:root {
  --bg-primary: #f8fafc;
  --bg-card: #ffffff;
  --text-primary: #0f172a;
  --text-secondary: #475569;
  --text-light: #94a3b8;
  --primary: #2563eb;
  --primary-hover: #1d4ed8;
  --primary-light: #eff6ff;
  --border: #e2e8f0;
  --border-hover: #cbd5e1;
  --success: #15803d;
  --success-bg: #f0fdf4;
  --success-border: #bbf7d0;
  --danger: #b91c1c;
  --danger-bg: #fef2f2;
  --danger-border: #fecaca;
  --warning: #b45309;
  --warning-bg: #fffbeb;
  --warning-border: #fde68a;
  
  --font-sans: 'Inter', -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", "Microsoft YaHei", sans-serif;
  --font-mono: 'JetBrains Mono', 'Consolas', 'Courier New', monospace;
  --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.05);
  --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.1), 0 2px 4px -1px rgba(0, 0, 0, 0.06);
  --radius-sm: 4px;
  --radius-md: 8px;
  --transition: all 0.2s cubic-bezier(0.4, 0, 0.2, 1);
}

* {
  box-sizing: border-box;
}

body {
  background-color: var(--bg-primary);
  color: var(--text-primary);
  font-family: var(--font-sans);
  margin: 0;
  padding: 0;
  line-height: 1.6;
}

/* ================= 头部导航栏 ================= */
.app-header {
  background-color: var(--bg-card);
  border-bottom: 1px solid var(--border);
  position: sticky;
  top: 0;
  z-index: 50;
  height: 64px;
  box-shadow: var(--shadow-sm);
}

.header-container {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 24px;
  display: flex;
  justify-content: space-between;
  align-items: center;
  height: 100%;
}

.brand {
  display: flex;
  align-items: center;
  gap: 12px;
}

.brand-badge {
  background-color: var(--text-primary);
  color: var(--bg-card);
  font-weight: 700;
  font-size: 0.75rem;
  padding: 2px 6px;
  border-radius: var(--radius-sm);
  letter-spacing: 1px;
}

.brand h1 {
  font-size: 1.1rem;
  font-weight: 700;
  margin: 0;
  color: var(--text-primary);
}

.nav-links {
  display: flex;
  align-items: center;
  gap: 4px;
  margin-left: 24px;
  flex: 1;
}

.user-menu {
  display: flex;
  align-items: center;
  gap: 12px;
  flex-shrink: 0;
}

.user-name-tag {
  font-size: 0.85rem;
  font-weight: 600;
  color: var(--text-secondary);
  border-right: 1px solid var(--border);
  padding-right: 12px;
}

/* ================= 通用卡片与按钮 ================= */
.card {
  background-color: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius-md);
  box-shadow: var(--shadow-sm);
  padding: 24px;
  margin-bottom: 24px;
}

.btn {
  font-family: var(--font-sans);
  font-size: 0.9rem;
  font-weight: 500;
  padding: 10px 18px; /* 确保触摸热区高度 */
  min-height: 44px;
  border-radius: var(--radius-sm);
  border: 1px solid var(--border);
  background-color: var(--bg-card);
  color: var(--text-secondary);
  cursor: pointer;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  transition: var(--transition);
}

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

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

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

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

.success-btn:hover {
  background-color: #166534;
  color: #ffffff;
  border-color: #166534;
}

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

.danger-btn:hover {
  background-color: #991b1b;
  color: #ffffff;
  border-color: #991b1b;
}

.danger-outline-btn {
  color: var(--danger);
  border-color: var(--danger-border);
}

.danger-outline-btn:hover {
  background-color: var(--danger-bg);
  color: var(--danger);
  border-color: var(--danger);
}

.compact-btn {
  padding: 6px 12px;
  font-size: 0.8rem;
  min-height: 32px;
}

.btn-block {
  display: flex;
  width: 100%;
}

.nav-btn {
  border: none;
  background: none;
  font-size: 0.9rem;
  font-weight: 500;
  color: var(--text-secondary);
  padding: 8px 12px;
  border-radius: var(--radius-sm);
  cursor: pointer;
  transition: var(--transition);
  display: flex;
  align-items: center;
  gap: 6px;
  min-height: 40px;
}

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

.nav-btn.active {
  background-color: var(--primary-light);
  color: var(--primary);
  font-weight: 600;
}

