/* ==========================================================================
   人工智能训练师（三级）理论模拟考试系统 - 高端现代设计系统 (Design System)
   ========================================================================== */

:root {
  /* 核心主色调：深邃科技靛蓝 (Electric Indigo) */
  --primary: #4f46e5;
  --primary-hover: #4338ca;
  --primary-light: #eef2ff;
  --primary-border: #c7d2fe;
  --primary-gradient: linear-gradient(135deg, #4f46e5 0%, #6366f1 100%);
  --primary-glow: 0 8px 20px -4px rgba(79, 70, 229, 0.35);

  /* 语义状态色：翡翠玉绿 (Emerald) · 玫瑰绯红 (Crimson Rose) · 琥珀暖金 (Amber) */
  --success: #059669;
  --success-hover: #047857;
  --success-light: #ecfdf5;
  --success-border: #a7f3d0;
  --success-gradient: linear-gradient(135deg, #059669 0%, #10b981 100%);

  --danger: #e11d48;
  --danger-hover: #be123c;
  --danger-light: #fff1f2;
  --danger-border: #fecdd3;
  --danger-gradient: linear-gradient(135deg, #e11d48 0%, #f43f5e 100%);

  --warning: #d97706;
  --warning-hover: #b45309;
  --warning-light: #fffbeb;
  --warning-border: #fde68a;
  --warning-gradient: linear-gradient(135deg, #d97706 0%, #f59e0b 100%);

  --violet: #7c3aed;
  --violet-light: #faf5ff;
  --violet-border: #e9d5ff;

  --cyan: #0284c7;
  --cyan-light: #f0f9ff;
  --cyan-border: #bae6fd;

  /* 高级 Slate 灰阶 */
  --slate-50: #f8fafc;
  --slate-100: #f1f5f9;
  --slate-200: #e2e8f0;
  --slate-300: #cbd5e1;
  --slate-400: #94a3b8;
  --slate-500: #64748b;
  --slate-600: #475569;
  --slate-700: #334155;
  --slate-800: #1e293b;
  --slate-900: #0f172a;

  /* 多层次环境投影 (Ambient Shadows) */
  --shadow-xs: 0 1px 2px 0 rgba(15, 23, 42, 0.04);
  --shadow-sm: 0 2px 4px 0 rgba(15, 23, 42, 0.05);
  --shadow-md: 0 4px 8px -1px rgba(15, 23, 42, 0.08), 0 2px 4px -2px rgba(15, 23, 42, 0.04);
  --shadow-lg: 0 12px 24px -4px rgba(15, 23, 42, 0.08), 0 4px 6px -2px rgba(15, 23, 42, 0.03);
  --shadow-xl: 0 20px 32px -6px rgba(15, 23, 42, 0.12), 0 8px 12px -4px rgba(15, 23, 42, 0.04);

  /* 圆角 */
  --radius-sm: 6px;
  --radius-md: 10px;
  --radius-lg: 16px;
  --radius-xl: 20px;
  --radius-full: 9999px;

  /* 动画曲线 */
  --ease-spring: cubic-bezier(0.16, 1, 0.3, 1);
  --transition-fast: all 0.18s var(--ease-spring);
  --transition-base: all 0.25s var(--ease-spring);
}

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

body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
  background-color: #f6f8fb;
  color: var(--slate-800);
  line-height: 1.65;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

/* ================== 1. 顶部主导航栏 ================== */
.app-header {
  position: sticky;
  top: 0;
  z-index: 100;
  height: 72px;
  background: #ffffff;
  border-bottom: 1px solid rgba(226, 232, 240, 0.85);
  box-shadow: 0 2px 10px rgba(15, 23, 42, 0.03);
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0 32px;
}

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

.logo-icon {
  font-size: 24px;
  background: var(--primary-gradient);
  color: #ffffff;
  width: 44px;
  height: 44px;
  display: flex;
  align-items: center;
  justify-content: center;
  border-radius: 12px;
  box-shadow: var(--primary-glow);
}

.logo-text h1 {
  font-size: 17px;
  font-weight: 800;
  color: var(--slate-900);
  letter-spacing: -0.2px;
  line-height: 1.25;
}

.logo-text .sub-title {
  font-size: 12px;
  font-weight: 500;
  color: var(--slate-500);
}

/* 拟态段控制器导航 Tabs */
.nav-tabs {
  display: flex;
  background: var(--slate-100);
  padding: 5px;
  border-radius: var(--radius-md);
  border: 1px solid var(--slate-200);
  gap: 6px;
}

.nav-tab {
  display: flex;
  align-items: center;
  gap: 8px;
  padding: 8px 18px;
  font-size: 13.5px;
  font-weight: 600;
  color: var(--slate-600);
  background: transparent;
  border: none;
  border-radius: 8px;
  cursor: pointer;
  transition: var(--transition-fast);
  user-select: none;
}

.nav-tab:hover {
  color: var(--primary);
}

.nav-tab.active {
  background: #ffffff;
  color: var(--primary);
  font-weight: 700;
  box-shadow: var(--shadow-sm);
}

.badge {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 2px 7px;
  font-size: 11px;
  font-weight: 700;
  border-radius: var(--radius-full);
}

.mistake-count-badge {
  background: var(--danger-gradient);
  color: #ffffff;
  box-shadow: 0 2px 6px rgba(225, 29, 72, 0.3);
}

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

/* 数字化高级倒计时卡片 */
.timer-box {
  display: flex;
  align-items: center;
  gap: 10px;
  background: var(--slate-50);
  padding: 6px 16px;
  border-radius: 10px;
  border: 1px solid var(--slate-200);
  box-shadow: inset 0 1px 2px rgba(15, 23, 42, 0.04);
}

.timer-icon {
  font-size: 18px;
}

.timer-info {
  display: flex;
  flex-direction: column;
}

.timer-label {
  font-size: 11px;
  font-weight: 600;
  color: var(--slate-500);
  line-height: 1;
}

.timer-countdown {
  font-family: ui-monospace, SFMono-Regular, "SF Mono", Menlo, Consolas, monospace;
  font-size: 18px;
  font-weight: 800;
  color: var(--primary);
  letter-spacing: 0.8px;
}

.timer-box.warning {
  background: var(--warning-light);
  border-color: var(--warning-border);
}
.timer-box.warning .timer-countdown {
  color: var(--warning);
}

.timer-box.danger {
  background: var(--danger-light);
  border-color: var(--danger-border);
  animation: timerPulse 1.2s infinite ease-in-out;
}
.timer-box.danger .timer-countdown {
  color: var(--danger);
}

@keyframes timerPulse {
  0% { transform: scale(1); box-shadow: 0 0 0 0 rgba(225, 29, 72, 0.3); }
  50% { transform: scale(1.02); box-shadow: 0 0 0 4px rgba(225, 29, 72, 0.15); }
  100% { transform: scale(1); box-shadow: 0 0 0 0 rgba(225, 29, 72, 0.3); }
}

/* ================== 2. 通用高质感按钮 ================== */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  padding: 9px 18px;
  font-size: 13.5px;
  font-weight: 600;
  border-radius: 9px;
  cursor: pointer;
  border: 1px solid transparent;
  transition: var(--transition-fast);
  white-space: nowrap;
  user-select: none;
}

.btn:active:not(:disabled) {
  transform: scale(0.98);
}

.btn:disabled {
  opacity: 0.55;
  cursor: not-allowed;
}

.btn-primary {
  background: var(--primary-gradient);
  color: #ffffff;
  box-shadow: 0 3px 10px rgba(79, 70, 229, 0.28);
}
.btn-primary:hover:not(:disabled) {
  background: linear-gradient(135deg, #4338ca 0%, #4f46e5 100%);
  box-shadow: 0 6px 16px rgba(79, 70, 229, 0.35);
  transform: translateY(-1px);
}

