/* ============ 设计令牌 ============ */
:root {
  --bg: #0a0c12;
  --bg2: #0e1119;
  --card: #12161f;
  --card2: #181d29;
  --card3: #1f2534;
  --line: rgba(255, 255, 255, 0.07);
  --line2: rgba(255, 255, 255, 0.12);
  --text: #eef1f8;
  --muted: #9aa3b8;
  --faint: #5f6a85;
  --accent: #34d399;
  --accent2: #10b981;
  --accent-soft: rgba(52, 211, 153, 0.14);
  --on-accent: #06281d;
  --ok: #34d399;
  --ok-soft: rgba(52, 211, 153, 0.14);
  --bad: #f87171;
  --bad-soft: rgba(248, 113, 113, 0.14);
  --warn: #fbbf24;
  --warn-soft: rgba(251, 191, 36, 0.12);
  --shadow: 0 18px 44px rgba(0, 0, 0, 0.4);
  --shadow-sm: 0 6px 20px rgba(0, 0, 0, 0.28);
  --radius: 18px;
  --radius-sm: 12px;
  --font: -apple-system, BlinkMacSystemFont, "PingFang SC", "HarmonicOS Sans SC",
    "Microsoft YaHei", "Noto Sans SC", "Segoe UI", Roboto, sans-serif;
  --mono: "SF Mono", ui-monospace, "Cascadia Code", Consolas, monospace;
  --safe-b: env(safe-area-inset-bottom, 0px);
}
html[data-theme="light"] {
  --bg: #f4f6fb;
  --bg2: #eef1f8;
  --card: #ffffff;
  --card2: #f4f6fc;
  --card3: #e9edf6;
  --line: rgba(17, 24, 39, 0.08);
  --line2: rgba(17, 24, 39, 0.14);
  --text: #151a26;
  --muted: #5c6579;
  --faint: #97a0b5;
  --accent: #059669;
  --accent2: #10b981;
  --accent-soft: rgba(5, 150, 105, 0.1);
  --on-accent: #ffffff;
  --ok: #059669;
  --ok-soft: rgba(5, 150, 105, 0.1);
  --bad: #e04545;
  --bad-soft: rgba(224, 69, 69, 0.09);
  --warn: #d97706;
  --warn-soft: rgba(217, 119, 6, 0.1);
  --shadow: 0 18px 44px rgba(24, 32, 60, 0.12);
  --shadow-sm: 0 6px 18px rgba(24, 32, 60, 0.1);
}

* { box-sizing: border-box; margin: 0; padding: 0; -webkit-tap-highlight-color: transparent; }
html, body { height: 100%; }
body {
  font-family: var(--font);
  background:
    radial-gradient(900px 480px at 85% -10%, rgba(52, 211, 153, 0.13), transparent 60%),
    radial-gradient(700px 420px at -10% 110%, rgba(16, 185, 129, 0.09), transparent 55%),
    var(--bg);
  color: var(--text);
  transition: background 0.35s ease, color 0.35s ease;
  font-size: 15px;
  line-height: 1.6;
  overflow-x: hidden;
}
html[data-theme="light"] body {
  background:
    radial-gradient(900px 480px at 85% -10%, rgba(16, 185, 129, 0.09), transparent 60%),
    radial-gradient(700px 420px at -10% 110%, rgba(16, 185, 129, 0.06), transparent 55%),
    var(--bg);
}
button { font-family: inherit; color: inherit; background: none; border: none; cursor: pointer; }
input { font-family: inherit; }
/* 禁止移动端双击缩放（double-tap zoom） */
html, body { touch-action: manipulation; }
button, a, input, .mode-row, .opt, .sheet-cell, .search-item, .chip, .icon-btn, .mode-list, .options, .sheet-grid { touch-action: manipulation; }
::-webkit-scrollbar { width: 8px; height: 8px; }
::-webkit-scrollbar-thumb { background: var(--line2); border-radius: 8px; }
::selection { background: rgba(52, 211, 153, 0.35); }

