/* ============================================================
   AI防痨，健康同行 · 结核病防治知识闯关
   配色沿用科普作品的青绿 / 珊瑚，暗底为了让「光盾」亮起来
   ============================================================ */

:root {
  --top-h: 92px;
  --bottom-h: 58px;

  --bg-0: #061318;
  --bg-1: #0a2028;
  --ink: #eaf7f6;
  --ink-dim: #9fb8bd;
  --teal: #19c2b0;
  --teal-lt: #5ff0dd;
  --coral: #ff6b4a;
  --gold: #ffd166;
  --purple: #a259d0;
  --danger: #ff4d6d;
  --ok: #35d39a;

  --card: rgba(255, 255, 255, 0.055);
  --card-line: rgba(150, 235, 225, 0.18);

  --radius: 18px;
  --font: "PingFang SC", "HarmonyOS Sans SC", "Microsoft YaHei", "Noto Sans SC",
    system-ui, -apple-system, "Segoe UI", sans-serif;
}

* { box-sizing: border-box; }

/* 关键：任何带 hidden 的元素都必须消失，否则 .board__feedback 的 display:grid 会盖掉它 */
[hidden] { display: none !important; }

html, body {
  height: 100%;
  margin: 0;
}

body {
  font-family: var(--font);
  color: var(--ink);
  background:
    radial-gradient(1100px 620px at 12% 8%, rgba(25, 194, 176, 0.20), transparent 62%),
    radial-gradient(900px 560px at 88% 18%, rgba(162, 89, 208, 0.22), transparent 60%),
    radial-gradient(700px 500px at 50% 108%, rgba(255, 107, 74, 0.14), transparent 65%),
    linear-gradient(175deg, var(--bg-1), var(--bg-0) 62%);
  overflow: hidden;
  -webkit-font-smoothing: antialiased;
}

/* 细网格底纹 */
body::before {
  content: "";
  position: fixed;
  inset: 0;
  background-image:
    linear-gradient(rgba(120, 220, 210, 0.055) 1px, transparent 1px),
    linear-gradient(90deg, rgba(120, 220, 210, 0.055) 1px, transparent 1px);
  background-size: 46px 46px;
  mask-image: radial-gradient(circle at 50% 42%, #000 30%, transparent 78%);
  pointer-events: none;
  z-index: 0;
}

/* ------------------------------------------------------------ 顶部 / 底部 */

.topbar {
  position: fixed;
  inset: 0 0 auto 0;
  height: var(--top-h);
  z-index: 40;
  background: linear-gradient(180deg, rgba(5, 18, 22, 0.96), rgba(5, 18, 22, 0.72));
  backdrop-filter: blur(10px);
  -webkit-backdrop-filter: blur(10px);
}

.topbar__inner {
  height: 100%;
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 18px;
  padding: 0 20px;
  position: relative;
}

.topbar__title {
  margin: 0;
  font-size: clamp(24px, 3.6vw, 44px);
  font-weight: 900;
  letter-spacing: 0.06em;
  line-height: 1;
  background: linear-gradient(96deg, #7dfff0 0%, #ffffff 38%, #ffd166 72%, #ff8a6b 100%);
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
  filter: drop-shadow(0 0 18px rgba(95, 240, 221, 0.45));
  white-space: nowrap;
}

.topbar__tools {
  position: absolute;
  right: 16px;
  top: 50%;
  transform: translateY(-50%);
  display: flex;
  gap: 8px;
}

.topbar__line {
  position: absolute;
  left: 0; right: 0; bottom: 0;
  height: 2px;
  background: linear-gradient(90deg, transparent, var(--teal), var(--gold), var(--coral), transparent);
  opacity: 0.75;
}

.tool {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 7px 12px;
  font: inherit;
  font-size: 13px;
  color: var(--ink-dim);
  background: rgba(255, 255, 255, 0.06);
  border: 1px solid var(--card-line);
  border-radius: 999px;
  cursor: pointer;
  transition: color 0.18s, background 0.18s, border-color 0.18s;
}

.tool:hover { color: var(--ink); border-color: rgba(95, 240, 221, 0.5); }
.tool[aria-pressed="false"] { opacity: 0.55; }
.tool__text { display: none; }