.btn-success {
  background: var(--success-gradient);
  color: #ffffff;
  box-shadow: 0 3px 10px rgba(5, 150, 105, 0.25);
}
.btn-success:hover:not(:disabled) {
  background: linear-gradient(135deg, #047857 0%, #059669 100%);
  box-shadow: 0 6px 16px rgba(5, 150, 105, 0.35);
  transform: translateY(-1px);
}

.btn-danger {
  background: var(--danger-gradient);
  color: #ffffff;
  box-shadow: 0 3px 10px rgba(225, 29, 72, 0.25);
}
.btn-danger:hover:not(:disabled) {
  background: linear-gradient(135deg, #be123c 0%, #e11d48 100%);
  box-shadow: 0 6px 16px rgba(225, 29, 72, 0.35);
  transform: translateY(-1px);
}

.btn-outline {
  background: #ffffff;
  color: var(--slate-700);
  border-color: var(--slate-300);
}
.btn-outline:hover:not(:disabled) {
  background: var(--slate-50);
  border-color: var(--slate-400);
}

.btn-danger-outline {
  background: #ffffff;
  color: var(--danger);
  border-color: var(--danger-border);
}
.btn-danger-outline:hover:not(:disabled) {
  background: var(--danger-light);
}

.btn-outline-danger {
  background: transparent;
  color: var(--danger);
  border-color: var(--danger-border);
}
.btn-outline-danger:hover:not(:disabled) {
  background: var(--danger-light);
}

.btn-large {
  padding: 13px 32px;
  font-size: 15.5px;
  border-radius: 12px;
}

.btn-sm {
  padding: 5px 12px;
  font-size: 12px;
  border-radius: 6px;
}

.btn-block {
  width: 100%;
}

/* ================== 3. 页面容器 ================== */
.main-container {
  max-width: 1440px;
  margin: 0 auto;
  padding: 24px 32px;
  min-height: calc(100vh - 72px);
}

.tab-content {
  display: none;
}
.tab-content.active {
  display: block;
}

/* ================== 4. 欢迎/引导屏幕 (Hero + Rule Cards) ================== */
.welcome-screen {
  display: flex;
  justify-content: center;
  align-items: center;
  padding: 16px 0 32px;
}

.welcome-card {
  background: #ffffff;
  border-radius: var(--radius-xl);
  border: 1px solid var(--slate-200);
  box-shadow: var(--shadow-lg);
  padding: 44px 52px;
  max-width: 900px;
  width: 100%;
  position: relative;
  overflow: hidden;
}

.welcome-card::before {
  content: "";
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 5px;
  background: var(--primary-gradient);
}

.badge-tag {
  display: inline-block;
  background: var(--primary-light);
  color: var(--primary);
  border: 1px solid var(--primary-border);
  font-size: 12.5px;
  font-weight: 700;
  padding: 5px 14px;
  border-radius: var(--radius-full);
  margin-bottom: 16px;
}

.welcome-card h2 {
  font-size: 28px;
  font-weight: 800;
  color: var(--slate-900);
  letter-spacing: -0.4px;
  margin-bottom: 12px;
}

.welcome-desc {
  font-size: 15px;
  color: var(--slate-600);
  margin-bottom: 28px;
}

.rule-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 18px;
  margin-bottom: 28px;
}

.rule-card {
  background: #ffffff;
  border: 1px solid var(--slate-200);
  border-radius: 14px;
  padding: 22px 18px;
  text-align: center;
  box-shadow: var(--shadow-xs);
  transition: var(--transition-base);
  position: relative;
  overflow: hidden;
}

.rule-card::before {
  content: "";
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 3px;
  background: var(--cyan);
}

.rule-card.highlight::before {
  background: var(--primary-gradient);
}

.rule-card:nth-child(3)::before {
  background: var(--violet);
}

.rule-card:hover {
  transform: translateY(-3px);
  box-shadow: var(--shadow-md);
  border-color: var(--slate-300);
}

.rule-icon {
  font-size: 34px;
  margin-bottom: 10px;
}

.rule-title {
  font-size: 16px;
  font-weight: 700;
  color: var(--slate-800);
  margin-bottom: 6px;
}

.rule-count {
  font-size: 24px;
  font-weight: 800;
  color: var(--primary);
  margin-bottom: 4px;
  letter-spacing: -0.5px;
}

.rule-score {
  font-size: 13px;
  font-weight: 600;
  color: var(--slate-600);
  margin-bottom: 6px;
}

.rule-tip {
  font-size: 12px;
  color: var(--slate-500);
}

.rule-tip.text-danger {
  color: var(--danger);
  font-weight: 600;
}

/* 核心参数条 (仪表盘风) */
.exam-meta-box {
  display: flex;
  justify-content: space-around;
  background: var(--slate-50);
  border-radius: 14px;
  border: 1px solid var(--slate-200);
  padding: 18px 24px;
  margin-bottom: 28px;
}

.meta-item {
  display: flex;
  flex-direction: column;
  align-items: center;
}

.meta-label {
  font-size: 12px;
  font-weight: 600;
  color: var(--slate-500);
  margin-bottom: 4px;
}

.meta-val {
  font-size: 18px;
  font-weight: 800;
  color: var(--slate-900);
}

.text-success { color: var(--success) !important; }
.text-danger { color: var(--danger) !important; }
.text-primary { color: var(--primary) !important; }

.system-features-alert {
  background: linear-gradient(180deg, #f8fafc 0%, #f1f5f9 100%);
  border-left: 4px solid var(--primary);
  padding: 18px 22px;
  border-radius: 10px;
  margin-bottom: 32px;
}

.feat-title {
  font-size: 14px;
  font-weight: 700;
  color: var(--slate-800);
  margin-bottom: 8px;
}

.system-features-alert ul {
  padding-left: 20px;
  font-size: 13px;
  color: var(--slate-600);
  display: flex;
  flex-direction: column;
  gap: 7px;
}

.welcome-actions {
  display: flex;
  justify-content: center;
}

/* ================== 5. 考试工作台布局 (试卷 + 答题卡) ================== */
.exam-workspace {
  display: grid;
  grid-template-columns: 1fr 350px;
  gap: 28px;
  align-items: start;
}

.questions-section {
  display: flex;
  flex-direction: column;
  gap: 18px;
}

/* 粘性快捷筛选栏 (纯色硬件加速) */
.section-nav-sticky {
  position: sticky;
  top: 84px;
  z-index: 50;
  background: #ffffff;
  padding: 12px 20px;
  border-radius: var(--radius-md);
  border: 1px solid var(--slate-200);
  box-shadow: var(--shadow-sm);
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.section-chips {
  display: flex;
  gap: 8px;
}

.chip {
  padding: 6px 15px;
  font-size: 13px;
  font-weight: 600;
  color: var(--slate-600);
  background: var(--slate-100);
  border: 1px solid transparent;
  border-radius: var(--radius-full);
  cursor: pointer;
  transition: var(--transition-fast);
}

.chip:hover {
  background: var(--slate-200);
  color: var(--slate-900);
}

.chip.active {
  background: var(--primary-gradient);
  color: #ffffff;
  box-shadow: 0 2px 8px rgba(79, 70, 229, 0.25);
}

.filter-controls {
  display: flex;
  align-items: center;
  gap: 6px;
}

.filter-label {
  font-size: 13px;
  font-weight: 600;
  color: var(--slate-600);
}