/* ============ 布局 ============ */
#app { max-width: 720px; margin: 0 auto; padding: 0 16px calc(28px + var(--safe-b)); min-height: 100%; display: flex; flex-direction: column; }

#topbar {
  position: sticky; top: 0; z-index: 40;
  display: flex; align-items: center; gap: 10px;
  /* 负 margin 抵消 #app 的 16px 内边距：顶栏全宽出血占满屏幕 */
  margin: 0 -16px;
  padding: calc(14px + env(safe-area-inset-top, 0px)) 18px 10px;
  background: linear-gradient(var(--bg) 82%, transparent);
  backdrop-filter: blur(10px);
  -webkit-backdrop-filter: blur(10px);
}
.brand { font-size: 16.5px; font-weight: 800; letter-spacing: 0.3px; flex: 1; white-space: nowrap; }
.top-spacer { flex: 1; }
.brand-grad {
  background: linear-gradient(92deg, var(--accent), var(--accent2));
  -webkit-background-clip: text; background-clip: text; color: transparent;
}

main { flex: 1; }
.view { display: none; animation: fadeUp 0.28s cubic-bezier(0.22, 1, 0.36, 1); }
.view.active { display: block; }
@keyframes fadeUp { from { opacity: 0; } to { opacity: 1; } }

/* ============ 通用组件 ============ */
.icon-btn {
  width: 38px; height: 38px; border-radius: 12px;
  display: inline-flex; align-items: center; justify-content: center;
  background: var(--card2); border: 1px solid var(--line);
  color: var(--muted); flex: none;
  transition: transform 0.15s ease, color 0.15s ease, background 0.15s ease;
}
.icon-btn:active { transform: scale(0.9); }
.icon-btn.on { color: var(--warn); }
.icon-btn.danger { color: var(--bad); }
.icon-btn svg { width: 18px; height: 18px; }

.card {
  background: var(--card);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  box-shadow: var(--shadow-sm);
}
.card-pad { padding: 18px; }

.section-title {
  display: flex; align-items: center; justify-content: space-between;
  font-size: 13px; font-weight: 700; letter-spacing: 0.5px;
  color: var(--muted); margin: 22px 4px 10px;
}
.section-title .more { color: var(--accent); font-weight: 600; font-size: 12.5px; }

.btn {
  display: inline-flex; align-items: center; justify-content: center; gap: 8px;
  padding: 11px 18px; border-radius: 14px; font-size: 14.5px; font-weight: 700;
  background: var(--card2); border: 1px solid var(--line2);
  transition: transform 0.14s ease, filter 0.14s ease, background 0.2s ease;
  user-select: none;
}
.btn svg { width: 16px; height: 16px; flex: none; }
.btn:active { transform: scale(0.96); }
.btn-primary {
  background: linear-gradient(135deg, var(--accent), var(--accent2));
  color: var(--on-accent);
  border: none; box-shadow: 0 8px 22px rgba(16, 185, 129, 0.32);
}
.btn-primary:active { filter: brightness(1.1); }
.btn-ghost { background: transparent; border-color: var(--line); color: var(--muted); }
.btn:disabled { opacity: 0.45; pointer-events: none; }
.btn-block { width: 100%; }

.chip {
  display: inline-flex; align-items: center; gap: 6px;
  padding: 8px 14px; border-radius: 999px; font-size: 13px; font-weight: 600;
  background: var(--card2); border: 1px solid var(--line);
  color: var(--muted); transition: all 0.16s ease; user-select: none;
}
.chip svg { width: 15px; height: 15px; flex: none; }
.chip:active { transform: scale(0.95); }
.chip.on {
  background: var(--accent-soft); border-color: var(--accent);
  color: var(--accent); font-weight: 700;
}
.chip .num { font-size: 11px; opacity: 0.75; font-weight: 600; }