@media (min-width: 720px) { .tool__text { display: inline; } }

.bottombar {
  position: fixed;
  inset: auto 0 0 0;
  height: var(--bottom-h);
  z-index: 40;
  display: flex;
  align-items: center;
  justify-content: center;
  background: linear-gradient(0deg, rgba(5, 18, 22, 0.96), rgba(5, 18, 22, 0.6));
  backdrop-filter: blur(10px);
  -webkit-backdrop-filter: blur(10px);
  border-top: 1px solid rgba(150, 235, 225, 0.14);
}

.bottombar__school {
  font-size: 17px;
  font-weight: 800;
  letter-spacing: 0.42em;
  text-indent: 0.42em;
  color: rgba(234, 247, 246, 0.72);
  text-shadow: 0 0 16px rgba(95, 240, 221, 0.28);
}

/* ---------------------------------------------------------------- 战场 */

.arena {
  position: fixed;
  inset: var(--top-h) 0 var(--bottom-h) 0;
  z-index: 10;
  display: grid;
  grid-template-columns: minmax(190px, 0.9fr) minmax(380px, 1.5fr) minmax(190px, 0.9fr);
  grid-template-areas: "girl board demon";
  gap: clamp(10px, 1.6vw, 26px);
  padding: clamp(12px, 1.8vh, 26px) clamp(14px, 2vw, 34px);
  align-items: center;
  overflow: auto;
}

.fighter {
  grid-area: auto;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 12px;
  min-width: 0;
}

.fighter--girl { grid-area: girl; }
.fighter--demon { grid-area: demon; }

.fighter__figure {
  width: 100%;
  display: flex;
  justify-content: center;
}

.hero {
  width: auto;
  height: clamp(200px, 44vh, 400px);
  max-width: 100%;
  overflow: visible;
}

.hero--demon { animation: floaty 4.4s ease-in-out infinite; }
.hero--girl { animation: floaty 5.2s ease-in-out infinite reverse; }

@keyframes floaty {
  0%, 100% { transform: translateY(0); }
  50% { transform: translateY(-12px); }
}

.hero__ring { animation: spin 26s linear infinite; transform-origin: 110px 155px; }
.hero__aura { animation: breathe 3.6s ease-in-out infinite; transform-origin: 110px 155px; }
.demon__aura { animation: breathe 3.1s ease-in-out infinite; transform-origin: 110px 160px; }
.hero__orb { animation: pulseOrb 2.2s ease-in-out infinite; }

@keyframes spin { to { transform: rotate(360deg); } }
@keyframes breathe { 0%, 100% { opacity: 0.75; transform: scale(1); } 50% { opacity: 1; transform: scale(1.05); } }
@keyframes pulseOrb { 0%, 100% { opacity: 0.85; } 50% { opacity: 1; } }

.fighter__meta {
  width: min(240px, 100%);
  text-align: center;
}

.fighter__name {
  margin: 0 0 6px;
  font-size: 14px;
  font-weight: 700;
  letter-spacing: 0.05em;
  color: var(--ink-dim);
}

.meter {
  height: 12px;
  border-radius: 999px;
  background: rgba(255, 255, 255, 0.1);
  border: 1px solid rgba(255, 255, 255, 0.12);
  overflow: hidden;
}

.meter__fill {
  height: 100%;
  width: 100%;
  border-radius: 999px;
  transition: width 0.55s cubic-bezier(0.22, 1, 0.36, 1);
}

.meter--hp .meter__fill {
  background: linear-gradient(90deg, #ff8a5b, var(--danger) 60%, #b3244a);
  box-shadow: 0 0 12px rgba(255, 77, 109, 0.6);
}

.meter--shield .meter__fill {
  background: linear-gradient(90deg, var(--teal), var(--teal-lt));
  box-shadow: 0 0 12px rgba(95, 240, 221, 0.6);
}

.meter__label {
  margin: 6px 0 0;
  font-size: 12.5px;
  color: var(--ink-dim);
  letter-spacing: 0.04em;
}