/* 试题列表 */
.questions-list {
  display: flex;
  flex-direction: column;
  gap: 18px;
}

/* 单个试题卡片 (现代化微光卡片) */
.question-card {
  background: #ffffff;
  border-radius: var(--radius-lg);
  border: 1px solid var(--slate-200);
  box-shadow: var(--shadow-sm);
  padding: 24px 28px;
  position: relative;
  transition: border-color 0.2s, box-shadow 0.2s;
  content-visibility: auto;
  contain-intrinsic-size: 0 200px;
}

.question-card:hover {
  box-shadow: var(--shadow-md);
  border-color: var(--slate-300);
}

.question-card.highlight-focus {
  border-color: var(--primary);
  box-shadow: 0 0 0 3px rgba(79, 70, 229, 0.25);
}

.question-card-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 16px;
}

.q-header-left {
  display: flex;
  align-items: center;
  gap: 10px;
}

.q-number {
  font-size: 16px;
  font-weight: 800;
  color: var(--slate-900);
}

.q-badge {
  font-size: 12px;
  font-weight: 700;
  padding: 3px 9px;
  border-radius: 6px;
}

.badge-judge {
  background: var(--cyan-light);
  color: var(--cyan);
  border: 1px solid var(--cyan-border);
}
.badge-single {
  background: var(--warning-light);
  color: var(--warning);
  border: 1px solid var(--warning-border);
}
.badge-multiple {
  background: var(--violet-light);
  color: var(--violet);
  border: 1px solid var(--violet-border);
}

.q-score {
  font-size: 12px;
  font-weight: 600;
  color: var(--slate-500);
}

.btn-flag {
  background: #ffffff;
  border: 1px solid var(--slate-300);
  border-radius: 7px;
  padding: 5px 12px;
  font-size: 12.5px;
  font-weight: 600;
  color: var(--slate-600);
  cursor: pointer;
  display: flex;
  align-items: center;
  gap: 5px;
  transition: var(--transition-fast);
}

.btn-flag:hover {
  background: var(--warning-light);
  border-color: var(--warning-border);
  color: var(--warning);
}

.btn-flag.flagged {
  background: var(--warning-light);
  border-color: var(--warning);
  color: var(--warning);
  font-weight: 700;
  box-shadow: 0 2px 6px rgba(217, 119, 6, 0.2);
}

.q-stem {
  font-size: 16.5px;
  font-weight: 500;
  color: var(--slate-900);
  line-height: 1.7;
  margin-bottom: 20px;
  letter-spacing: 0.2px;
}

/* 选项区域 */
.options-grid {
  display: flex;
  flex-direction: column;
  gap: 11px;
}

/* 选项卡片 (Pill Option Card) */
.option-item {
  display: flex;
  align-items: flex-start;
  gap: 14px;
  padding: 13px 18px;
  background: var(--slate-50);
  border: 1px solid var(--slate-200);
  border-radius: 12px;
  cursor: pointer;
  transition: var(--transition-fast);
  user-select: none;
}

.option-item:hover {
  background: #fcfdff;
  border-color: var(--primary-border);
  transform: translateY(-1px);
}

.option-item.selected {
  background: #f8faff;
  border-color: var(--primary);
  box-shadow: 0 0 0 1.5px var(--primary);
}

.option-key {
  width: 28px;
  height: 28px;
  border-radius: 8px;
  background: #ffffff;
  border: 1px solid var(--slate-300);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 13px;
  font-weight: 700;
  color: var(--slate-700);
  flex-shrink: 0;
  transition: var(--transition-fast);
}

.option-item.selected .option-key {
  background: var(--primary-gradient);
  border-color: transparent;
  color: #ffffff;
  box-shadow: 0 2px 6px rgba(79, 70, 229, 0.35);
}

.option-text {
  font-size: 14.5px;
  color: var(--slate-800);
  line-height: 1.55;
  padding-top: 3px;
}

/* 判断题卡片组 */
.judge-options-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 16px;
}

.judge-btn {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 10px;
  padding: 16px;
  font-size: 16px;
  font-weight: 700;
  background: var(--slate-50);
  border: 1.5px solid var(--slate-200);
  border-radius: 12px;
  cursor: pointer;
  transition: var(--transition-fast);
}

.judge-btn:hover {
  background: #ffffff;
  border-color: var(--primary-border);
  transform: translateY(-1px);
}

.judge-btn.selected {
  background: var(--primary-light);
  border-color: var(--primary);
  color: var(--primary);
  box-shadow: 0 0 0 2px var(--primary);
  font-weight: 700;
}

/* 考后复盘状态 */
.question-card.result-correct {
  border-left: 5px solid var(--success);
}

.question-card.result-wrong {
  border-left: 5px solid var(--danger);
  background: #fffdfd;
}

.review-answer-panel {
  margin-top: 20px;
  padding-top: 16px;
  border-top: 1px dashed var(--slate-200);
  display: flex;
  flex-direction: column;
  gap: 12px;
}

.review-row {
  display: flex;
  align-items: center;
  flex-wrap: wrap;
  gap: 16px;
  font-size: 14px;
}

.ans-badge {
  font-weight: 700;
  padding: 3px 9px;
  border-radius: 6px;
}

.ans-correct { background: var(--success-light); color: var(--success); border: 1px solid var(--success-border); }
.ans-wrong { background: var(--danger-light); color: var(--danger); border: 1px solid var(--danger-border); }

.review-explanation {
  background: var(--slate-50);
  border-radius: 10px;
  padding: 14px 18px;
  font-size: 13.5px;
  color: var(--slate-700);
  line-height: 1.65;
  border: 1px solid var(--slate-200);
}

.review-explanation strong {
  color: var(--primary);
}

.option-item.opt-is-standard {
  background: var(--success-light) !important;
  border-color: var(--success) !important;
}
.option-item.opt-is-standard .option-key {
  background: var(--success-gradient) !important;
  color: #fff !important;
  border-color: transparent !important;
}

.option-item.opt-user-wrong {
  background: var(--danger-light) !important;
  border-color: var(--danger) !important;
}
.option-item.opt-user-wrong .option-key {
  background: var(--danger-gradient) !important;
  color: #fff !important;
  border-color: transparent !important;
}

/* ================== 6. 浮动答题卡面板 ================== */
.answer-sheet-aside {
  position: sticky;
  top: 84px;
  z-index: 40;
}

.sheet-card {
  background: #ffffff;
  border-radius: var(--radius-lg);
  border: 1px solid var(--slate-200);
  box-shadow: var(--shadow-md);
  padding: 20px;
  max-height: calc(100vh - 110px);
  display: flex;
  flex-direction: column;
}

.sheet-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 10px;
}

.sheet-title {
  font-size: 16px;
  font-weight: 800;
  color: var(--slate-900);
}

.sheet-progress-summary {
  font-size: 13.5px;
  font-weight: 800;
  color: var(--primary);
}

/* 新增平滑进度条 */
.sheet-progress-bar-wrap {
  width: 100%;
  height: 6px;
  background: var(--slate-100);
  border-radius: var(--radius-full);
  overflow: hidden;
  margin-bottom: 14px;
}

.sheet-progress-bar-fill {
  height: 100%;
  width: 0%;
  background: var(--primary-gradient);
  border-radius: var(--radius-full);
  transition: width 0.3s ease;
}

.sheet-legend {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  font-size: 11.5px;
  font-weight: 500;
  color: var(--slate-600);
  margin-bottom: 14px;
  padding-bottom: 12px;
  border-bottom: 1px solid var(--slate-200);
}