.pill {
  display: inline-flex; align-items: center; gap: 4px;
  padding: 3px 10px; border-radius: 999px;
  font-size: 11.5px; font-weight: 700; letter-spacing: 0.4px;
}
.pill svg { width: 12px; height: 12px; }
.pill-single { background: var(--accent-soft); color: var(--accent); }
.pill-multi { background: var(--warn-soft); color: var(--warn); }
.pill-judge { background: var(--ok-soft); color: var(--ok); }
.pill-diff { background: var(--card3); color: var(--muted); border: 1px solid var(--line); }

/* ============ 首页 ============ */
.hero {
  position: relative; overflow: hidden;
  padding: 22px 20px 20px;
  background:
    linear-gradient(145deg, rgba(109, 124, 255, 0.16), rgba(167, 139, 250, 0.05)),
    var(--card);
  border: 1px solid var(--line);
  border-radius: 22px;
}
.hero::after {
  content: ""; position: absolute; right: -50px; top: -60px; width: 200px; height: 200px;
  border-radius: 50%; background: radial-gradient(circle, rgba(52, 211, 153, 0.22), transparent 65%);
  pointer-events: none;
}
.hero-top { display: flex; justify-content: space-between; align-items: flex-start; gap: 12px; }
.hero-title { font-size: 20px; font-weight: 800; letter-spacing: 0.4px; }
.hero-sub { font-size: 12.5px; color: var(--muted); margin-top: 3px; }
.hero-badge {
  font-size: 11px; font-weight: 700; color: var(--accent);
  background: var(--accent-soft); border: 1px solid var(--accent);
  padding: 4px 10px; border-radius: 999px; white-space: nowrap;
}
.hero-stats { display: flex; gap: 10px; margin-top: 18px; flex-wrap: wrap; }
.stat-block {
  flex: 1; min-width: 72px; text-align: center;
  background: rgba(255, 255, 255, 0.03);
  border: 1px solid var(--line); border-radius: 14px; padding: 10px 6px;
}
html[data-theme="light"] .stat-block { background: rgba(17, 24, 39, 0.02); }
.stat-num { font-size: 20px; font-weight: 800; line-height: 1.2; }
.stat-num.grad { background: linear-gradient(92deg, var(--accent), var(--accent2)); -webkit-background-clip: text; background-clip: text; color: transparent; }
.stat-num.ok { color: var(--ok); }
.stat-num.bad { color: var(--bad); }
.stat-label { font-size: 11px; color: var(--faint); margin-top: 2px; font-weight: 600; letter-spacing: 0.3px; }

.progress-track { height: 6px; border-radius: 6px; background: var(--card3); overflow: hidden; margin-top: 16px; }
.progress-fill {
  height: 100%; width: 0%;
  background: linear-gradient(90deg, var(--accent), var(--accent2));
  border-radius: 6px; transition: width 0.6s cubic-bezier(0.22, 1, 0.36, 1);
}

.mode-list { display: flex; flex-direction: column; gap: 10px; }
.mode-row {
  display: flex; align-items: center; gap: 14px;
  padding: 13px 16px;
  background: var(--card); border: 1px solid var(--line);
  border-radius: 16px; text-align: left; width: 100%;
  transition: transform 0.15s ease, border-color 0.15s ease, box-shadow 0.15s ease;
}
.mode-row:active { transform: scale(0.985); }
html:not([data-theme="light"]) .mode-row { box-shadow: var(--shadow-sm); }
.row-i {
  flex: none; width: 44px; height: 44px; border-radius: 13px;
  display: flex; align-items: center; justify-content: center;
}
.row-i svg { width: 22px; height: 22px; }
.row-i.g { background: var(--accent-soft); color: var(--accent); }
.row-i.o { background: var(--ok-soft); color: var(--ok); }
.row-i.w { background: var(--warn-soft); color: var(--warn); }
.row-i.r { background: var(--bad-soft); color: var(--bad); }
.row-i.p { background: var(--card3); color: var(--muted); }
.row-t { flex: 1; min-width: 0; display: flex; flex-direction: column; }
.row-t .tt { font-size: 15px; font-weight: 750; letter-spacing: 0.2px; }
.row-t .dd { font-size: 12px; color: var(--faint); margin-top: 1px; white-space: nowrap; overflow: hidden; text-overflow: ellipsis; }
.mode-row .cnt {
  flex: none; font-size: 12px; font-weight: 700; color: var(--faint);
  background: var(--card2); border: 1px solid var(--line);
  border-radius: 999px; padding: 3px 11px; white-space: nowrap;
}
.mode-row .chev { flex: none; color: var(--faint); }
.mode-row .chev svg { width: 17px; height: 17px; }