.meter__label b { color: var(--ink); font-weight: 800; }

/* ---------------------------------------------------------------- 答题板 */

.board {
  grid-area: board;
  width: 100%;
  max-width: 720px;
  margin: 0 auto;
  padding: clamp(16px, 2.2vh, 26px) clamp(16px, 2vw, 28px);
  background: linear-gradient(180deg, rgba(255, 255, 255, 0.085), rgba(255, 255, 255, 0.03));
  border: 1px solid var(--card-line);
  border-radius: var(--radius);
  box-shadow: 0 24px 60px rgba(0, 0, 0, 0.42), inset 0 1px 0 rgba(255, 255, 255, 0.12);
  backdrop-filter: blur(8px);
  -webkit-backdrop-filter: blur(8px);
  display: flex;
  flex-direction: column;
  gap: 14px;
}

.board__hud {
  display: flex;
  gap: 8px;
  flex-wrap: wrap;
}

.chip {
  font-size: 12.5px;
  padding: 5px 11px;
  border-radius: 999px;
  border: 1px solid var(--card-line);
  color: var(--ink-dim);
  background: rgba(255, 255, 255, 0.04);
}

.chip b { color: var(--ink); font-weight: 800; }
.chip--q { border-color: rgba(95, 240, 221, 0.32); }
.chip--hit { border-color: rgba(255, 209, 102, 0.32); }
.chip--hit b { color: var(--gold); }

.board__tag {
  margin: 0;
  font-size: 12.5px;
  letter-spacing: 0.12em;
  color: var(--teal-lt);
  opacity: 0.9;
}

.board__question {
  margin: 0;
  font-size: clamp(18px, 1.9vw, 25px);
  line-height: 1.55;
  font-weight: 800;
  letter-spacing: 0.01em;
  min-height: 2.2em;
}

.board__options {
  display: grid;
  gap: 10px;
}

.opt {
  display: flex;
  align-items: center;
  gap: 12px;
  width: 100%;
  padding: 13px 15px;
  font: inherit;
  font-size: clamp(14px, 1.15vw, 16px);
  line-height: 1.5;
  text-align: left;
  color: var(--ink);
  background: rgba(255, 255, 255, 0.05);
  border: 1px solid rgba(255, 255, 255, 0.13);
  border-radius: 13px;
  cursor: pointer;
  transition: transform 0.14s, border-color 0.16s, background 0.16s, box-shadow 0.16s;
}

.opt:hover:not(:disabled) {
  transform: translateX(4px);
  border-color: rgba(95, 240, 221, 0.6);
  background: rgba(95, 240, 221, 0.1);
  box-shadow: 0 0 0 3px rgba(95, 240, 221, 0.08);
}

.opt:disabled { cursor: default; }

.opt__key {
  flex: none;
  width: 26px;
  height: 26px;
  display: grid;
  place-items: center;
  font-size: 13px;
  font-weight: 800;
  color: var(--teal-lt);
  background: rgba(95, 240, 221, 0.12);
  border: 1px solid rgba(95, 240, 221, 0.32);
  border-radius: 8px;
}

.opt.is-correct {
  background: rgba(53, 211, 154, 0.18);
  border-color: var(--ok);
  box-shadow: 0 0 0 3px rgba(53, 211, 154, 0.15);
}

.opt.is-correct .opt__key { color: #04211a; background: var(--ok); border-color: var(--ok); }

.opt.is-wrong {
  background: rgba(255, 77, 109, 0.18);
  border-color: var(--danger);
  animation: wobble 0.4s;
}

.opt.is-wrong .opt__key { color: #2b0410; background: var(--danger); border-color: var(--danger); }

.opt.is-dim { opacity: 0.45; }

@keyframes wobble {
  0%, 100% { transform: translateX(0); }
  25% { transform: translateX(-7px); }
  55% { transform: translateX(6px); }
  80% { transform: translateX(-3px); }
}

.board__feedback {
  display: grid;
  gap: 8px;
  padding: 13px 15px;
  border-radius: 13px;
  background: rgba(95, 240, 221, 0.07);
  border: 1px solid rgba(95, 240, 221, 0.22);
  animation: fadeUp 0.28s ease-out;
}

.board__feedback.is-bad {
  background: rgba(255, 77, 109, 0.09);
  border-color: rgba(255, 77, 109, 0.3);
}

.feedback__verdict {
  margin: 0;
  font-size: 15px;
  font-weight: 800;
  letter-spacing: 0.03em;
}

.feedback__tip {
  margin: 0;
  font-size: 13.5px;
  line-height: 1.7;
  color: #cfe6e4;
}