.legend-item {
  display: flex;
  align-items: center;
  gap: 5px;
}

.dot {
  width: 10px;
  height: 10px;
  border-radius: var(--radius-full);
}

.dot.unattempted { background: #ffffff; border: 1.5px solid var(--slate-300); }
.dot.answered { background: var(--primary); }
.dot.marked { background: var(--warning); }
.dot.correct { background: var(--success); }
.dot.wrong { background: var(--danger); }

.sheet-grid-wrapper {
  overflow-y: auto;
  flex: 1;
  padding-right: 4px;
}

.sheet-group {
  margin-bottom: 16px;
}

.sheet-group-title {
  display: flex;
  justify-content: space-between;
  font-size: 12.5px;
  font-weight: 700;
  color: var(--slate-700);
  margin-bottom: 10px;
}

.group-rate {
  font-size: 11.5px;
  font-weight: 600;
  color: var(--slate-400);
}

.sheet-buttons-grid {
  display: grid;
  grid-template-columns: repeat(10, 1fr);
  gap: 5px;
}

/* 答题卡小圆角方钮（适配三位数 001~190 等宽显示） */
.sheet-btn {
  aspect-ratio: 1;
  background: #ffffff;
  border: 1px solid var(--slate-300);
  border-radius: 6px;
  font-size: 10px;
  font-weight: 700;
  letter-spacing: -0.3px;
  font-variant-numeric: tabular-nums;
  color: var(--slate-700);
  display: flex;
  align-items: center;
  justify-content: center;
  cursor: pointer;
  transition: var(--transition-fast);
  position: relative;
}

.sheet-btn:hover {
  border-color: var(--primary);
  color: var(--primary);
  transform: scale(1.08);
}

.sheet-btn.answered {
  background: var(--primary);
  border-color: var(--primary);
  color: #ffffff;
  box-shadow: 0 2px 5px rgba(79, 70, 229, 0.25);
}

.sheet-btn.marked::after {
  content: "★";
  position: absolute;
  top: -4px;
  right: -2px;
  font-size: 10px;
  color: var(--warning);
}

.sheet-btn.correct {
  background: var(--success);
  border-color: var(--success);
  color: #ffffff;
  box-shadow: 0 2px 5px rgba(5, 150, 105, 0.25);
}

.sheet-btn.wrong {
  background: var(--danger);
  border-color: var(--danger);
  color: #ffffff;
  box-shadow: 0 2px 5px rgba(225, 29, 72, 0.25);
}

.sheet-footer {
  margin-top: 14px;
  padding-top: 14px;
  border-top: 1px solid var(--slate-200);
}

/* ================== 7. 错题本杂志级设计 ================== */
.mistakes-container {
  display: flex;
  flex-direction: column;
  gap: 24px;
}

.mistakes-header-panel {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 18px;
}

.mistakes-stat-card {
  background: #ffffff;
  border: 1px solid var(--slate-200);
  border-radius: 14px;
  padding: 22px;
  display: flex;
  flex-direction: column;
  align-items: center;
  box-shadow: var(--shadow-sm);
  cursor: pointer;
  transition: var(--transition-base);
  user-select: none;
  position: relative;
  overflow: hidden;
}

.mistakes-stat-card::before {
  content: "";
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 3px;
  background: var(--slate-300);
}

.mistakes-stat-card:hover {
  transform: translateY(-3px);
  border-color: var(--primary);
  box-shadow: var(--shadow-md);
}

.mistakes-stat-card.active {
  border-color: var(--primary);
  box-shadow: 0 0 0 2px var(--primary);
}

.mistakes-stat-card.primary::before {
  background: var(--danger-gradient);
}
.mistakes-stat-card:nth-child(2)::before {
  background: var(--cyan);
}
.mistakes-stat-card:nth-child(3)::before {
  background: var(--warning-gradient);
}
.mistakes-stat-card:nth-child(4)::before {
  background: var(--violet);
}

.mistakes-stat-card.primary .stat-number {
  color: var(--danger);
}

.stat-number {
  font-size: 32px;
  font-weight: 800;
  color: var(--slate-900);
  margin-bottom: 4px;
  letter-spacing: -0.5px;
}

.stat-desc {
  font-size: 13px;
  font-weight: 600;
  color: var(--slate-500);
}

.mistakes-action-bar {
  background: #ffffff;
  border: 1px solid var(--slate-200);
  border-radius: var(--radius-md);
  padding: 14px 20px;
  display: flex;
  justify-content: space-between;
  align-items: center;
  box-shadow: var(--shadow-sm);
}

.filter-tabs {
  display: flex;
  gap: 8px;
}

.tab-btn {
  padding: 6px 16px;
  font-size: 13px;
  font-weight: 600;
  color: var(--slate-600);
  background: var(--slate-100);
  border: 1px solid transparent;
  border-radius: var(--radius-full);
  cursor: pointer;
  transition: var(--transition-fast);
}

.tab-btn:hover {
  background: var(--slate-200);
  color: var(--slate-900);
}

.tab-btn.active {
  background: var(--slate-900);
  color: #ffffff;
}

.action-buttons {
  display: flex;
  gap: 10px;
}

.mistakes-list {
  display: flex;
  flex-direction: column;
  gap: 18px;
}

.mistake-card {
  background: #ffffff;
  border: 1px solid var(--slate-200);
  border-left: 5px solid var(--danger);
  border-radius: var(--radius-lg);
  padding: 24px 28px;
  box-shadow: var(--shadow-sm);
  display: flex;
  flex-direction: column;
  gap: 14px;
  content-visibility: auto;
  contain-intrinsic-size: 0 180px;
}

.mistake-card-top {
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.mistake-meta {
  display: flex;
  align-items: center;
  gap: 10px;
}

.mistake-badge-count {
  background: var(--danger-light);
  color: var(--danger);
  border: 1px solid var(--danger-border);
  font-size: 11.5px;
  font-weight: 700;
  padding: 3px 9px;
  border-radius: var(--radius-full);
}

.mistake-stem {
  font-size: 16.5px;
  font-weight: 600;
  color: var(--slate-900);
  line-height: 1.6;
}

.mistake-options {
  display: flex;
  flex-direction: column;
  gap: 9px;
}

.mistake-opt-item {
  display: flex;
  align-items: center;
  gap: 10px;
  font-size: 14px;
  padding: 8px 14px;
  border-radius: 8px;
  background: var(--slate-50);
}

.mistake-opt-item.is-correct {
  background: var(--success-light);
  color: var(--success);
  font-weight: 600;
  border: 1px solid var(--success-border);
}

.mistake-opt-item.is-user-wrong {
  background: var(--danger-light);
  color: var(--danger);
  font-weight: 600;
  border: 1px solid var(--danger-border);
}

.mistake-analysis-box {
  background: var(--slate-50);
  border-radius: 10px;
  padding: 14px 18px;
  font-size: 13.5px;
  color: var(--slate-700);
  line-height: 1.65;
  border: 1px solid var(--slate-200);
}

.mistake-card-footer {
  display: flex;
  justify-content: flex-end;
  gap: 10px;
  padding-top: 10px;
  border-top: 1px solid var(--slate-100);
}

.empty-state {
  background: #ffffff;
  border: 1px dashed var(--slate-300);
  border-radius: var(--radius-xl);
  padding: 64px 20px;
  text-align: center;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 14px;
}

.empty-icon {
  font-size: 52px;
}

.empty-state h3 {
  font-size: 19px;
  font-weight: 800;
  color: var(--slate-900);
}

.empty-state p {
  font-size: 14px;
  color: var(--slate-500);
  max-width: 440px;
}