.sub-panel {
  margin-top: 10px; padding: 14px;
  background: var(--card2); border: 1px solid var(--line);
  border-radius: 16px;
}
.chip-row { display: flex; flex-wrap: wrap; gap: 8px; }

.resume-bar {
  display: flex; align-items: center; gap: 12px;
  padding: 14px 16px; border-radius: 16px;
  background: linear-gradient(120deg, var(--accent-soft), transparent 80%);
  border: 1px solid var(--accent);
  margin-top: 12px;
}
.resume-bar .t { font-size: 13.5px; font-weight: 700; }
.resume-bar .d { font-size: 11.5px; color: var(--muted); }
.resume-btn { margin-left: auto; }

/* ============ 刷题页 ============ */
.quiz-top {
  display: flex; align-items: center; gap: 8px;
  margin-bottom: 14px;
}
.quiz-progress {
  flex: 1; font-size: 12.5px; font-weight: 700; color: var(--muted);
  display: flex; align-items: baseline; gap: 4px;
}
.quiz-progress b { color: var(--text); font-size: 14px; }

.quiz-bar { height: 4px; border-radius: 4px; background: var(--card3); overflow: hidden; margin-bottom: 18px; }
.quiz-bar-fill { height: 100%; width: 0%; background: linear-gradient(90deg, var(--accent), var(--accent2)); border-radius: 4px; transition: width 0.5s cubic-bezier(0.22, 1, 0.36, 1); }

.q-card { padding: 20px 18px 16px; }
.q-meta { display: flex; align-items: center; gap: 8px; margin-bottom: 12px; flex-wrap: wrap; }
.q-text {
  font-size: 17px; font-weight: 650; line-height: 1.75; letter-spacing: 0.2px;
  padding: 4px 0 2px;
}
.q-tip-strip {
  display: none;
  margin-top: 12px; padding: 10px 14px;
  background: var(--warn-soft); border: 1px solid rgba(251, 191, 36, 0.3);
  border-radius: 12px; font-size: 12.5px; color: var(--text); line-height: 1.7;
}
.q-tip-strip.show { display: block; animation: fadeUp 0.25s ease; }
.q-tip-strip .lb { font-weight: 800; color: var(--warn); margin-right: 6px; }

.options { margin-top: 16px; display: flex; flex-direction: column; gap: 10px; }
.opt {
  display: flex; align-items: center; gap: 12px;
  padding: 14px 14px;
  background: var(--card2);
  border: 1.5px solid var(--line);
  border-radius: 15px;
  text-align: left; font-size: 15px; line-height: 1.55;
  transition: transform 0.13s ease, background 0.2s ease, border-color 0.2s ease;
  position: relative;
}
.opt:active { transform: scale(0.985); }
.opt .k {
  flex: none; width: 30px; height: 30px; border-radius: 10px;
  display: inline-flex; align-items: center; justify-content: center;
  font-weight: 800; font-size: 13.5px;
  background: var(--card3); color: var(--muted);
  transition: all 0.2s ease;
}
.opt .v { flex: 1; }
.opt .mk { flex: none; font-size: 17px; opacity: 0; transition: opacity 0.2s ease; }
.opt.selected { border-color: var(--accent); background: var(--accent-soft); }
.opt.selected .k { background: var(--accent); color: #fff; }
.opt.right { border-color: var(--ok); background: var(--ok-soft); }
.opt.right .k { background: var(--ok); color: #fff; }
.opt.right .mk { opacity: 1; color: var(--ok); }
.opt.wrong { border-color: var(--bad); background: var(--bad-soft); }
.opt.wrong .k { background: var(--bad); color: #fff; }
.opt.wrong .mk { opacity: 1; color: var(--bad); }
.opt.dim { opacity: 0.45; }
.opt.correct-mark { border-color: var(--ok); border-style: dashed; }
.opt.correct-mark .k { background: var(--ok); color: #fff; }
.opt.multi-toggle.selected .mk { opacity: 1; color: var(--accent); }