.board__feedback .btn { justify-self: end; margin-top: 2px; }

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

/* ---------------------------------------------------------------- 按钮 */

.btn {
  font: inherit;
  font-size: 15px;
  font-weight: 700;
  letter-spacing: 0.03em;
  padding: 11px 22px;
  border-radius: 999px;
  border: 1px solid transparent;
  cursor: pointer;
  transition: transform 0.14s, box-shadow 0.18s, background 0.18s, border-color 0.18s;
}

.btn--primary {
  color: #04211f;
  background: linear-gradient(135deg, var(--teal-lt), var(--teal) 55%, #0e9c8e);
  box-shadow: 0 10px 26px rgba(25, 194, 176, 0.35);
}

.btn--primary:hover { transform: translateY(-2px); box-shadow: 0 14px 32px rgba(25, 194, 176, 0.45); }
.btn--primary:active { transform: translateY(0); }

.btn--ghost {
  color: var(--ink);
  background: rgba(255, 255, 255, 0.06);
  border-color: var(--card-line);
}

.btn--ghost:hover { border-color: rgba(95, 240, 221, 0.55); background: rgba(95, 240, 221, 0.1); }

.btn--lg { padding: 14px 40px; font-size: 17px; }

.btn:focus-visible { outline: 3px solid rgba(255, 209, 102, 0.85); outline-offset: 3px; }

/* ---------------------------------------------------------------- 特效 */

.fx {
  position: fixed;
  inset: 0;
  pointer-events: none;
  z-index: 30;
}

.beam {
  position: fixed;
  height: 16px;
  border-radius: 999px;
  background: linear-gradient(90deg, rgba(255, 255, 255, 0), #ccfff7 18%, #ffffff 50%, #5ff0dd 82%, rgba(95, 240, 221, 0));
  box-shadow: 0 0 26px rgba(95, 240, 221, 0.9), 0 0 60px rgba(95, 240, 221, 0.5);
  transform-origin: 0 50%;
  animation: beamFire 0.55s cubic-bezier(0.2, 0.8, 0.3, 1) forwards;
}

@keyframes beamFire {
  0% { opacity: 0; transform: rotate(var(--rot)) scaleX(0.02); }
  18% { opacity: 1; }
  55% { opacity: 1; }
  100% { opacity: 0; transform: rotate(var(--rot)) scaleX(1); }
}

.ring {
  position: fixed;
  width: 60px;
  height: 60px;
  margin: -30px 0 0 -30px;
  border-radius: 50%;
  border: 3px solid var(--teal-lt);
  box-shadow: 0 0 24px rgba(95, 240, 221, 0.8), inset 0 0 18px rgba(95, 240, 221, 0.5);
  animation: ringOut 0.62s ease-out forwards;
}

@keyframes ringOut {
  0% { opacity: 0.95; transform: scale(0.25); }
  100% { opacity: 0; transform: scale(3.4); }
}

.ring--bad { border-color: var(--danger); box-shadow: 0 0 24px rgba(255, 77, 109, 0.8), inset 0 0 18px rgba(255, 77, 109, 0.5); }

.dmg {
  position: fixed;
  font-size: 30px;
  font-weight: 900;
  letter-spacing: 0.02em;
  color: #fff;
  text-shadow: 0 0 14px currentColor, 0 3px 0 rgba(0, 0, 0, 0.35);
  animation: dmgFloat 0.95s cubic-bezier(0.2, 0.9, 0.3, 1) forwards;
}

.dmg--hit { color: #7dffe4; }
.dmg--heal { color: #ff7d9c; }

@keyframes dmgFloat {
  0% { opacity: 0; transform: translate(-50%, 0) scale(0.6); }
  25% { opacity: 1; transform: translate(-50%, -18px) scale(1.15); }
  100% { opacity: 0; transform: translate(-50%, -78px) scale(1); }
}

.flash {
  position: fixed;
  inset: 0;
  background: radial-gradient(circle at 50% 45%, rgba(255, 255, 255, 0.35), transparent 60%);
  animation: flashOut 0.4s ease-out forwards;
}

@keyframes flashOut { from { opacity: 0.9; } to { opacity: 0; } }

.arena.is-shaking { animation: shake 0.42s cubic-bezier(0.36, 0.07, 0.19, 0.97); }