/* ================== 8. 专项练习 ================== */
.practice-container {
  max-width: 880px;
  margin: 0 auto;
}

.practice-config-card {
  background: #ffffff;
  border: 1px solid var(--slate-200);
  border-radius: var(--radius-xl);
  padding: 38px 44px;
  box-shadow: var(--shadow-md);
}

.practice-config-card h2 {
  font-size: 24px;
  font-weight: 800;
  color: var(--slate-900);
  margin-bottom: 8px;
}

.practice-config-card .desc {
  font-size: 14.5px;
  color: var(--slate-600);
  margin-bottom: 28px;
}

.form-row {
  margin-bottom: 24px;
}

.form-row label {
  display: block;
  font-size: 14px;
  font-weight: 700;
  color: var(--slate-700);
  margin-bottom: 12px;
}

.chip-select {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
}

.practice-toolbar {
  display: flex;
  justify-content: space-between;
  align-items: center;
  background: #ffffff;
  padding: 14px 20px;
  border-radius: var(--radius-md);
  margin-bottom: 18px;
  border: 1px solid var(--slate-200);
  box-shadow: var(--shadow-sm);
}

.practice-questions-list {
  display: flex;
  flex-direction: column;
  gap: 18px;
}

/* ================== 9. 模态弹窗系统 (成绩单与确认) ================== */
.modal-overlay {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  background: rgba(15, 23, 42, 0.65);
  backdrop-filter: blur(5px);
  z-index: 200;
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 24px;
}

.modal-card {
  background: #ffffff;
  border-radius: var(--radius-xl);
  box-shadow: var(--shadow-xl);
  width: 100%;
  animation: modalScaleIn 0.28s var(--ease-spring);
}

@keyframes modalScaleIn {
  from { opacity: 0; transform: scale(0.92); }
  to { opacity: 1; transform: scale(1); }
}

/* 成绩报告弹窗 */
.score-card {
  max-width: 660px;
  padding: 38px 44px;
  text-align: center;
  position: relative;
  overflow: hidden;
}

.badge-status {
  display: inline-block;
  font-size: 14px;
  font-weight: 800;
  padding: 5px 16px;
  border-radius: var(--radius-full);
  margin-bottom: 12px;
}

.status-passed {
  background: var(--success-light);
  color: var(--success);
  border: 1px solid var(--success-border);
}
.status-failed {
  background: var(--danger-light);
  color: var(--danger);
  border: 1px solid var(--danger-border);
}

.score-title {
  font-size: 24px;
  font-weight: 800;
  color: var(--slate-900);
  margin-bottom: 24px;
}

.score-circle {
  margin: 0 auto 24px;
  width: 140px;
  height: 140px;
  border-radius: var(--radius-full);
  background: radial-gradient(circle at 50% 50%, #ffffff 0%, var(--primary-light) 100%);
  border: 5px solid var(--primary);
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  box-shadow: 0 10px 25px -4px rgba(79, 70, 229, 0.35);
}

.score-num {
  font-size: 44px;
  font-weight: 900;
  color: var(--primary);
  line-height: 1;
  letter-spacing: -1px;
}

.score-unit {
  font-size: 13px;
  font-weight: 700;
  color: var(--slate-500);
  margin-top: 4px;
}

.score-details-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 12px;
  background: var(--slate-50);
  border-radius: 12px;
  border: 1px solid var(--slate-200);
  padding: 16px;
  margin-bottom: 24px;
}

.detail-box {
  display: flex;
  flex-direction: column;
  align-items: center;
}

.detail-box .lbl {
  font-size: 12px;
  font-weight: 600;
  color: var(--slate-500);
}

.detail-box .val {
  font-size: 16px;
  font-weight: 800;
  color: var(--slate-900);
  margin-top: 2px;
}

.breakdown-table {
  width: 100%;
  border-collapse: collapse;
  margin-bottom: 28px;
  font-size: 13.5px;
}

.breakdown-table th {
  background: var(--slate-100);
  padding: 10px;
  color: var(--slate-700);
  font-weight: 700;
  border-bottom: 1px solid var(--slate-200);
}

.breakdown-table td {
  padding: 11px;
  border-bottom: 1px solid var(--slate-200);
  color: var(--slate-800);
}

.breakdown-table tr:hover td {
  background: var(--slate-50);
}

.score-actions {
  display: flex;
  justify-content: center;
  gap: 14px;
}

/* 确认提交弹窗 */
.confirm-card {
  max-width: 440px;
  padding: 32px 36px;
  text-align: center;
}

.confirm-icon {
  font-size: 46px;
  margin-bottom: 14px;
}

.confirm-card h3 {
  font-size: 19px;
  font-weight: 800;
  margin-bottom: 10px;
  color: var(--slate-900);
}

.confirm-card p {
  font-size: 14.5px;
  color: var(--slate-600);
  margin-bottom: 26px;
  line-height: 1.6;
}

.confirm-actions {
  display: flex;
  justify-content: center;
  gap: 14px;
}

/* 草稿恢复 Toast */
.draft-toast {
  position: fixed;
  bottom: 28px;
  right: 28px;
  z-index: 150;
  background: #ffffff;
  border-radius: 12px;
  box-shadow: var(--shadow-xl);
  border: 1px solid var(--primary-border);
  padding: 16px 22px;
  display: flex;
  align-items: center;
  gap: 18px;
  animation: slideUp 0.35s var(--ease-spring);
}

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

.draft-msg {
  font-size: 14px;
  font-weight: 600;
  color: var(--slate-800);
}

.draft-actions {
  display: flex;
  gap: 10px;
}

/* ================== 10. 打印模式优化 (@media print) ================== */
@media print {
  .app-header,
  .section-nav-sticky,
  .answer-sheet-aside,
  .mistakes-action-bar,
  .btn,
  .nav-tabs {
    display: none !important;
  }

  body, .main-container {
    background: #ffffff !important;
    padding: 0 !important;
  }

  .exam-workspace {
    display: block !important;
  }

  .question-card, .mistake-card {
    box-shadow: none !important;
    border: 1px solid #ddd !important;
    page-break-inside: avoid;
    margin-bottom: 20px;
  }
}

/* 响应式适配 */
@media (max-width: 1080px) {
  .exam-workspace {
    grid-template-columns: 1fr;
  }

  .answer-sheet-aside {
    position: static;
  }

  .sheet-card {
    max-height: none;
  }

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

  .mistakes-header-panel {
    grid-template-columns: repeat(2, 1fr);
  }
}

/* ==========================================================================
   多用户体系与历史答题记录 (Multi-User & Exam Records Design System)
   ========================================================================== */

/* 顶部学员身份胶囊徽章 */
.user-badge {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 6px 14px;
  background: rgba(255, 255, 255, 0.9);
  border: 1.5px solid var(--primary-border);
  border-radius: 9999px;
  cursor: pointer;
  transition: var(--transition-fast);
  box-shadow: 0 2px 6px rgba(79, 70, 229, 0.08);
}

.user-badge:hover {
  background: #ffffff;
  border-color: var(--primary);
  transform: translateY(-1px);
  box-shadow: 0 4px 12px rgba(79, 70, 229, 0.16);
}

.user-icon {
  font-size: 16px;
}

.user-name {
  font-size: 14px;
  font-weight: 700;
  color: var(--slate-800);
  max-width: 120px;
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}

.user-switch-tag {
  font-size: 11px;
  font-weight: 600;
  padding: 2px 6px;
  background: var(--primary-light);
  color: var(--primary);
  border-radius: 6px;
}