.wrong-badge {
  background-color: var(--danger);
  color: #ffffff;
  font-size: 0.75rem;
  font-weight: 600;
  padding: 2px 6px;
  border-radius: 10px;
}

/* ================= 主体结构与单页路由 ================= */
#app {
  max-width: 1200px;
  margin: 24px auto;
  padding: 0 24px 64px 24px;
}

.app-view {
  animation: fadeIn 0.25s ease-out;
}

.hidden {
  display: none !important;
}

@keyframes fadeIn {
  from { opacity: 0; transform: translateY(4px); }
  to { opacity: 1; transform: translateY(0); }
}

/* ================= 视图 0：登录与注册 ================= */
.auth-container {
  max-width: 440px;
  margin: 80px auto;
}

.auth-tabs {
  display: grid;
  grid-template-columns: 1fr 1fr;
  border-bottom: 2px solid var(--border);
  margin-bottom: 24px;
}

.auth-tab-btn {
  border: none;
  background: none;
  font-size: 1rem;
  font-weight: 500;
  color: var(--text-secondary);
  padding: 12px 0;
  cursor: pointer;
  text-align: center;
  transition: var(--transition);
  border-bottom: 2px solid transparent;
  margin-bottom: -2px;
}

.auth-tab-btn:hover {
  color: var(--text-primary);
}

.auth-tab-btn.active {
  color: var(--primary);
  font-weight: 600;
  border-bottom-color: var(--primary);
}

.auth-form {
  display: flex;
  flex-direction: column;
  gap: 16px;
}

.auth-notice {
  font-size: 0.75rem;
  color: var(--warning);
  background-color: var(--warning-bg);
  border: 1px dashed var(--warning-border);
  padding: 10px 14px;
  border-radius: var(--radius-sm);
  line-height: 1.4;
}

/* 输入框全局样式 */
.form-group input {
  font-family: var(--font-sans);
  font-size: 0.95rem;
  padding: 10px 14px;
  border-radius: var(--radius-sm);
  border: 1px solid var(--border);
  color: var(--text-primary);
  background-color: var(--bg-card);
  outline: none;
  transition: var(--transition);
  min-height: 44px;
}

.form-group input:focus {
  border-color: var(--primary);
  box-shadow: 0 0 0 2px var(--primary-light);
}

/* ================= 视图 1：控制面板样式 ================= */
/* 统计卡片网格 */
.stats-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 20px;
  margin-bottom: 24px;
}

.stats-card {
  background-color: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius-md);
  padding: 20px;
  box-shadow: var(--shadow-sm);
}

.stats-card.warning {
  border-left: 4px solid var(--warning);
}

.stats-label {
  font-size: 0.85rem;
  color: var(--text-secondary);
  font-weight: 500;
  margin-bottom: 8px;
}

.stats-value {
  font-size: 2rem;
  font-weight: 700;
  color: var(--text-primary);
  line-height: 1.2;
  margin-bottom: 8px;
}

.stats-desc {
  font-size: 0.75rem;
  color: var(--text-light);
}

.stats-progress-track {
  height: 6px;
  background-color: var(--border);
  border-radius: 3px;
  overflow: hidden;
  margin-top: 12px;
}

.stats-progress-fill {
  height: 100%;
  background-color: var(--primary);
  border-radius: 3px;
  transition: width 0.4s ease;
}

/* 学习中心汇总数据 */
.learning-summary-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 16px;
  margin-bottom: 20px;
}

.learning-metric {
  background-color: var(--bg-primary);
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  padding: 14px;
  display: flex;
  flex-direction: column;
  gap: 4px;
}

.learning-metric span {
  font-size: 0.8rem;
  color: var(--text-secondary);
}

.learning-metric strong {
  font-size: 1.2rem;
  color: var(--text-primary);
}

.learning-plan-row {
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 24px;
  background-color: var(--primary-light);
  border: 1px solid var(--primary);
  padding: 16px;
  border-radius: var(--radius-sm);
  margin-bottom: 16px;
}

.plan-details {
  flex: 1;
}

.learning-eyebrow {
  font-size: 0.75rem;
  font-weight: 700;
  text-transform: uppercase;
  color: var(--primary);
  margin-bottom: 4px;
}

.learning-plan-text {
  font-size: 0.9rem;
  color: var(--text-primary);
}

.goal-form {
  display: flex;
  align-items: flex-end;
  gap: 12px;
  flex-shrink: 0;
}