.confirm-row { margin-top: 14px; display: flex; gap: 10px; }

.result-panel {
  display: none;
  margin-top: 16px; padding: 16px;
  border-radius: 16px; border: 1px solid var(--line);
  animation: fadeUp 0.3s cubic-bezier(0.22, 1, 0.36, 1);
}
.result-panel.show { display: block; }
.result-panel.correct { background: var(--ok-soft); border-color: rgba(52, 211, 153, 0.35); }
.result-panel.wrong { background: var(--bad-soft); border-color: rgba(248, 113, 113, 0.35); }
.result-head { display: flex; align-items: center; gap: 10px; font-size: 16px; font-weight: 800; }
.result-head .big { font-size: 22px; }
.result-head .sub { font-size: 12.5px; color: var(--muted); font-weight: 600; margin-left: auto; }
.result-tip {
  margin-top: 12px; padding: 10px 13px;
  background: var(--card);
  border-radius: 10px; font-size: 12.8px; line-height: 1.75;
}
.result-ana {
  margin-top: 12px; padding: 12px 13px;
  background: var(--card); border-radius: 10px;
  font-size: 13px; line-height: 1.8; color: var(--muted);
}
.result-ana .lb { font-weight: 800; color: var(--text); margin-right: 6px; }
.result-actions { display: flex; gap: 10px; margin-top: 14px; }

.nav-row { display: flex; gap: 10px; margin-top: 16px; }
.nav-row .btn { flex: 1; }

.kbd-hint {
  margin-top: 18px; text-align: center;
  font-size: 11.5px; color: var(--faint); letter-spacing: 0.4px;
}
.kbd-hint kbd {
  font-family: var(--mono); font-size: 10.5px; color: var(--muted);
  background: var(--card2); border: 1px solid var(--line2); border-bottom-width: 2px;
  border-radius: 5px; padding: 1px 6px; margin: 0 1px;
}
@media (max-width: 640px) { .kbd-hint { display: none; } }

/* 多选确认悬浮 */
.fab-confirm {
  position: fixed; left: 50%; bottom: calc(20px + var(--safe-b));
  transform: translateX(-50%) translateY(80px);
  z-index: 60; display: flex; gap: 10px;
  transition: transform 0.3s cubic-bezier(0.22, 1, 0.36, 1), opacity 0.3s;
  opacity: 0; pointer-events: none;
}
.fab-confirm.show { transform: translateX(-50%) translateY(0); opacity: 1; pointer-events: auto; }