/* 答题记录视图容器 */
.records-container {
  max-width: 1200px;
  margin: 0 auto;
  padding: 10px 0 60px 0;
}

.records-header-panel {
  background: linear-gradient(135deg, #ffffff 0%, #f8faff 100%);
  border: 1px solid var(--slate-200);
  border-radius: 20px;
  padding: 28px 32px;
  margin-bottom: 24px;
  box-shadow: var(--shadow-sm);
}

.records-title-bar {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 24px;
}

.records-title-bar h2 {
  font-size: 22px;
  font-weight: 800;
  color: var(--slate-900);
  margin-bottom: 6px;
}

.records-title-bar .subtitle {
  font-size: 14px;
  color: var(--slate-500);
}

.highlight-user {
  font-weight: 700;
  color: var(--primary);
}

.records-stats-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 16px;
}

.rec-stat-card {
  display: flex;
  align-items: center;
  gap: 16px;
  padding: 18px 20px;
  background: #ffffff;
  border: 1px solid var(--slate-200);
  border-radius: 14px;
  box-shadow: 0 1px 3px rgba(0, 0, 0, 0.04);
}

.rec-stat-card .stat-icon {
  font-size: 28px;
  width: 52px;
  height: 52px;
  border-radius: 12px;
  background: var(--slate-50);
  display: flex;
  align-items: center;
  justify-content: center;
  flex-shrink: 0;
}

.rec-stat-card .stat-data {
  display: flex;
  flex-direction: column;
}

.rec-stat-card .stat-num {
  font-size: 26px;
  font-weight: 800;
  color: var(--slate-900);
  line-height: 1.2;
}

.rec-stat-card .stat-lbl {
  font-size: 13px;
  color: var(--slate-500);
  margin-top: 2px;
}

/* 工具栏 */
.records-toolbar {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 20px;
  padding: 4px 0;
}

.records-hint {
  font-size: 13px;
  color: var(--slate-500);
}

/* 记录列表卡片 */
.records-list {
  display: flex;
  flex-direction: column;
  gap: 16px;
}

.record-card {
  background: #ffffff;
  border: 1px solid var(--slate-200);
  border-radius: 16px;
  padding: 22px 26px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 20px;
  box-shadow: var(--shadow-sm);
  transition: var(--transition-fast);
}

.record-card:hover {
  border-color: var(--primary-border);
  box-shadow: var(--shadow-md);
  transform: translateY(-2px);
}

.record-card.passed {
  border-left: 6px solid var(--success);
}

.record-card.failed {
  border-left: 6px solid var(--danger);
}

.record-card-left {
  display: flex;
  align-items: center;
  gap: 22px;
}

.record-score-circle {
  width: 72px;
  height: 72px;
  border-radius: 18px;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  flex-shrink: 0;
}

.record-card.passed .record-score-circle {
  background: var(--success-light);
  color: var(--success);
  border: 1.5px solid var(--success-border);
}

.record-card.failed .record-score-circle {
  background: var(--danger-light);
  color: var(--danger);
  border: 1.5px solid var(--danger-border);
}

.record-score-num {
  font-size: 24px;
  font-weight: 800;
  line-height: 1;
}

.record-score-unit {
  font-size: 11px;
  font-weight: 600;
  margin-top: 3px;
}

.record-info-main h4 {
  font-size: 16px;
  font-weight: 700;
  color: var(--slate-800);
  margin-bottom: 6px;
  display: flex;
  align-items: center;
  gap: 8px;
}

.record-meta-line {
  display: flex;
  flex-wrap: wrap;
  gap: 14px;
  font-size: 13px;
  color: var(--slate-500);
  margin-bottom: 8px;
}

.record-breakdown-chips {
  display: flex;
  gap: 10px;
}

.breakdown-chip {
  font-size: 12px;
  padding: 3px 8px;
  border-radius: 6px;
  background: var(--slate-100);
  color: var(--slate-700);
}

.breakdown-chip strong {
  color: var(--primary);
}

.record-card-actions {
  display: flex;
  align-items: center;
  gap: 10px;
}

/* 空状态 */
.records-empty {
  text-align: center;
  padding: 60px 20px;
  background: #ffffff;
  border-radius: 18px;
  border: 1px dashed var(--slate-300);
}

.records-empty .empty-icon {
  font-size: 48px;
  margin-bottom: 12px;
}

.records-empty h3 {
  font-size: 18px;
  font-weight: 700;
  color: var(--slate-800);
  margin-bottom: 6px;
}

.records-empty p {
  font-size: 14px;
  color: var(--slate-500);
  margin-bottom: 20px;
}

/* ==================== 学员选择与切换弹窗 ==================== */
.user-modal-card {
  max-width: 580px;
  width: 90%;
  padding: 0;
  overflow: hidden;
}

.user-modal-header {
  display: flex;
  justify-content: space-between;
  align-items: flex-start;
  padding: 24px 28px;
  background: linear-gradient(135deg, #f8faff 0%, #ffffff 100%);
  border-bottom: 1px solid var(--slate-200);
}

.user-header-info {
  display: flex;
  gap: 14px;
}

.user-header-icon {
  font-size: 32px;
}

.user-header-info h3 {
  font-size: 18px;
  font-weight: 800;
  color: var(--slate-900);
  margin-bottom: 4px;
}

.user-header-info p {
  font-size: 13px;
  color: var(--slate-500);
  line-height: 1.4;
}

.modal-close-btn {
  background: none;
  border: none;
  font-size: 24px;
  color: var(--slate-400);
  cursor: pointer;
  line-height: 1;
  padding: 0;
}

.modal-close-btn:hover {
  color: var(--slate-700);
}

.user-modal-body {
  padding: 24px 28px;
}

.user-input-box {
  margin-bottom: 24px;
}

.user-input-box label {
  display: block;
  font-size: 13px;
  font-weight: 700;
  color: var(--slate-700);
  margin-bottom: 8px;
}

.user-input-group {
  display: flex;
  gap: 10px;
}

.user-input-group input {
  flex: 1;
  padding: 12px 16px;
  border: 1.5px solid var(--slate-200);
  border-radius: 10px;
  font-size: 15px;
  transition: var(--transition-fast);
}

.user-input-group input:focus {
  outline: none;
  border-color: var(--primary);
  box-shadow: 0 0 0 3px rgba(79, 70, 229, 0.15);
}

/* 同名冲突智能决策提示区 */
.duplicate-prompt-box {
  background: var(--warning-light);
  border: 1.5px solid var(--warning-border);
  border-radius: 12px;
  padding: 16px 18px;
  margin-bottom: 24px;
}

.duplicate-prompt-box .prompt-header {
  display: flex;
  align-items: center;
  gap: 10px;
  margin-bottom: 8px;
}

.duplicate-prompt-box .prompt-icon {
  font-size: 20px;
  line-height: 1;
}

.duplicate-prompt-box .prompt-title-wrap {
  display: flex;
  flex-direction: column;
}

.duplicate-prompt-box .prompt-title {
  font-size: 14px;
  font-weight: 700;
  color: var(--slate-900);
}

.duplicate-prompt-box .prompt-meta {
  font-size: 12px;
  color: var(--slate-600);
  margin-top: 2px;
}

.duplicate-prompt-box .prompt-desc {
  font-size: 12.5px;
  color: var(--slate-600);
  line-height: 1.5;
  margin-bottom: 12px;
}

.duplicate-prompt-box .prompt-actions {
  display: flex;
  gap: 10px;
  flex-wrap: wrap;
}

.existing-users-section .section-title {
  display: flex;
  justify-content: space-between;
  align-items: center;
  font-size: 13px;
  font-weight: 700;
  color: var(--slate-600);
  margin-bottom: 12px;
}

