x: auto;
  padding: 8px 16px;
  background: var(--card-bg);
  border-top: 1px solid var(--border-color);
}

.chapter-btn {
  white-space: nowrap;
  background: var(--bg-main);
  border: 1px solid var(--border-color);
  padding: 4px 10px;
  border-radius: 12px;
  font-size: 0.78rem;
  color: var(--text-main);
  cursor: pointer;
  transition: all 0.2s;
}

.chapter-btn:hover, .chapter-btn.active {
  background: var(--primary);
  color: #fff;
  border-color: var(--primary);
}

/* 模拟考试成绩报告卡 */
.report-card {
  text-align: center;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 16px;
  padding: 20px 0;
}

.report-score-circle {
  width: 130px;
  height: 130px;
  border-radius: 50%;
  background: linear-gradient(135deg, var(--primary), var(--accent));
  color: #fff;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  box-shadow: 0 8px 25px rgba(5, 150, 105, 0.35);
}

.report-score-num {
  font-size: 2.5rem;
  font-weight: 800;
  line-height: 1;
}

.report-score-label {
  font-size: 0.82rem;
  opacity: 0.9;
}

.report-stats-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 16px;
  width: 100%;
  max-width: 450px;
  margin-top: 8px;
}

.report-stat-item {
  background: var(--bg-main);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  padding: 12px;
}

.report-stat-val {
  font-size: 1.3rem;
  font-weight: 700;
  color: var(--text-main);
}

.report-stat-lbl {
  font-size: 0.8rem;
  color: var(--text-muted);
}

/* 动效 */
@keyframes slideDown {
  from { opacity: 0; transform: translateY(-8px); }
  to { opacity: 1; transform: translateY(0); }
}

@keyframes scaleUp {
  from { opacity: 0; transform: scale(0.95); }
  to { opacity: 1; transform: scale(1); }
}

/* 移动端媒体查询适配 */
/* ========================================================
   移动端与平板端深度适配
   ======================================================== */
@media (max-width: 768px) {
  .app-container {
    padding: 12px;
    gap: 12px;
  }

  .question-card {
    padding: 18px 16px;
    border-radius: var(--radius-md);
  }

  .q-title {
    font-size: 1.08rem;
    line-height: 1.6;
  }

  .options-list {
    gap: 10px;
  }

  .option-item {
    padding: 12px 14px;
    font-size: 0.96rem;
    gap: 10px;
  }

  .opt-letter {
    width: 30px;
    height: 30px;
    min-width: 30px;
    font-size: 0.85rem;
  }

  .bottom-nav {
    gap: 8px;
    margin-top: 4px;
  }

  .bottom-nav .nav-btn {
    padding: 11px 12px;
    font-size: 0.88rem;
    white-space: nowrap;
  }

  .handbook-modal-box {
    height: 94vh;
  }
}

@media (max-width: 480px) {
  .app-container {
    padding: 8px 10px;
    gap: 10px;
  }

  .question-card {
    padding: 14px 12px;
    border-radius: var(--radius-sm);
  }

  .q-title {
    font-size: 1.02rem;
    line-height: 1.55;
  }

  .q-tags-bar {
    gap: 4px;
  }

  .q-type-badge,
  .q-source-badge,
  .q-hot-badge {
    font-size: 0.72rem;
    padding: 2px 6px;
  }

  .option-item {
    padding: 11px 12px;
    font-size: 0.92rem;
    gap: 8px;
    border-radius: var(--radius-sm);
  }

  .opt-letter {
    width: 28px;
    height: 28px;
    min-width: 28px;
    font-size: 0.82rem;
  }

  .bottom-nav {
    display: flex;
    align-items: center;
    gap: 6px;
  }

  #prev-btn, #next-btn {
    flex: 1.2;
    padding: 10px 6px;
    font-size: 0.84rem;
  }

  .bottom-nav > .bottom-tools {
    display: flex;
    gap: 6px;
    flex: 1.6;
  }

  .bottom-nav > .bottom-tools .nav-btn {
    flex: 1;
    padding: 10px 4px;
    font-size: 0.82rem;
  }

  .progress-panel {
    font-size: 0.8rem;
    gap: 8px;
  }

  #progress-text {
    min-width: 50px;
    font-size: 0.82rem;
  }

  .stats-badges {
    gap: 5px;
  }

  .badge-tag {
    padding: 2px 5px;
    font-size: 0.74rem;
  }

  .modal-overlay {
    padding: 6px;
  }

  .modal-box {
    width: 100%;
    max-height: 94vh;
    border-radius: var(--radius-md);
  }