/* ============ 答题卡 ============ */
.sheet-head { display: flex; align-items: center; gap: 8px; margin-bottom: 12px; }
.legend { display: flex; flex-wrap: wrap; gap: 12px; font-size: 11.5px; color: var(--muted); margin: 12px 2px 4px; }
.legend i { display: inline-block; width: 11px; height: 11px; border-radius: 4px; margin-right: 5px; vertical-align: -1px; }
.sheet-grid {
  display: grid; grid-template-columns: repeat(auto-fill, minmax(46px, 1fr));
  gap: 8px; margin-top: 14px;
}
.sheet-cell {
  aspect-ratio: 1; border-radius: 12px;
  background: var(--card2); border: 1px solid var(--line);
  color: var(--faint); font-size: 12.5px; font-weight: 700;
  display: flex; align-items: center; justify-content: center;
  transition: transform 0.12s ease;
  position: relative;
}
.sheet-cell:active { transform: scale(0.88); }
.sheet-cell.ok { background: var(--ok-soft); border-color: rgba(52, 211, 153, 0.4); color: var(--ok); }
.sheet-cell.wrong { background: var(--bad-soft); border-color: rgba(248, 113, 113, 0.4); color: var(--bad); }
.sheet-cell.fav { box-shadow: inset 0 0 0 2px var(--warn); }
.sheet-cell.current { outline: 2px solid var(--accent); outline-offset: 1px; }
.sheet-cell.mastered { box-shadow: inset 0 0 0 2px rgba(52, 211, 153, 0.6); }
.sheet-cell.empty-note { font-size: 10px; }

/* ============ 技巧页 ============ */
.tips-intro {
  padding: 22px 20px;
  background: linear-gradient(150deg, var(--accent-soft), transparent 70%), var(--card);
  border: 1px solid var(--line); border-radius: 22px;
}
.tips-intro h2 { font-size: 21px; font-weight: 800; letter-spacing: 0.4px; }
.tips-intro p { font-size: 13px; color: var(--muted); margin-top: 6px; line-height: 1.8; }

.tip-card {
  padding: 16px 18px; margin-bottom: 10px;
  background: var(--card); border: 1px solid var(--line);
  border-radius: 16px;
}
.tip-card .h { display: flex; align-items: center; gap: 10px; font-size: 15px; font-weight: 750; }
.tip-card .h .no {
  flex: none; width: 26px; height: 26px; border-radius: 9px;
  background: var(--accent-soft); color: var(--accent);
  display: inline-flex; align-items: center; justify-content: center;
  font-size: 12.5px; font-weight: 800;
}
.tip-card .bd { font-size: 13.5px; color: var(--muted); margin-top: 10px; line-height: 1.85; padding-left: 36px; }
.tip-card .bd b, .tip-card .bd strong { color: var(--text); }
.tip-card .bd .hl { color: var(--accent); font-weight: 700; }
.tip-card .bd .hl-w { color: var(--warn); font-weight: 700; }

.rule-table { width: 100%; border-collapse: collapse; font-size: 13px; }
.rule-table th {
  text-align: left; font-size: 11.5px; color: var(--faint);
  font-weight: 700; letter-spacing: 0.4px; padding: 8px 10px;
  border-bottom: 1px solid var(--line2);
}
.rule-table td { padding: 10px; border-bottom: 1px solid var(--line); vertical-align: top; }
.rule-table tr:last-child td { border-bottom: none; }
.rule-table td.w { font-weight: 700; }
.rule-table td .rate-b { font-size: 12px; font-weight: 800; color: var(--ok); white-space: nowrap; }
.rule-table td .rate-w { font-size: 12px; font-weight: 800; color: var(--bad); white-space: nowrap; }
.rule-table td .n { font-size: 11.5px; color: var(--faint); }

.module-chips { display: flex; flex-wrap: wrap; gap: 8px; margin-top: 6px; }
.module-chips .chip { background: var(--card2); }

.tips-note { font-size: 11.5px; color: var(--faint); text-align: center; margin-top: 18px; line-height: 1.8; }

/* ============ 统计页 ============ */
.stats-grid { display: grid; grid-template-columns: repeat(2, 1fr); gap: 10px; }
.stat-card { padding: 16px; }
.stat-card .v { font-size: 26px; font-weight: 800; }
.stat-card .l { font-size: 12px; color: var(--faint); margin-top: 2px; font-weight: 600; }
.bar-row { margin-bottom: 12px; }
.bar-row .lab { display: flex; justify-content: space-between; font-size: 12.5px; margin-bottom: 5px; }
.bar-row .lab b { font-weight: 700; }
.bar-row .tr { height: 6px; border-radius: 6px; background: var(--card3); overflow: hidden; }
.bar-row .fl { height: 100%; border-radius: 6px; background: linear-gradient(90deg, var(--accent), var(--accent2)); }