.goal-form-fields {
  display: flex;
  gap: 12px;
}

.form-group.compact {
  display: flex;
  flex-direction: column;
  gap: 4px;
}

.form-group.compact label {
  font-size: 0.75rem;
  color: var(--text-secondary);
}

.form-group.compact input {
  min-height: 36px;
  height: 36px;
  padding: 4px 10px;
  font-size: 0.85rem;
}

.learning-comparison {
  display: flex;
  gap: 24px;
  font-size: 0.8rem;
  color: var(--text-secondary);
  margin-bottom: 24px;
  border-bottom: 1px solid var(--border);
  padding-bottom: 12px;
}

/* 做题记录表格 */
.session-history-heading {
  font-size: 0.95rem;
  font-weight: 600;
  margin-bottom: 12px;
}

.session-history-empty {
  font-size: 0.85rem;
  color: var(--text-light);
  padding: 16px;
  border: 1px dashed var(--border);
  border-radius: var(--radius-sm);
  text-align: center;
}

.session-history-table-wrap, .table-wrap, .leaderboard-table-wrap, .admin-table-wrap, .detail-history-container {
  width: 100%;
  overflow-x: auto;
}

.data-table {
  width: 100%;
  border-collapse: collapse;
  text-align: left;
  font-size: 0.85rem;
}

.data-table th, .data-table td {
  padding: 10px 14px;
  border-bottom: 1px solid var(--border);
}

.data-table th {
  background-color: var(--bg-primary);
  font-weight: 600;
  color: var(--text-secondary);
}

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

/* 仪表盘主布局 */
.dashboard-layout {
  display: grid;
  grid-template-columns: 400px 1fr;
  gap: 24px;
  align-items: start;
}

.section-title {
  font-size: 1.1rem;
  font-weight: 600;
  margin-top: 0;
  margin-bottom: 20px;
  padding-bottom: 10px;
  border-bottom: 1px solid var(--border);
  color: var(--text-primary);
}

/* 配置表单 */
.config-form {
  display: flex;
  flex-direction: column;
  gap: 16px;
}

.form-group {
  display: flex;
  flex-direction: column;
  gap: 6px;
}

.form-group label {
  font-size: 0.85rem;
  font-weight: 500;
  color: var(--text-secondary);
}

.form-row {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 12px;
}

.config-form select {
  font-family: var(--font-sans);
  font-size: 0.9rem;
  padding: 8px 12px;
  border-radius: var(--radius-sm);
  border: 1px solid var(--border);
  color: var(--text-primary);
  background-color: var(--bg-card);
  outline: none;
  cursor: pointer;
  transition: var(--transition);
  min-height: 44px;
}

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

/* 按分类明细进度 */
.topic-grid {
  display: flex;
  flex-direction: column;
  gap: 14px;
}

.topic-item {
  padding: 12px 16px;
  background-color: var(--bg-primary);
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
}

.topic-item-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 8px;
  font-size: 0.9rem;
}

.topic-name {
  font-weight: 600;
  color: var(--text-primary);
}

.topic-count-stats {
  font-size: 0.8rem;
  color: var(--text-secondary);
}

.topic-progress-row {
  display: flex;
  align-items: center;
  gap: 12px;
}

.topic-bar-container {
  flex: 1;
  height: 6px;
  background-color: var(--border);
  border-radius: 3px;
  overflow: hidden;
}

.topic-bar-fill {
  height: 100%;
  background-color: var(--primary);
  border-radius: 3px;
}

.topic-accuracy-pct {
  font-size: 0.8rem;
  font-weight: 600;
  color: var(--text-secondary);
  width: 45px;
  text-align: right;
}

.danger-zone {
  margin-top: 32px;
  padding-top: 20px;
  border-top: 1px solid var(--border);
}

/* ================= 视图 2：答题练习区样式 ================= */
.practice-layout {
  display: grid;
  grid-template-columns: 280px 1fr;
  gap: 24px;
  align-items: start;
}

.sidebar-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 12px;
}

#practice-progress-text {
  font-size: 0.85rem;
  font-weight: 600;
  color: var(--text-primary);
}

.progress-bar-container {
  height: 6px;
  background-color: var(--border);
  border-radius: 3px;
  overflow: hidden;
  margin-bottom: 14px;
}

