/* ============ 基础变量 / 主题 ============ */
:root {
  --bg: #f4f6fb;
  --bg-soft: #ffffff;
  --card: #ffffff;
  --card-2: #f8fafc;
  --text: #1e293b;
  --text-soft: #64748b;
  --text-mute: #94a3b8;
  --border: #e2e8f0;
  --primary: #4f46e5;
  --primary-soft: #eef2ff;
  --primary-dark: #4338ca;
  --green: #10b981;
  --green-soft: #ecfdf5;
  --red: #ef4444;
  --red-soft: #fef2f2;
  --amber: #f59e0b;
  --amber-soft: #fffbeb;
  --shadow: 0 1px 3px rgba(15, 23, 42, .06), 0 4px 16px rgba(15, 23, 42, .05);
  --shadow-lg: 0 8px 32px rgba(79, 70, 229, .18);
  --radius: 16px;
  --radius-sm: 10px;
}

[data-theme="dark"] {
  --bg: #0f172a;
  --bg-soft: #1e293b;
  --card: #1e293b;
  --card-2: #273449;
  --text: #e2e8f0;
  --text-soft: #94a3b8;
  --text-mute: #64748b;
  --border: #334155;
  --primary: #818cf8;
  --primary-soft: #312e81;
  --primary-dark: #a5b4fc;
  --green-soft: #064e3b;
  --red-soft: #450a0a;
  --amber-soft: #451a03;
  --shadow: 0 1px 3px rgba(0, 0, 0, .3);
}

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

html { -webkit-text-size-adjust: 100%; }

body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC",
    "Hiragino Sans GB", "Microsoft YaHei", "Helvetica Neue", Helvetica, Arial, sans-serif;
  background: var(--bg);
  color: var(--text);
  line-height: 1.7;
  min-height: 100vh;
  transition: background .3s ease, color .3s ease;
}

.hidden { display: none !important; }

/* ============ 顶部导航 ============ */
.topbar {
  position: sticky;
  top: 0;
  z-index: 50;
  background: var(--bg-soft);
  border-bottom: 1px solid var(--border);
  backdrop-filter: saturate(180%) blur(8px);
}
.topbar-inner {
  max-width: 1120px;
  margin: 0 auto;
  padding: 14px 20px;
  display: flex;
  align-items: center;
  justify-content: space-between;
}
.brand {
  display: flex;
  align-items: center;
  gap: 12px;
  cursor: pointer;
}
.brand-logo {
  font-size: 28px;
  width: 46px; height: 46px;
  display: grid; place-items: center;
  background: linear-gradient(135deg, var(--primary), #7c3aed);
  border-radius: 12px;
  box-shadow: var(--shadow-lg);
}
.brand-text strong { display: block; font-size: 16px; line-height: 1.2; }
.brand-text small { display: block; font-size: 12px; color: var(--text-soft); }
.topbar-actions { display: flex; gap: 10px; align-items: center; }
.btn-icon {
  border: 1px solid var(--border);
  background: var(--card);
  width: 40px; height: 40px;
  border-radius: 10px;
  font-size: 18px;
  cursor: pointer;
  transition: transform .15s ease, background .2s ease;
}
.btn-icon:hover { transform: translateY(-1px); background: var(--card-2); }

/* ============ 容器 ============ */
.container {
  max-width: 1120px;
  margin: 0 auto;
  padding: 24px 20px 80px;
}

/* ============ 屏幕切换 ============ */
.screen { display: none; animation: fade .35s ease; }
.screen.active { display: block; }
@keyframes fade { from { opacity: 0; transform: translateY(8px); } to { opacity: 1; transform: none; } }

/* ============ 首页 Hero ============ */
.hero { text-align: center; margin: 16px 0 28px; }
.hero h1 { font-size: 28px; font-weight: 800; letter-spacing: -.5px; }
.hero-sub { color: var(--text-soft); margin-top: 8px; }
.hero-sub b { color: var(--primary); }