/* ============ 搜索 ============ */
.search-box {
  display: flex; align-items: center; gap: 10px;
  padding: 4px 14px; background: var(--card);
  border: 1px solid var(--line2); border-radius: 14px;
}
.search-box svg { width: 17px; height: 17px; color: var(--faint); flex: none; }
.search-box input {
  flex: 1; background: none; border: none; outline: none;
  color: var(--text); font-size: 15px; padding: 12px 0;
}
.search-box input::placeholder { color: var(--faint); }
.search-results { margin-top: 14px; display: flex; flex-direction: column; gap: 8px; }
.search-item {
  padding: 14px 16px; text-align: left;
  background: var(--card); border: 1px solid var(--line);
  border-radius: 14px; font-size: 13.5px; line-height: 1.7;
  transition: transform 0.13s ease;
}
.search-item:active { transform: scale(0.98); }
.search-item .q { color: var(--text); }
.search-item mark { background: var(--warn-soft); color: var(--warn); border-radius: 3px; padding: 0 2px; }
.search-item .match-in {
  display: inline-block;
  margin: 2px 6px 0 0;
  font-size: 11.5px;
  font-weight: 700;
  color: var(--accent);
  background: color-mix(in srgb, var(--accent) 14%, transparent);
  border-radius: 6px;
  padding: 1px 7px;
  vertical-align: 1px;
}
.search-item .meta { display: flex; gap: 8px; align-items: center; margin-top: 8px; }
.search-empty { text-align: center; color: var(--faint); padding: 46px 0; font-size: 13px; }

/* ============ 弹窗 / Toast ============ */
.modal-mask {
  position: fixed; inset: 0; z-index: 90;
  background: rgba(4, 6, 12, 0.62); backdrop-filter: blur(6px);
  display: flex; align-items: center; justify-content: center; padding: 20px;
  opacity: 0; pointer-events: none; transition: opacity 0.25s ease;
}
.modal-mask.show { opacity: 1; pointer-events: auto; }
.modal {
  width: 100%; max-width: 560px; max-height: 82vh; overflow-y: auto;
  background: var(--card2); border: 1px solid var(--line2);
  border-radius: 20px; padding: 20px;
  transform: translateY(16px) scale(0.98); transition: transform 0.28s cubic-bezier(0.22, 1, 0.36, 1);
  box-shadow: var(--shadow);
}
.modal-mask.show .modal { transform: none; }
.modal .m-head { display: flex; align-items: center; justify-content: space-between; margin-bottom: 14px; }
.modal .m-title { font-size: 16px; font-weight: 800; }

#toast {
  position: fixed; left: 50%; bottom: calc(30px + var(--safe-b));
  transform: translateX(-50%) translateY(20px);
  z-index: 120; padding: 10px 18px; border-radius: 999px;
  background: var(--card3); color: var(--text); font-size: 13px; font-weight: 600;
  border: 1px solid var(--line2); box-shadow: var(--shadow-sm);
  opacity: 0; pointer-events: none; transition: all 0.28s cubic-bezier(0.22, 1, 0.36, 1);
  white-space: nowrap; max-width: 90vw; overflow: hidden; text-overflow: ellipsis;
}
#toast.show { opacity: 1; transform: translateX(-50%) translateY(0); }

/* 无头/窄屏细节 */
@media (min-width: 700px) {
  #app { padding-top: 6px; }
  .hero { padding: 26px 24px; }
  .q-text { font-size: 18px; }
}
@media (max-width: 380px) {
  .mode-grid { grid-template-columns: 1fr; }
  .stat-block { min-width: 60px; }
}

@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after { animation-duration: 0.01ms !important; transition-duration: 0.01ms !important; }
}