@keyframes shake {
  10%, 90% { transform: translate3d(-3px, 0, 0); }
  20%, 80% { transform: translate3d(6px, 0, 0); }
  30%, 50%, 70% { transform: translate3d(-10px, 0, 0); }
  40%, 60% { transform: translate3d(10px, 0, 0); }
}

.hero--demon.is-hit { animation: demonHit 0.5s ease-out; }

@keyframes demonHit {
  0% { transform: translateX(0) rotate(0); filter: brightness(1); }
  15% { transform: translateX(14px) rotate(5deg); filter: brightness(2.2) hue-rotate(-25deg); }
  35% { transform: translateX(-16px) rotate(-5deg); filter: brightness(1.5); }
  55% { transform: translateX(11px) rotate(3deg); }
  75% { transform: translateX(-7px) rotate(-2deg); }
  100% { transform: translateX(0) rotate(0); filter: brightness(1); }
}

.hero--demon.is-heal { animation: demonHeal 0.7s ease-out; }

@keyframes demonHeal {
  0% { transform: scale(1); filter: brightness(1); }
  30% { transform: scale(1.09); filter: brightness(1.5) hue-rotate(70deg) saturate(1.4); }
  60% { transform: scale(0.97); }
  100% { transform: scale(1); filter: brightness(1); }
}

.hero--girl.is-guard { animation: girlGuard 0.6s ease-out; }

@keyframes girlGuard {
  0% { transform: scale(1); }
  30% { transform: scale(0.94) rotate(-3deg); }
  100% { transform: scale(1); }
}

/* ---------------------------------------------------------------- 弹层 */

.overlay {
  position: fixed;
  inset: 0;
  z-index: 50;
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 20px;
  background: rgba(3, 12, 16, 0.74);
  backdrop-filter: blur(8px);
  -webkit-backdrop-filter: blur(8px);
  animation: fadeIn 0.24s ease-out;
}

.overlay[hidden] { display: none !important; }

/* 结算、排行榜要压在开始页之上 */
#resultOverlay { z-index: 52; }
#rankOverlay { z-index: 54; }

@keyframes fadeIn { from { opacity: 0; } to { opacity: 1; } }

.panel {
  width: min(560px, 100%);
  max-height: calc(100vh - 40px);
  overflow: auto;
  padding: clamp(22px, 3vw, 34px);
  text-align: center;
  background: linear-gradient(180deg, rgba(18, 46, 54, 0.96), rgba(8, 24, 30, 0.98));
  border: 1px solid rgba(95, 240, 221, 0.24);
  border-radius: 22px;
  box-shadow: 0 40px 90px rgba(0, 0, 0, 0.6), inset 0 1px 0 rgba(255, 255, 255, 0.1);
  animation: popIn 0.3s cubic-bezier(0.2, 0.9, 0.3, 1);
}

@keyframes popIn {
  from { opacity: 0; transform: translateY(16px) scale(0.97); }
  to { opacity: 1; transform: none; }
}

.panel__kicker {
  margin: 0 0 6px;
  font-size: 12.5px;
  letter-spacing: 0.3em;
  text-indent: 0.3em;
  color: var(--teal-lt);
}

.panel__title {
  margin: 0 0 12px;
  font-size: clamp(28px, 4.4vw, 42px);
  font-weight: 900;
  letter-spacing: 0.08em;
  background: linear-gradient(96deg, #7dfff0, #ffffff 45%, #ffd166 100%);
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
  filter: drop-shadow(0 0 20px rgba(95, 240, 221, 0.35));
}

.panel__desc {
  margin: 0 0 18px;
  font-size: 14.5px;
  line-height: 1.85;
  color: #c6dedc;
}

.rules {
  list-style: none;
  margin: 0 0 20px;
  padding: 14px 16px;
  text-align: left;
  background: rgba(255, 255, 255, 0.04);
  border: 1px solid var(--card-line);
  border-radius: 14px;
  display: grid;
  gap: 9px;
  font-size: 14px;
  color: #d3e9e7;
}

.rules b { color: var(--gold); }

.field {
  display: grid;
  gap: 7px;
  margin-bottom: 20px;
  text-align: left;
  font-size: 13px;
  color: var(--ink-dim);
}

.field input {
  font: inherit;
  font-size: 15px;
  padding: 12px 15px;
  color: var(--ink);
  background: rgba(255, 255, 255, 0.06);
  border: 1px solid var(--card-line);
  border-radius: 12px;
}