/* ============ 卡片 ============ */
.card {
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 22px;
  margin-bottom: 18px;
  box-shadow: var(--shadow);
}
.card-head {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  margin-bottom: 16px;
}
.card-head h3 { font-size: 17px; font-weight: 700; }
.card-head .hint { font-size: 12px; color: var(--text-mute); }

/* ============ 统计卡片 ============ */
.stat-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(150px, 1fr));
  gap: 14px;
  margin-bottom: 18px;
}
.stat-box {
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  padding: 18px 16px;
  text-align: center;
  box-shadow: var(--shadow);
}
.stat-box .num { font-size: 26px; font-weight: 800; color: var(--primary); }
.stat-box .lbl { font-size: 13px; color: var(--text-soft); margin-top: 2px; }
.stat-box .tag {
  display: inline-block;
  font-size: 11px;
  padding: 2px 8px;
  border-radius: 20px;
  color: #fff;
  margin-bottom: 6px;
}

/* ============ 题型 chips ============ */
.type-chips { display: flex; flex-wrap: wrap; gap: 12px; }
.type-chip {
  flex: 1 1 140px;
  display: flex;
  align-items: center;
  gap: 10px;
  padding: 14px 16px;
  border: 2px solid var(--border);
  border-radius: var(--radius-sm);
  cursor: pointer;
  background: var(--card-2);
  transition: all .18s ease;
  user-select: none;
}
.type-chip:hover { border-color: var(--primary); }
.type-chip.active {
  border-color: var(--primary);
  background: var(--primary-soft);
}
.type-chip .chip-dot {
  width: 14px; height: 14px;
  border-radius: 50%;
  flex-shrink: 0;
}
.type-chip .chip-name { font-weight: 600; font-size: 14px; }
.type-chip .chip-count { margin-left: auto; font-size: 13px; color: var(--text-soft); }
.type-chip .check {
  width: 20px; height: 20px;
  border-radius: 6px;
  border: 2px solid var(--border);
  display: grid; place-items: center;
  font-size: 13px; color: #fff;
  background: transparent;
  flex-shrink: 0;
}
.type-chip.active .check { background: var(--primary); border-color: var(--primary); }

/* ============ 模式选择 ============ */
.mode-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(220px, 1fr)); gap: 14px; }
.mode-option { cursor: pointer; }
.mode-option input { display: none; }
.mode-card {
  border: 2px solid var(--border);
  border-radius: var(--radius-sm);
  padding: 20px;
  height: 100%;
  transition: all .18s ease;
  background: var(--card-2);
}
.mode-option input:checked + .mode-card {
  border-color: var(--primary);
  background: var(--primary-soft);
  box-shadow: 0 0 0 3px rgba(79, 70, 229, .12);
}
.mode-icon { font-size: 26px; }
.mode-title { font-size: 16px; font-weight: 700; margin: 6px 0 4px; }
.mode-desc { font-size: 13px; color: var(--text-soft); line-height: 1.5; }

/* ============ 开关选项 ============ */
.option-row { display: flex; flex-wrap: wrap; gap: 20px; }
.switch-label {
  display: flex; align-items: center; gap: 10px;
  cursor: pointer; user-select: none;
  font-size: 14px;
}
.switch-label input[type="checkbox"] {
  appearance: none;
  width: 42px; height: 24px;
  background: var(--border);
  border-radius: 20px;
  position: relative;
  cursor: pointer;
  transition: background .2s ease;
  flex-shrink: 0;
}
.switch-label input[type="checkbox"]::after {
  content: "";
  position: absolute;
  top: 3px; left: 3px;
  width: 18px; height: 18px;
  border-radius: 50%;
  background: #fff;
  transition: transform .2s ease;
}
.switch-label input[type="checkbox"]:checked { background: var(--primary); }
.switch-label input[type="checkbox"]:checked::after { transform: translateX(18px); }