/* ============ 移动端优化：顶部留白 + 底部固定操作栏 ============ */
body.no-topbar main { padding-top: calc(18px + env(safe-area-inset-top, 0px)); }

@media (max-width: 640px) {
  /* 上一题/下一题 固定在底部，不再随内容滚走 */
  .nav-row {
    position: fixed; left: 0; right: 0; bottom: 0; z-index: 55;
    margin: 0; padding: 10px 16px calc(10px + var(--safe-b));
    background: var(--card); border-top: 1px solid var(--line2);
  }
  .nav-row .btn { padding: 13px 18px; font-size: 15px; }
  /* 为底部固定栏让出滚动空间 */
  #view-quiz { padding-bottom: calc(86px + var(--safe-b)); }
  /* 题目卡片扁平化：去掉卡片外框与内边距，题目直接平铺 */
  #view-quiz .card { background: transparent; border: none; box-shadow: none; border-radius: 0; }
  #view-quiz .q-card { padding: 0; }
}

/* ============ 图标（Lucide sprite）与内联图标尺寸 ============ */
.ic { display: inline-block; width: 1.15em; height: 1.15em; flex: none; vertical-align: -0.2em; }
.hero-badge svg { width: 12px; height: 12px; vertical-align: -1.5px; }
.txt-ic { display: inline-block; vertical-align: -0.18em; width: 1em; height: 1em; }
.txt-ic svg { width: 100%; height: 100%; }
.q-tip-strip .lb svg { width: 14px; height: 14px; vertical-align: -2px; }
.result-tip svg { width: 14px; height: 14px; vertical-align: -2px; color: var(--warn); }
.result-ana svg { width: 13px; height: 13px; vertical-align: -2px; color: var(--accent); }
.result-head .big svg { width: 24px; height: 24px; }
.result-panel.correct .result-head .big svg { color: var(--ok); }
.result-panel.wrong .result-head .big svg { color: var(--bad); }
.result-head .big { line-height: 1; }
.tips-intro h2 svg { width: 22px; height: 22px; vertical-align: -4px; }
.search-empty .txt-ic { display: block; margin: 0 auto 10px; width: 22px; height: 22px; opacity: 0.55; }
.opt .k svg { width: 16px; height: 16px; }
.opt .mk svg { width: 17px; height: 17px; }
.opt .k.k-true { color: var(--ok); }
.opt .k.k-false { color: var(--bad); }
.btn .ic { width: 16px; height: 16px; }
.icon-btn .ic { width: 18px; height: 18px; }
.chip .ic { width: 15px; height: 15px; }
#boot {
  position: fixed; inset: 0; z-index: 200;
  display: flex; align-items: center; justify-content: center;
  background: var(--bg); padding: 24px;
  transition: opacity 0.25s ease;
}
#boot.done { opacity: 0; pointer-events: none; }
.boot-card {
  max-width: 460px; width: 100%; text-align: center;
  background: var(--card); border: 1px solid var(--line);
  border-radius: 20px; padding: 30px 26px; box-shadow: var(--shadow);
}
.boot-spinner {
  width: 34px; height: 34px; margin: 0 auto 16px;
  border-radius: 50%;
  border: 3px solid var(--card3);
  border-top-color: var(--accent);
  animation: spin 0.9s linear infinite;
}
@keyframes spin { to { transform: rotate(360deg); } }
.boot-ico { font-size: 34px; margin-bottom: 10px; }
.boot-msg { font-size: 15px; font-weight: 700; color: var(--text); }
.boot-sub { font-size: 12.5px; color: var(--muted); line-height: 1.8; margin-top: 12px; text-align: left; }
.boot-list { text-align: left; margin: 10px 0 16px 18px; font-size: 12.5px; color: var(--muted); line-height: 2; }
.boot-list code {
  font-family: var(--mono); font-size: 11.5px; color: var(--accent);
  background: var(--accent-soft); border-radius: 5px; padding: 1px 6px;
}