.user-count-tag {
  font-size: 12px;
  color: var(--slate-400);
  font-weight: normal;
}

.user-chips-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 10px;
  max-height: 240px;
  overflow-y: auto;
}

.user-chip-card {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 12px 14px;
  background: var(--slate-50);
  border: 1px solid var(--slate-200);
  border-radius: 10px;
  cursor: pointer;
  transition: var(--transition-fast);
}

.user-chip-card:hover {
  background: #ffffff;
  border-color: var(--primary-border);
  box-shadow: var(--shadow-sm);
  transform: translateY(-1px);
}

.user-chip-card.active {
  background: var(--primary-light);
  border-color: var(--primary);
  box-shadow: 0 0 0 1.5px var(--primary);
}

.user-chip-info {
  display: flex;
  flex-direction: column;
}

.user-chip-name {
  font-size: 14px;
  font-weight: 700;
  color: var(--slate-800);
}

.user-chip-meta {
  font-size: 11px;
  color: var(--slate-400);
  margin-top: 2px;
}

.btn-delete-user {
  background: none;
  border: none;
  color: var(--slate-400);
  font-size: 14px;
  cursor: pointer;
  padding: 4px;
  border-radius: 4px;
  transition: var(--transition-fast);
}

.btn-delete-user:hover {
  color: var(--danger);
  background: var(--danger-light);
}

/* ==================== 历史全卷试卷复盘大弹窗 ==================== */
.record-detail-card {
  max-width: 1000px;
  width: 95%;
  max-height: 90vh;
  display: flex;
  flex-direction: column;
  padding: 0;
  overflow: hidden;
}

.record-detail-header {
  display: flex;
  justify-content: space-between;
  align-items: flex-start;
  padding: 20px 28px;
  background: #ffffff;
  border-bottom: 1px solid var(--slate-200);
  flex-shrink: 0;
}

.detail-header-badges {
  display: flex;
  align-items: center;
  gap: 10px;
  margin-bottom: 6px;
}

.record-detail-header h2 {
  font-size: 20px;
  font-weight: 800;
  color: var(--slate-900);
}

.detail-meta-time {
  font-size: 13px;
  color: var(--slate-500);
}

.record-detail-summary-bar {
  display: flex;
  align-items: center;
  gap: 28px;
  padding: 14px 28px;
  background: var(--slate-50);
  border-bottom: 1px solid var(--slate-200);
  flex-shrink: 0;
}

.summary-score-box, .summary-rate-box {
  display: flex;
  flex-direction: column;
}

.summary-score-box .lbl, .summary-rate-box .lbl {
  font-size: 11px;
  color: var(--slate-500);
  font-weight: 600;
}

.score-val {
  font-size: 22px;
  font-weight: 800;
  color: var(--primary);
}

.score-val small {
  font-size: 12px;
  color: var(--slate-400);
}

.rate-val {
  font-size: 20px;
  font-weight: 800;
  color: var(--success);
}

.summary-breakdown-box {
  display: flex;
  gap: 16px;
  margin-left: auto;
}

.record-detail-toolbar {
  padding: 12px 28px;
  background: #ffffff;
  border-bottom: 1px solid var(--slate-200);
  flex-shrink: 0;
}

.record-detail-content {
  flex: 1;
  overflow-y: auto;
  padding: 24px 28px;
  display: flex;
  flex-direction: column;
  gap: 18px;
  background: var(--slate-50);
}


/* ==========================================================================
   移动端 (Mobile Responsive Design System for Chrome & Safari)
   ========================================================================== */

/* 桌面端隐藏移动端专属部件 */
.drawer-drag-bar {
  display: none;
}

.mobile-bottom-nav {
  display: none;
}

.mobile-sheet-fab {
  display: none;
}

.sheet-drawer-backdrop {
  display: none;
}

@media (max-width: 768px) {
  /* 1. 基础视口与防误触 */
  body {
    overscroll-behavior-y: contain;
    padding-bottom: 64px;
  }

  input, button, select, textarea {
    -webkit-tap-highlight-color: transparent;
    touch-action: manipulation;
  }

  .main-container {
    padding: 10px 12px 30px 12px;
  }

  /* 2. 顶部主导航栏紧凑化 */
  .app-header {
    height: 56px;
    padding: 0 12px;
  }

  .header-left {
    gap: 8px;
  }

  .logo-icon {
    width: 34px;
    height: 34px;
    font-size: 18px;
    border-radius: 8px;
  }

  .logo-text h1 {
    font-size: 14.5px;
    font-weight: 800;
    max-width: 140px;
    overflow: hidden;
    text-overflow: ellipsis;
    white-space: nowrap;
  }

  .logo-text .sub-title {
    display: none;
  }

  /* 顶部隐藏 Tab 切换，移至底部导航栏 */
  .app-header .nav-tabs {
    display: none !important;
  }

  .header-right {
    gap: 6px;
  }

  .user-badge {
    padding: 4px 8px;
    gap: 4px;
  }

  .user-name {
    max-width: 55px;
    font-size: 12px;
  }

  .user-switch-tag {
    display: none;
  }

  .timer-box {
    padding: 4px 8px;
    gap: 4px;
  }

  .timer-icon {
    font-size: 14px;
  }

  .timer-info .timer-label {
    display: none;
  }

  .timer-countdown {
    font-size: 13px;
    font-weight: 800;
  }

  #btnHeaderSubmit {
    padding: 6px 10px;
    font-size: 12px;
  }

  #btnHeaderSubmit span {
    display: none;
  }

  #btnRestartExam {
    padding: 6px 8px;
    font-size: 12px;
  }

  #btnRestartExam span {
    display: none;
  }

  /* 3. 移动端固定底部主导航栏 (Bottom Navigation Bar) */
  .mobile-bottom-nav {
    display: flex;
    position: fixed;
    bottom: 0;
    left: 0;
    right: 0;
    height: 56px;
    background: rgba(255, 255, 255, 0.96);
    backdrop-filter: blur(10px);
    -webkit-backdrop-filter: blur(10px);
    border-top: 1px solid var(--slate-200);
    z-index: 100;
    box-shadow: 0 -2px 10px rgba(0, 0, 0, 0.05);
    padding-bottom: env(safe-area-inset-bottom, 0px);
    justify-content: space-around;
    align-items: center;
  }

  .mobile-nav-item {
    flex: 1;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    gap: 2px;
    height: 100%;
    border: none;
    background: transparent;
    font-size: 11px;
    font-weight: 600;
    color: var(--slate-500);
    cursor: pointer;
    position: relative;
    -webkit-tap-highlight-color: transparent;
  }

  .mobile-nav-item.active {
    color: var(--primary);
    font-weight: 800;
  }

  .mobile-nav-item .m-icon {
    font-size: 20px;
    line-height: 1;
  }

  .mobile-nav-item .m-badge {
    position: absolute;
    top: 4px;
    right: calc(50% - 18px);
    background: var(--danger);
    color: #ffffff;
    font-size: 10px;
    font-weight: 700;
    padding: 1px 5px;
    border-radius: 999px;
    line-height: 1.2;
    box-shadow: 0 1px 3px rgba(225, 29, 72, 0.3);
  }

  /* 4. 考试工作台与移动端悬浮答题卡按钮 */
  .exam-workspace {
    display: block !important;
  }

  .mobile-sheet-fab {
    position: fixed;
    right: 16px;
    bottom: 72px;
    z-index: 110;
    display: inline-flex;
    align-items: center;
    gap: 6px;
    padding: 10px 16px;
    background: var(--primary-gradient);
    color: #ffffff;
    border: none;
    border-radius: 999px;
    box-shadow: 0 4px 16px rgba(79, 70, 229, 0.45);
    font-size: 13px;
    font-weight: 700;
    cursor: pointer;
    -webkit-tap-highlight-color: transparent;
    transition: transform 0.18s, box-shadow 0.18s;
  }