.progress-bar-fill {
  height: 100%;
  background-color: var(--primary);
  border-radius: 3px;
  transition: width 0.2s ease;
}

.session-score-preview {
  font-size: 0.85rem;
  font-weight: 700;
  color: var(--primary);
  margin-bottom: 16px;
}

.sheet-title {
  font-size: 0.85rem;
  font-weight: 600;
  color: var(--text-secondary);
  text-transform: uppercase;
  letter-spacing: 0.5px;
  margin-bottom: 12px;
}

.sheet-grid {
  display: grid;
  grid-template-columns: repeat(5, 1fr);
  gap: 8px;
  margin-bottom: 20px;
}

.sheet-btn {
  aspect-ratio: 1;
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  background-color: var(--bg-card);
  color: var(--text-secondary);
  font-size: 0.9rem;
  font-weight: 600;
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  transition: var(--transition);
  min-height: 38px;
}

.sheet-btn:hover {
  border-color: var(--primary);
  background-color: var(--primary-light);
  color: var(--primary);
}

.sheet-btn.current {
  border-color: var(--primary);
  background-color: var(--primary);
  color: #ffffff;
  box-shadow: 0 0 0 2px var(--primary-light);
}

.sheet-btn.correct {
  background-color: var(--success-bg);
  border-color: var(--success-border);
  color: var(--success);
}

.sheet-btn.correct.current {
  background-color: var(--success);
  border-color: var(--success);
  color: #ffffff;
  box-shadow: 0 0 0 2px var(--success-bg);
}

.sheet-btn.incorrect {
  background-color: var(--danger-bg);
  border-color: var(--danger-border);
  color: var(--danger);
}

.sheet-btn.incorrect.current {
  background-color: var(--danger);
  border-color: var(--danger);
  color: #ffffff;
  box-shadow: 0 0 0 2px var(--danger-bg);
}

.sheet-legend {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  border-top: 1px solid var(--border);
  padding-top: 14px;
}

.legend-item {
  font-size: 0.75rem;
  color: var(--text-secondary);
  display: flex;
  align-items: center;
  gap: 6px;
}

.legend-dot {
  width: 10px;
  height: 10px;
  border-radius: 2px;
  border: 1px solid var(--border);
}

.legend-dot.unanswered { background-color: var(--bg-card); }
.legend-dot.correct { background-color: var(--success-bg); border-color: var(--success-border); }
.legend-dot.incorrect { background-color: var(--danger-bg); border-color: var(--danger-border); }

/* 右侧题目卡片样式 */
.question-card {
  min-height: 400px;
  display: flex;
  flex-direction: column;
}

.question-meta {
  display: flex;
  align-items: center;
  flex-wrap: wrap;
  gap: 8px;
  margin-bottom: 18px;
}

.meta-badge {
  font-size: 0.75rem;
  font-weight: 600;
  padding: 2px 8px;
  border-radius: var(--radius-sm);
  text-transform: uppercase;
}

.meta-badge.number { background-color: var(--primary-light); color: var(--primary); }
.meta-badge.type { background-color: var(--text-primary); color: #ffffff; }
.meta-badge.level { background-color: #f1f5f9; color: var(--text-secondary); border: 1px solid var(--border); }
.meta-topic { font-size: 0.8rem; color: var(--text-light); margin-left: auto; }

.question-stem {
  font-size: 1.05rem;
  font-weight: 500;
  color: var(--text-primary);
  margin-bottom: 24px;
  white-space: pre-line;
}

/* 题目包含的代码块支持 */
.question-stem pre, .explanation-content pre {
  background-color: #0f172a;
  color: #e2e8f0;
  padding: 14px 18px;
  border-radius: var(--radius-sm);
  font-family: var(--font-mono);
  font-size: 0.85rem;
  overflow-x: auto;
  margin: 12px 0;
  border: 1px solid #1e293b;
  line-height: 1.4;
}

.question-stem code, .explanation-content code {
  font-family: var(--font-mono);
  background-color: #f1f5f9;
  color: #0f172a;
  padding: 2px 6px;
  border-radius: 3px;
  font-size: 0.85rem;
}

.question-stem pre code, .explanation-content pre code {
  background-color: transparent;
  color: inherit;
  padding: 0;
  font-size: inherit;
}

/* 选项列表 */
.options-list {
  display: flex;
  flex-direction: column;
  gap: 12px;
  margin-bottom: 28px;
}