/* ============ 按钮 ============ */
.btn-primary, .btn-ghost, .btn-link, .btn-mini {
  border: none;
  font-family: inherit;
  font-weight: 600;
  cursor: pointer;
  border-radius: var(--radius-sm);
  transition: all .18s ease;
}
.btn-primary {
  background: var(--primary);
  color: #fff;
  padding: 12px 26px;
  font-size: 15px;
  box-shadow: var(--shadow-lg);
}
.btn-primary:hover { background: var(--primary-dark); transform: translateY(-1px); }
.btn-primary:disabled { opacity: .5; cursor: not-allowed; transform: none; }
.btn-ghost {
  background: var(--card);
  color: var(--text);
  border: 1px solid var(--border);
  padding: 11px 20px;
  font-size: 14px;
}
.btn-ghost:hover { background: var(--card-2); border-color: var(--primary); }
.btn-large { width: 100%; padding: 16px; font-size: 17px; margin-top: 6px; }
.btn-link {
  background: transparent;
  color: var(--text-mute);
  font-size: 13px;
  padding: 8px;
  margin: 18px auto 0;
  display: block;
}
.btn-link:hover { color: var(--red); }
.btn-mini {
  background: transparent;
  color: var(--text-soft);
  font-size: 12px;
  padding: 4px 10px;
}

/* ============ 答题界面 ============ */
.progress-wrap { margin-bottom: 18px; }
.progress-bar {
  height: 8px;
  background: var(--border);
  border-radius: 10px;
  overflow: hidden;
}
.progress-fill {
  height: 100%;
  background: linear-gradient(90deg, var(--primary), #7c3aed);
  width: 0%;
  border-radius: 10px;
  transition: width .4s cubic-bezier(.4, 0, .2, 1);
}
.progress-meta {
  display: flex;
  justify-content: space-between;
  margin-top: 8px;
  font-size: 13px;
  color: var(--text-soft);
}
.score-live { color: var(--green); font-weight: 600; }

.quiz-body {
  display: grid;
  grid-template-columns: 1fr 260px;
  gap: 20px;
  align-items: start;
}

/* 题目卡片 */
.question-card {
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 26px;
  box-shadow: var(--shadow);
}
.q-meta {
  display: flex;
  align-items: center;
  gap: 10px;
  margin-bottom: 14px;
  flex-wrap: wrap;
}
.q-type-tag {
  font-size: 12px;
  font-weight: 700;
  color: #fff;
  padding: 3px 10px;
  border-radius: 20px;
}
.q-id { font-size: 13px; color: var(--text-mute); }
.q-text {
  font-size: 17px;
  font-weight: 600;
  line-height: 1.75;
  margin-bottom: 8px;
  word-break: break-word;
}
.q-image {
  max-width: 100%;
  border-radius: var(--radius-sm);
  margin: 12px 0 18px;
  border: 1px solid var(--border);
  cursor: zoom-in;
}
.q-image.big {
  position: fixed;
  inset: 0;
  z-index: 200;
  object-fit: contain;
  background: rgba(0,0,0,.85);
  margin: 0;
  border: none;
  border-radius: 0;
  cursor: zoom-out;
  padding: 30px;
  max-width: 100%;
}

/* 选项 */
.options { margin-top: 16px; display: flex; flex-direction: column; gap: 10px; }
.option {
  display: flex;
  align-items: flex-start;
  gap: 12px;
  padding: 14px 16px;
  border: 2px solid var(--border);
  border-radius: var(--radius-sm);
  cursor: pointer;
  transition: all .15s ease;
  background: var(--card-2);
  user-select: none;
}
.option:hover { border-color: var(--primary); background: var(--primary-soft); }
.option .opt-label {
  flex-shrink: 0;
  width: 30px; height: 30px;
  border-radius: 50%;
  border: 2px solid var(--border);
  display: grid; place-items: center;
  font-weight: 700;
  font-size: 14px;
  transition: all .15s ease;
}
.option .opt-text { padding-top: 3px; font-size: 15px; flex: 1; }

/* 选中态 */
.option.selected { border-color: var(--primary); background: var(--primary-soft); }
.option.selected .opt-label { background: var(--primary); color: #fff; border-color: var(--primary); }