  .mobile-sheet-fab:active {
    transform: scale(0.94);
  }

  .mobile-sheet-fab .fab-badge {
    background: rgba(255, 255, 255, 0.25);
    padding: 2px 7px;
    border-radius: 999px;
    font-size: 11px;
    font-weight: 800;
  }

  /* 5. 移动端底部滑出式抽屉答题卡 (Bottom Sheet Drawer) */
  .answer-sheet-aside {
    position: fixed !important;
    top: auto !important;
    left: 0 !important;
    right: 0 !important;
    bottom: 0 !important;
    width: 100% !important;
    z-index: 130 !important;
    transform: translateY(105%);
    transition: transform 0.32s cubic-bezier(0.16, 1, 0.3, 1);
    pointer-events: none;
    margin: 0 !important;
    padding: 0 !important;
  }

  .answer-sheet-aside.drawer-open {
    transform: translateY(0);
    pointer-events: auto;
  }

  .sheet-drawer-backdrop {
    display: none;
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: rgba(15, 23, 42, 0.55);
    backdrop-filter: blur(4px);
    -webkit-backdrop-filter: blur(4px);
    z-index: 125;
  }

  .sheet-drawer-backdrop.active {
    display: block;
  }

  .answer-sheet-aside .sheet-card {
    border-radius: 20px 20px 0 0 !important;
    max-height: 80vh !important;
    display: flex;
    flex-direction: column;
    padding: 12px 16px 24px 16px !important;
    box-shadow: 0 -10px 35px rgba(0, 0, 0, 0.25) !important;
    border: 1px solid var(--slate-200);
    border-bottom: none !important;
    background: #ffffff;
  }

  .drawer-drag-bar {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 4px;
    padding-bottom: 8px;
    cursor: pointer;
    user-select: none;
  }

  .drag-handle {
    width: 36px;
    height: 4px;
    background: var(--slate-300);
    border-radius: 999px;
  }

  .drawer-close-text {
    font-size: 11px;
    font-weight: 600;
    color: var(--slate-400);
  }

  .sheet-grid-wrapper {
    flex: 1;
    overflow-y: auto;
    -webkit-overflow-scrolling: touch;
    max-height: 52vh;
  }

  .sheet-buttons-grid {
    grid-template-columns: repeat(8, 1fr) !important;
    gap: 5px !important;
  }

  .sheet-btn {
    font-size: 10px;
    border-radius: 6px;
  }

  /* 6. 粘性快捷筛选栏移动端自适应 */
  .section-nav-sticky {
    top: 56px !important;
    padding: 8px 10px !important;
    flex-direction: column;
    gap: 8px;
    align-items: stretch;
    border-radius: 8px;
  }

  .section-chips {
    overflow-x: auto;
    white-space: nowrap;
    -webkit-overflow-scrolling: touch;
    scrollbar-width: none;
    padding-bottom: 2px;
  }

  .section-chips::-webkit-scrollbar {
    display: none;
  }

  .filter-controls {
    justify-content: space-between;
    font-size: 12px;
  }

  /* 7. 试题与选项卡片紧凑排版 */
  .question-card {
    padding: 16px 14px;
    border-radius: 14px;
    gap: 12px;
  }

  .q-stem {
    font-size: 15px;
    line-height: 1.6;
    margin-bottom: 12px;
  }

  .option-item {
    padding: 11px 12px;
    gap: 10px;
    border-radius: 10px;
    font-size: 14px;
  }

  .option-key {
    width: 26px;
    height: 26px;
    font-size: 12px;
  }

  .option-text {
    font-size: 14px;
  }

  .judge-options-grid {
    gap: 10px;
  }

  .judge-btn {
    padding: 12px 10px;
    font-size: 15px;
  }

  /* 8. 欢迎界面自适应 */
  .welcome-card {
    padding: 22px 16px;
    border-radius: 16px;
  }

  .welcome-card h2 {
    font-size: 18px;
  }

  .welcome-desc {
    font-size: 13px;
  }

  .exam-meta-box {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 12px;
    padding: 14px;
  }

  .system-features-alert {
    padding: 12px 14px;
  }

  /* 9. 弹窗系统移动端全屏化与自适应 */
  .modal-overlay {
    padding: 8px;
  }

  .score-card {
    padding: 24px 16px;
    border-radius: 18px;
    max-height: 92vh;
    overflow-y: auto;
  }

  .score-circle {
    width: 96px;
    height: 96px;
    border-radius: 20px;
  }

  .score-number {
    font-size: 32px;
  }

  .user-modal-card {
    width: 100%;
    max-height: 92vh;
    border-radius: 18px;
  }

  .user-modal-header {
    padding: 18px 20px;
  }

  .user-modal-body {
    padding: 18px 20px;
  }

  .user-chips-grid {
    grid-template-columns: 1fr;
    max-height: 180px;
  }

  .duplicate-prompt-box .prompt-actions {
    flex-direction: column;
  }

  .record-detail-card {
    width: 100% !important;
    height: 100% !important;
    max-height: 100vh !important;
    border-radius: 0 !important;
  }

  .record-detail-header {
    padding: 14px 16px;
  }

  .record-detail-header h2 {
    font-size: 17px;
  }

  .record-detail-summary-bar {
    flex-direction: column;
    align-items: flex-start;
    gap: 10px;
    padding: 12px 16px;
  }

  .summary-breakdown-box {
    margin-left: 0;
    flex-wrap: wrap;
    gap: 8px;
  }

  .record-detail-toolbar {
    padding: 8px 12px;
    overflow-x: auto;
    white-space: nowrap;
    scrollbar-width: none;
  }

  .record-detail-toolbar .filter-tabs {
    flex-wrap: nowrap;
  }

  .record-detail-content {
    padding: 14px 12px;
    gap: 12px;
  }

  /* 10. 答题记录与错题本移动端网格优化 */
  .records-header-panel {
    padding: 18px 14px;
    border-radius: 14px;
  }

  .records-title-bar {
    flex-direction: column;
    align-items: flex-start;
    gap: 10px;
  }

  .records-stats-grid {
    grid-template-columns: repeat(2, 1fr);
    gap: 10px;
  }

  .rec-stat-card {
    padding: 12px;
    gap: 10px;
  }

  .rec-stat-card .stat-icon {
    width: 42px;
    height: 42px;
    font-size: 22px;
  }

  .rec-stat-card .stat-num {
    font-size: 20px;
  }

  .record-card {
    padding: 16px 14px;
    flex-direction: column;
    align-items: stretch;
    gap: 14px;
  }

  .record-card-actions {
    justify-content: flex-end;
    width: 100%;
  }

  .mistakes-header-panel {
    grid-template-columns: repeat(2, 1fr) !important;
    gap: 10px;
    padding: 16px 14px;
  }

  .mistakes-stat-card {
    padding: 14px;
  }

  .stat-number {
    font-size: 24px;
  }

  .mistakes-action-bar {
    flex-direction: column;
    gap: 10px;
    align-items: stretch;
    padding: 12px 14px;
  }

  .action-buttons {
    flex-direction: column;
    width: 100%;
  }

  .practice-config-card {
    padding: 22px 16px;
    border-radius: 16px;
  }

  .practice-config-card h2 {
    font-size: 20px;
  }
}