.option-item {
  border: 1px solid var(--border);
  border-radius: var(--radius-md);
  padding: 14px 18px;
  cursor: pointer;
  display: flex;
  align-items: flex-start;
  gap: 14px;
  transition: var(--transition);
  user-select: none;
  min-height: 44px; /* 触摸目标要求 */
}

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

.option-key {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 24px;
  height: 24px;
  border-radius: 50%;
  border: 1px solid var(--text-secondary);
  font-weight: 600;
  font-size: 0.8rem;
  flex-shrink: 0;
  margin-top: 1px;
}

/* 多选题为方角，单选题为圆角 */
.option-item.multiselect .option-key {
  border-radius: var(--radius-sm);
}

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

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

.option-item.selected .option-key {
  background-color: var(--primary);
  border-color: var(--primary);
  color: #ffffff;
}

.option-item.selected .option-text {
  color: var(--primary);
  font-weight: 500;
}

/* 选项置灰 */
.option-item.disabled {
  pointer-events: none;
  opacity: 0.85;
}

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

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

.option-item.correct-answer .option-text {
  color: var(--success) !important;
  font-weight: 600;
}

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

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

.option-item.wrong-selected .option-text {
  color: var(--danger) !important;
  font-weight: 600;
}

/* 题目来源面板样式 */
.provenance-panel {
  margin-top: 16px;
  border-top: 1px dashed var(--border);
  padding-top: 16px;
}

.provenance-heading {
  font-size: 0.75rem;
  font-weight: 700;
  text-transform: uppercase;
  color: var(--text-light);
  margin-bottom: 6px;
}

.provenance-label {
  display: inline-block;
  font-size: 0.7rem;
  font-weight: 600;
  padding: 1px 6px;
  border-radius: var(--radius-sm);
  background-color: #f1f5f9;
  color: var(--text-secondary);
  margin-bottom: 6px;
}

.provenance-label.provenance-ai_document_grounded {
  background-color: var(--warning-bg);
  color: var(--warning);
}

.provenance-title {
  font-size: 0.85rem;
  font-weight: 600;
  color: var(--text-primary);
  margin-bottom: 4px;
}

.provenance-details {
  font-size: 0.75rem;
  color: var(--text-secondary);
  margin-bottom: 6px;
}

.provenance-panel a {
  font-size: 0.75rem;
  color: var(--primary);
  text-decoration: none;
  font-weight: 500;
}

.provenance-panel a:hover {
  text-decoration: underline;
}

/* 反包面板（提交答案后滑出） */
.feedback-panel {
  margin-bottom: 28px;
  border-radius: var(--radius-md);
  border: 1px solid var(--border);
  overflow: hidden;
  animation: slideDown 0.25s ease-out;
}

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

.feedback-header {
  padding: 12px 18px;
  display: flex;
  align-items: center;
  gap: 16px;
  border-bottom: 1px solid var(--border);
}

.feedback-badge {
  font-size: 0.85rem;
  font-weight: 700;
  padding: 3px 8px;
  border-radius: var(--radius-sm);
  color: #ffffff;
}

#feedback-correct-answer {
  font-weight: 600;
  font-size: 0.95rem;
}

/* 反馈状态颜色 */
.feedback-panel.correct-feedback {
  background-color: var(--success-bg);
  border-color: var(--success-border);
}

.feedback-panel.correct-feedback .feedback-header {
  border-color: var(--success-border);
}

.feedback-panel.correct-feedback .feedback-badge {
  background-color: var(--success);
}

.feedback-panel.correct-feedback #feedback-correct-answer {
  color: var(--success);
}

.feedback-panel.incorrect-feedback {
  background-color: var(--danger-bg);
  border-color: var(--danger-border);
}

.feedback-panel.incorrect-feedback .feedback-header {
  border-color: var(--danger-border);
}

.feedback-panel.incorrect-feedback .feedback-badge {
  background-color: var(--danger);
}

.feedback-panel.incorrect-feedback #feedback-correct-answer {
  color: var(--danger);
}

.feedback-body {
  padding: 16px 18px;
}

.explanation-title {
  font-size: 0.85rem;
  font-weight: 600;
  color: var(--text-primary);
  margin-bottom: 8px;
}

.explanation-content {
  font-size: 0.9rem;
  color: var(--text-secondary);
  white-space: pre-line;
  font-family: var(--font-sans);
}