/* 判题态 */
.option.correct { border-color: var(--green); background: var(--green-soft); }
.option.correct .opt-label { background: var(--green); color: #fff; border-color: var(--green); }
.option.wrong { border-color: var(--red); background: var(--red-soft); }
.option.wrong .opt-label { background: var(--red); color: #fff; border-color: var(--red); }
.option.disabled { cursor: default; }
.option.disabled:hover { border-color: var(--border); }

/* 判断题按钮 */
.judge-row { display: flex; gap: 14px; margin-top: 18px; }
.judge-btn {
  flex: 1;
  padding: 18px;
  border: 2px solid var(--border);
  border-radius: var(--radius-sm);
  background: var(--card-2);
  cursor: pointer;
  font-size: 16px;
  font-weight: 600;
  transition: all .15s ease;
  text-align: center;
}
.judge-btn:hover { border-color: var(--primary); }
.judge-btn.selected { border-color: var(--primary); background: var(--primary-soft); }
.judge-btn.correct { border-color: var(--green); background: var(--green-soft); color: var(--green); }
.judge-btn.wrong { border-color: var(--red); background: var(--red-soft); color: var(--red); }

/* 填空 */
.fill-blank {
  background: var(--card-2);
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  padding: 14px 16px;
  margin-top: 12px;
}
.fill-blank .fb-label { font-weight: 700; color: var(--primary); margin-right: 6px; }
.fill-blank .fb-prompt { font-size: 14px; color: var(--text-soft); display: block; margin-bottom: 8px; }
.fill-blank input {
  width: 100%;
  padding: 11px 14px;
  border: 2px solid var(--border);
  border-radius: 8px;
  font-size: 15px;
  font-family: inherit;
  background: var(--card);
  color: var(--text);
  transition: border-color .15s ease;
}
.fill-blank input:focus { outline: none; border-color: var(--primary); }
.fill-blank.ok { border-color: var(--green); background: var(--green-soft); }
.fill-blank.bad { border-color: var(--red); background: var(--red-soft); }
.fill-blank .fb-correct {
  font-size: 13px; color: var(--green); margin-top: 8px; font-weight: 600;
}
.fill-blank.bad .fb-correct { color: var(--red); }

/* 连线题（match） */
.match-options {
  background: var(--card-2);
  border: 1px solid var(--border);
  border-left: 4px solid var(--primary);
  border-radius: var(--radius-sm);
  padding: 12px 16px;
  margin-top: 16px;
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(180px, 1fr));
  gap: 6px 18px;
}
.match-opts-title {
  grid-column: 1 / -1;
  font-size: 12px;
  font-weight: 700;
  color: var(--text-soft);
  margin-bottom: 4px;
}
.match-opt { font-size: 14px; }
.match-opt b { color: var(--primary); margin-right: 4px; }
.match-items { margin-top: 6px; }
.match-blank { display: flex; align-items: center; flex-wrap: wrap; gap: 10px; }
.match-blank .fb-prompt { flex: 1; min-width: 120px; margin: 0; }
.match-blank input { max-width: 90px; text-transform: uppercase; text-align: center; font-weight: 700; }
.match-blank .fb-correct { width: 100%; }

/* 反馈区 */
.feedback {
  margin-top: 20px;
  padding: 16px 18px;
  border-radius: var(--radius-sm);
  font-size: 14px;
  animation: fade .3s ease;
}
.feedback.right { background: var(--green-soft); border: 1px solid var(--green); }
.feedback.wrong { background: var(--red-soft); border: 1px solid var(--red); }
.feedback-head { font-weight: 700; font-size: 15px; margin-bottom: 6px; display: flex; align-items: center; gap: 8px; }
.feedback.right .feedback-head { color: var(--green); }
.feedback.wrong .feedback-head { color: var(--red); }
.feedback .ans-line { margin: 4px 0; }
.feedback .analysis { margin-top: 8px; color: var(--text-soft); }
.feedback .analysis b { color: var(--text); }