  .modal-header {
    padding: 12px 14px;
  }

  .modal-title {
    font-size: 1.05rem;
  }

  .modal-body {
    padding: 14px;
  }

  .handbook-modal-box {
    height: 96vh;
    max-height: 96vh;
  }

  .handbook-controls {
    padding: 8px 10px;
    gap: 6px;
  }

  .handbook-img-container {
    padding: 8px;
  }
}

/* Keep controls and source tags aligned when labels wrap or screens narrow. */
.nav-brand { flex-shrink: 1; }
.nav-status-bar { min-width: 0; }
.mode-pills { flex-wrap: wrap; }
.q-meta-row { align-items: flex-start; flex-wrap: nowrap; }
.q-tags { flex: 1; min-width: 0; }
.q-source-badge { max-width: 100%; overflow-wrap: anywhere; }
.q-meta-row > button { flex-shrink: 0; }
.stats-badges { flex-wrap: wrap; justify-content: flex-end; }
.progress-panel { flex-wrap: wrap; }
.progress-track { min-width: 32px; }
.bottom-tools { display: flex; gap: 8px; min-width: 0; }
.modal-title { min-width: 0; overflow-wrap: anywhere; }
.modal-close-btn { flex-shrink: 0; }
.selection-order { flex-shrink: 0; font-size: .75rem; color: var(--primary); }
.answer-note { margin-top: 10px; white-space: pre-line; }
#child-chip-name, #sync-status-text {
  min-width: 0;
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
}
#child-chip-name { max-width: 160px; }
.child-chip-btn { max-width: 240px; }
.sync-badge-btn { max-width: 130px; }
.child-card-left { min-width: 0; flex: 1; }
.child-card-left > div:last-child { min-width: 0; }
.child-avatar-circle { flex-shrink: 0; }
.child-info-name { overflow-wrap: anywhere; }
.child-profile-card > button { flex-shrink: 0; }
.stats-summary-grid { display: grid; grid-template-columns: repeat(3, minmax(0, 1fr)); gap: 12px; text-align: center; }
.stats-metric { background: var(--bg-main); border: 1px solid var(--border-color); border-radius: var(--radius-md); padding: 14px; }
.stats-medals-grid { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 10px; }
.stats-actions { display: flex; flex-wrap: wrap; justify-content: space-between; gap: 8px; padding-top: 10px; border-top: 1px solid var(--border-color); }

@media (max-width: 640px) {
  .nav-status-bar .child-chip-btn { flex-shrink: 1; max-width: calc(100% - 200px); }
  .nav-status-bar .sync-badge-btn { max-width: 88px; }
  .mode-pills { display: grid; grid-template-columns: repeat(5, minmax(0, 1fr)); gap: 4px; }
  .pill-btn { min-width: 0; padding: 9px 4px; font-size: .8rem; justify-content: center; }
  .mode-label-full { display: none; }
  .mode-label-short { display: inline; }
  .bank-select-wrapper { flex-direction: row !important; align-items: center !important; gap: 8px !important; }
  .bank-select-label { font-size: .82rem; }
  .custom-select { min-height: 44px; font-size: 16px; padding: 8px; }
  .stats-badges:has(#exam-submit-btn:not([style*="display: none"])) { flex-basis: 100%; }
  .handbook-controls { flex-wrap: wrap; }
  .handbook-controls .nav-btn { padding: 8px; font-size: .8rem; }
}

/* 手机/平板切题按钮始终可见，为解析和设备底部安全区留出空间。 */
@media (max-width: 919px) {
  .app-container { padding-bottom: calc(112px + env(safe-area-inset-bottom, 0px)); }
  .question-card { touch-action: pan-y pinch-zoom; }
  .bottom-nav {
    position: fixed;
    inset: auto 0 0;
    z-index: 50;
    display: grid;
    grid-template-columns: minmax(0, 1fr) auto minmax(0, 1fr);
    align-items: center;
    gap: 6px 8px;
    margin: 0;
    padding: 8px max(10px, env(safe-area-inset-right, 0px)) calc(8px + env(safe-area-inset-bottom, 0px)) max(10px, env(safe-area-inset-left, 0px));
    background: var(--card-bg);
    border-top: 1px solid var(--border-color);
    box-shadow: 0 -4px 16px rgb(0 0 0 / .08);
  }
  .navigation-caption {
    grid-column: 1 / -1;
    display: flex;
    justify-content: space-between;
    gap: 8px;
    color: var(--text-muted);
    font-size: .7rem;
    line-height: 1.4;
  }
  #navigation-progress { flex-shrink: 0; font-variant-numeric: tabular-nums; }
  .bottom-nav .nav-btn { justify-content: center; min-width: 0; min-height: 48px; }
  .bottom-nav > .bottom-tools { display: flex; gap: 4px; }
  .bottom-nav > .bottom-tools .nav-btn { flex-direction: column; gap: 0; padding: 4px; width: 44px; font-size: .65rem; }
  .bottom-tools .nav-btn > span:first-child { font-size: 1rem; }
  #prev-btn, #next-btn { width: 100%; padding: 12px 6px; font-size: .88rem; }
}

@media (max-width: 480px) {
  .stats-summary-grid { gap: 8px; }
  .stats-metric { padding: 10px 6px; }
  .stats-medals-grid { grid-template-columns: minmax(0, 1fr); }
  .stats-actions { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); }
  .stats-actions .nav-btn { min-width: 0; padding: 10px 6px; font-size: .85rem; justify-content: center; }
}