.question-actions {
  display: flex;
  gap: 12px;
  margin-top: auto;
  border-top: 1px solid var(--border);
  padding-top: 20px;
}

.question-actions .btn {
  min-width: 100px;
}

#btn-submit-answer, #btn-next-question, #btn-finish-practice {
  margin-left: auto;
}

/* ================= 视图 3：错题本样式 ================= */
.wrongbook-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 24px;
}

.wrongbook-info h2 {
  margin: 0 0 6px 0;
  font-size: 1.3rem;
  color: var(--text-primary);
}

.wrongbook-info p {
  margin: 0;
  font-size: 0.85rem;
  color: var(--text-secondary);
}

.empty-state {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  padding: 64px 32px;
  text-align: center;
}

.empty-icon {
  width: 56px;
  height: 56px;
  border-radius: 50%;
  background-color: var(--success-bg);
  color: var(--success);
  font-size: 1.8rem;
  display: flex;
  align-items: center;
  justify-content: center;
  margin-bottom: 18px;
}

.empty-state h3 {
  font-size: 1.15rem;
  margin: 0 0 8px 0;
  color: var(--text-primary);
}

.empty-state p {
  font-size: 0.9rem;
  color: var(--text-secondary);
  margin: 0 0 24px 0;
  max-width: 380px;
}

/* 错题列表卡片 */
.wrong-question-card {
  background-color: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius-md);
  padding: 24px;
  margin-bottom: 18px;
  box-shadow: var(--shadow-sm);
  position: relative;
}

.wrong-card-meta {
  display: flex;
  align-items: center;
  gap: 8px;
  margin-bottom: 14px;
}

.wrong-card-stem {
  font-size: 0.95rem;
  font-weight: 600;
  color: var(--text-primary);
  margin-bottom: 18px;
}

.wrong-card-options {
  display: flex;
  flex-direction: column;
  gap: 8px;
  margin-bottom: 18px;
  border-left: 2px solid var(--border);
  padding-left: 14px;
}

.wrong-card-option-item {
  font-size: 0.85rem;
  color: var(--text-secondary);
  padding: 2px 0;
}

.wrong-card-actions {
  display: flex;
  justify-content: flex-end;
  gap: 12px;
  border-top: 1px solid var(--border);
  padding-top: 14px;
  margin-top: 18px;
}

.wrong-card-challenge-zone {
  margin-top: 18px;
  background-color: var(--bg-primary);
  border: 1px dashed var(--border);
  border-radius: var(--radius-sm);
  padding: 16px;
  animation: slideDown 0.2s ease-out;
}

.wrong-card-challenge-title {
  font-size: 0.8rem;
  font-weight: 700;
  color: var(--text-secondary);
  margin-bottom: 12px;
}

/* ================= 视图 4：排行榜 ================= */
.leaderboard-header {
  margin-bottom: 24px;
}

.leaderboard-header h2 {
  margin: 0 0 6px 0;
  font-size: 1.3rem;
}

.leaderboard-header p {
  margin: 0;
  font-size: 0.85rem;
  color: var(--text-secondary);
}

.leaderboard-table-wrap {
  padding: 12px;
}

/* ================= 视图 5：管理后台 ================= */
.admin-header {
  margin-bottom: 24px;
}

.admin-header h2 {
  margin: 0 0 6px 0;
}

.admin-header p {
  margin: 0 0 16px 0;
  font-size: 0.85rem;
  color: var(--text-secondary);
}

.admin-tabs {
  display: flex;
  gap: 12px;
  border-bottom: 1px solid var(--border);
  padding-bottom: 8px;
}

.admin-tabs .auth-tab-btn {
  font-size: 0.9rem;
  padding: 8px 16px;
}

.admin-panel {
  animation: fadeIn 0.2s ease-out;
}

/* 用户详细记录 Modal */
.user-detail-card {
  width: 640px !important;
  max-width: 95% !important;
}

.detail-grid {
  display: grid;
  grid-template-columns: repeat(5, 1fr);
  gap: 12px;
  background-color: var(--bg-primary);
  padding: 14px;
  border-radius: var(--radius-sm);
  border: 1px solid var(--border);
  margin-bottom: 20px;
}

.detail-item {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 4px;
}

.detail-item span {
  font-size: 0.75rem;
  color: var(--text-secondary);
  text-align: center;
}