/* 题号导航 */
.navigator {
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 18px;
  box-shadow: var(--shadow);
  position: sticky;
  top: 84px;
}
.navigator.collapsed .nav-grid, .navigator.collapsed .nav-legend { display: none; }
.nav-head {
  display: flex; justify-content: space-between; align-items: center;
  font-size: 13px; font-weight: 600; color: var(--text-soft);
  margin-bottom: 12px;
}
.nav-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(38px, 1fr));
  gap: 8px;
}
.nav-cell {
  aspect-ratio: 1;
  display: grid; place-items: center;
  border-radius: 8px;
  font-size: 13px;
  font-weight: 600;
  cursor: pointer;
  background: var(--card-2);
  border: 1px solid var(--border);
  transition: all .15s ease;
}
.nav-cell:hover { transform: scale(1.08); }
.nav-cell.done { background: var(--text-mute); color: #fff; border-color: transparent; }
.nav-cell.right { background: var(--green); color: #fff; border-color: transparent; }
.nav-cell.wrong { background: var(--red); color: #fff; border-color: transparent; }
.nav-cell.curr { outline: 2px solid var(--primary); outline-offset: 1px; }
.nav-legend {
  display: flex; flex-wrap: wrap; gap: 10px;
  margin-top: 14px; font-size: 11px; color: var(--text-soft);
}
.nav-legend span { display: flex; align-items: center; gap: 4px; }
.dot { width: 10px; height: 10px; border-radius: 3px; display: inline-block; }
.dot-done { background: var(--text-mute); }
.dot-right { background: var(--green); }
.dot-wrong { background: var(--red); }
.dot-curr { background: var(--card-2); border: 2px solid var(--primary); }

/* 底部操作 */
.quiz-actions {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-top: 22px;
  gap: 12px;
}
.action-center { display: flex; gap: 10px; }

/* ============ 结果界面 ============ */
.result-head {
  text-align: center;
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 36px 24px;
  box-shadow: var(--shadow);
  margin-bottom: 18px;
}
.result-emoji { font-size: 56px; }
.result-head h2 { font-size: 24px; margin: 6px 0; }
.result-score { margin: 14px 0 4px; }
.big-score { font-size: 56px; font-weight: 900; color: var(--primary); }
.big-total { font-size: 22px; color: var(--text-soft); }
.result-rate { color: var(--text-soft); font-size: 15px; }

.result-breakdown {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(140px, 1fr));
  gap: 14px;
  margin-bottom: 24px;
}
.bd-box {
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  padding: 18px;
  text-align: center;
  box-shadow: var(--shadow);
}
.bd-box .bd-tag {
  font-size: 12px; color: #fff; padding: 2px 10px; border-radius: 20px;
  display: inline-block; margin-bottom: 8px;
}
.bd-box .bd-nums { font-size: 22px; font-weight: 800; }
.bd-box .bd-nums .ok { color: var(--green); }
.bd-box .bd-rate { font-size: 13px; color: var(--text-soft); margin-top: 2px; }

.result-actions {
  display: flex; flex-wrap: wrap; gap: 12px; justify-content: center;
}

/* ============ Toast ============ */
.toast {
  position: fixed;
  bottom: 30px;
  left: 50%;
  transform: translateX(-50%) translateY(80px);
  background: var(--text);
  color: var(--bg);
  padding: 12px 22px;
  border-radius: 30px;
  font-size: 14px;
  font-weight: 600;
  box-shadow: var(--shadow-lg);
  opacity: 0;
  pointer-events: none;
  transition: all .3s ease;
  z-index: 300;
}
.toast.show { opacity: 1; transform: translateX(-50%) translateY(0); }

/* ============ 响应式 ============ */
@media (max-width: 860px) {
  .quiz-body { grid-template-columns: 1fr; }
  .navigator { position: static; }
  .nav-grid { grid-template-columns: repeat(auto-fill, minmax(34px, 1fr)); }
  .hero h1 { font-size: 24px; }
  .quiz-actions { flex-wrap: wrap; }
  .quiz-actions .btn-ghost { flex: 1; }
  .action-center { width: 100%; justify-content: center; order: -1; }
}
@media (max-width: 520px) {
  .container { padding: 16px 12px 60px; }
  .question-card { padding: 18px; }
  .q-text { font-size: 16px; }
  .brand-text small { display: none; }
  .topbar-inner { padding: 10px 14px; }
}