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

.detail-history-wrap h4 {
  margin: 0 0 10px 0;
  font-size: 0.9rem;
  font-weight: 600;
}

.detail-history-container {
  max-height: 240px;
  overflow-y: auto;
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  background-color: var(--bg-card);
  margin-bottom: 20px;
}

/* 403 页面 */
.forbidden-view {
  max-width: 460px;
  margin: 100px auto;
  text-align: center;
  padding: 48px 24px;
}

.forbidden-icon {
  font-size: 3rem;
  margin-bottom: 16px;
}

.forbidden-view h3 {
  font-size: 1.25rem;
  margin: 0 0 8px 0;
}

.forbidden-view p {
  font-size: 0.9rem;
  color: var(--text-secondary);
  margin: 0 0 24px 0;
}

/* ================= 全局反馈组件 ================= */
/* 全局加载遮罩 */
.loading-overlay {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  background-color: rgba(248, 250, 252, 0.85);
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 16px;
  z-index: 1000;
  backdrop-filter: blur(2px);
}

.loading-spinner {
  width: 40px;
  height: 40px;
  border: 3px solid var(--border);
  border-top-color: var(--primary);
  border-radius: 50%;
  animation: spin 0.8s linear infinite;
}

.loading-text {
  font-size: 0.9rem;
  color: var(--text-secondary);
  font-weight: 500;
}

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

/* 全局 Toast */
.toast-container {
  position: fixed;
  top: 24px;
  left: 50%;
  transform: translateX(-50%);
  display: flex;
  flex-direction: column;
  gap: 10px;
  z-index: 1100;
  width: 320px;
  max-width: 90%;
}

.toast {
  background-color: #1e293b;
  color: #ffffff;
  padding: 12px 16px;
  border-radius: var(--radius-sm);
  font-size: 0.85rem;
  font-weight: 500;
  box-shadow: var(--shadow-md);
  display: flex;
  align-items: center;
  justify-content: space-between;
  animation: toastIn 0.25s cubic-bezier(0.16, 1, 0.3, 1) forwards;
}

.toast.error {
  border-left: 4px solid var(--danger);
}

.toast.success {
  border-left: 4px solid var(--success);
}

@keyframes toastIn {
  from { opacity: 0; transform: translateY(-16px); }
  to { opacity: 1; transform: translateY(0); }
}

/* 二次确认模态框 */
.modal-backdrop {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  background-color: rgba(15, 23, 42, 0.4);
  backdrop-filter: blur(2px);
  display: flex;
  align-items: center;
  justify-content: center;
  z-index: 1000;
}

.modal-card {
  background-color: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius-md);
  width: 420px;
  max-width: 90%;
  padding: 24px;
  box-shadow: var(--shadow-md);
  animation: slideDown 0.25s cubic-bezier(0.16, 1, 0.3, 1);
}

.modal-card h3 {
  margin: 0 0 10px 0;
  font-size: 1.1rem;
  color: var(--text-primary);
}

.modal-card p {
  margin: 0 0 24px 0;
  font-size: 0.9rem;
  color: var(--text-secondary);
}

.modal-actions {
  display: flex;
  justify-content: flex-end;
  gap: 12px;
}

/* 方向选择器 */
.track-selector-card {
  background-color: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius-md);
  box-shadow: var(--shadow-sm);
}

.track-selector-flex {
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 16px;
  flex-wrap: wrap;
}

.track-selector-title {
  font-size: 0.95rem;
  font-weight: 600;
  color: var(--text-primary);
}

.track-btn-group {
  display: flex;
  gap: 8px;
  flex-wrap: wrap;
}

.track-btn-group .btn {
  min-height: 36px;
  height: 36px;
  padding: 6px 12px;
  font-size: 0.85rem;
  transition: var(--transition);
}

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

/* ================= 骨架屏占位图 ================= */
.loading-placeholder {
  padding: 24px;
  text-align: center;
  color: var(--text-light);
  font-size: 0.9rem;
}

/* ================= 响应式媒体查询 ================= */

/* 1440px 桌面端及大屏幕优化 */
@media (min-width: 992px) {
  #app {
    margin-top: 40px;
  }
}

/* 768px - 991px 中等屏幕：左右布局自适应 */
@media (max-width: 991px) {
  .dashboard-layout {
    grid-template-columns: 1fr;
  }
  
  .practice-layout {
    grid-template-columns: 240px 1fr;
  }
}

/* 375px - 767px 移动端及窄屏优化 */
@media (max-width: 767px) {
  .header-container {
    padding: 0 16px;
    flex-wrap: wrap;
    height: auto;
    min-height: 64px;
    padding-bottom: 8px;
    gap: 8px;
  }
  
  .brand {
    width: 100%;
    justify-content: space-between;
    border-bottom: 1px solid var(--border);
    padding: 8px 0;
  }
  
  .brand h1 {
    font-size: 1rem;
  }
  
  .nav-links {
    margin-left: 0;
    width: 100%;
    justify-content: space-between;
    order: 3;
    overflow-x: auto;
    padding-bottom: 4px;
  }
  
  .nav-btn {
    min-height: 36px;
    padding: 6px 8px;
    font-size: 0.8rem;
  }
  
  .user-menu {
    position: absolute;
    right: 16px;
    top: 12px;
  }
  
  .user-name-tag {
    border: none;
    padding-right: 0;
  }

  #app {
    margin-top: 16px;
    padding: 0 16px 48px 16px;
  }
  
  .card {
    padding: 16px;
  }
  
  /* 统计面板网格变为两栏 */
  .stats-grid {
    grid-template-columns: repeat(2, 1fr);
    gap: 12px;
  }
  
  .stats-card {
    padding: 14px;
  }
  
  .stats-value {
    font-size: 1.6rem;
  }
  
  /* 学习中心小细节 */
  .learning-summary-grid {
    grid-template-columns: repeat(2, 1fr);
    gap: 10px;
  }
  
  .learning-plan-row {
    flex-direction: column;
    align-items: stretch;
    gap: 12px;
  }
  
  .goal-form {
    align-items: stretch;
  }
  
  .goal-form-fields {
    flex-direction: column;
    gap: 8px;
  }

  /* 快速开始配置布局 */
  .form-row {
    grid-template-columns: 1fr;
    gap: 16px;
  }
  
  /* 做题界面左右布局折叠为单栏，且答题进度移至上方 */
  .practice-layout {
    grid-template-columns: 1fr;
    gap: 16px;
  }
  
  .practice-sidebar {
    order: -1; /* 保证进度栏在题目上方 */
  }
  
  .sheet-grid {
    grid-template-columns: repeat(10, 1fr); /* 移动端答题卡横向紧凑排列 */
  }
  
  .sheet-btn {
    font-size: 0.8rem;
    min-height: 32px;
  }
  
  .question-meta {
    gap: 4px;
  }
  
  .meta-topic {
    width: 100%;
    margin-left: 0;
    margin-top: 6px;
  }
  
  .option-item {
    padding: 12px 14px;
  }
  
  .question-actions {
    flex-wrap: wrap;
  }
  
  .question-actions .btn {
    flex: 1 1 40%;
  }
  
  #btn-submit-answer, #btn-next-question, #btn-finish-practice {
    order: 3;
    flex: 1 1 100%;
    margin-left: 0;
  }
  
  .wrongbook-header {
    flex-direction: column;
    align-items: flex-start;
    gap: 14px;
  }
  
  .wrongbook-controls {
    width: 100%;
  }
  
  .wrongbook-controls .btn {
    width: 100%;
  }
  
  /* 排行榜和后台管理表格 */
  .leaderboard-header, .admin-header {
    padding: 14px;
  }
  
  .data-table th, .data-table td {
    padding: 8px 10px;
    font-size: 0.8rem;
  }

  /* 针对 480px 以下极窄屏幕进行适配优化，防止内容溢出 */
  @media (max-width: 480px) {
    .stats-grid {
      grid-template-columns: 1fr;
    }
    .learning-summary-grid {
      grid-template-columns: 1fr;
    }
    .track-selector-flex {
      flex-direction: column;
      align-items: flex-start;
      gap: 12px;
    }
    .track-btn-group {
      width: 100%;
    }
    .track-btn-group .btn {
      flex: 1 1 auto;
      text-align: center;
    }
    .detail-grid {
      grid-template-columns: repeat(2, 1fr);
    }
    .modal-card {
      padding: 16px;
    }
    .modal-actions {
      flex-direction: column;
      align-items: stretch;
      gap: 10px;
    }
    .modal-actions .btn {
      width: 100%;
      margin: 0 !important;
    }
    .question-actions .btn {
      width: 100%;
    }
  }
}
/* password-10-username-5-limit-released */