.field input:focus {
  outline: none;
  border-color: rgba(95, 240, 221, 0.6);
  box-shadow: 0 0 0 3px rgba(95, 240, 221, 0.12);
}

.panel--start .btn,
.panel--result .btn { margin-top: 10px; }

.panel__actions {
  display: flex;
  gap: 10px;
  justify-content: center;
  flex-wrap: wrap;
  margin-top: 6px;
}

.medal {
  width: 92px;
  height: 92px;
  margin: 0 auto 8px;
  filter: drop-shadow(0 0 26px rgba(25, 194, 176, 0.55));
  animation: medalPop 0.7s cubic-bezier(0.2, 1.2, 0.3, 1);
}

.medal svg { width: 100%; height: 100%; }

@keyframes medalPop {
  0% { transform: scale(0.4) rotate(-18deg); opacity: 0; }
  60% { transform: scale(1.12) rotate(4deg); opacity: 1; }
  100% { transform: scale(1) rotate(0); }
}

.stats {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(96px, 1fr));
  gap: 10px;
  margin: 4px 0 14px;
}

.stat {
  padding: 12px 8px;
  border-radius: 13px;
  background: rgba(255, 255, 255, 0.05);
  border: 1px solid var(--card-line);
}

.stat__num {
  display: block;
  font-size: 24px;
  font-weight: 900;
  color: var(--teal-lt);
  line-height: 1.2;
}

.stat__label { font-size: 12px; color: var(--ink-dim); }

.result__note {
  margin: 6px 0 4px;
  font-size: 12.5px;
  line-height: 1.7;
  color: var(--ink-dim);
  min-height: 1.2em;
}

.ranklist {
  list-style: none;
  margin: 0 0 14px;
  padding: 0;
  display: grid;
  gap: 8px;
  text-align: left;
}

.ranklist li {
  display: flex;
  align-items: center;
  gap: 12px;
  padding: 11px 14px;
  border-radius: 12px;
  background: rgba(255, 255, 255, 0.045);
  border: 1px solid var(--card-line);
  font-size: 14px;
}

.ranklist li.is-top {
  background: linear-gradient(90deg, rgba(255, 209, 102, 0.16), rgba(255, 209, 102, 0.03));
  border-color: rgba(255, 209, 102, 0.4);
}

.rank__no {
  flex: none;
  width: 26px;
  height: 26px;
  display: grid;
  place-items: center;
  border-radius: 8px;
  font-size: 12.5px;
  font-weight: 800;
  color: var(--gold);
  background: rgba(255, 209, 102, 0.14);
}

.rank__name {
  flex: 1;
  min-width: 0;
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
}

.rank__meta { font-size: 12px; color: var(--ink-dim); white-space: nowrap; }
.rank__score { font-weight: 900; color: var(--teal-lt); white-space: nowrap; }

.ranklist__empty {
  padding: 22px 0;
  text-align: center;
  color: var(--ink-dim);
  font-size: 13.5px;
}

/* ---------------------------------------------------------------- 响应式 */

@media (max-width: 1000px) {
  :root { --top-h: 78px; --bottom-h: 52px; }

  .arena {
    grid-template-columns: 1fr 1fr;
    grid-template-areas:
      "girl demon"
      "board board";
    align-content: start;
    gap: 8px 12px;
    padding: 10px 12px 14px;
  }

  .hero { height: clamp(130px, 22vh, 220px); }

  .fighter__meta { width: min(200px, 100%); }
  .fighter__name { font-size: 12.5px; margin-bottom: 4px; }
  .meter { height: 9px; }
  .meter__label { font-size: 11.5px; margin-top: 4px; }

  .board { max-width: 640px; }
  .bottombar__school { font-size: 15px; }
}

@media (max-width: 560px) {
  .topbar__title { letter-spacing: 0.02em; }
  .board__question { font-size: 17px; }
  .opt { padding: 11px 12px; font-size: 13.5px; gap: 9px; }
  .opt__key { width: 22px; height: 22px; font-size: 12px; }
  .panel { padding: 20px 18px; }
}

/* 超窄屏：标题会让位给按钮，全屏按钮在手机上意义不大 */
@media (max-width: 440px) {
  :root { --top-h: 70px; }
  .topbar__title { font-size: 20px; }
  .topbar__tools { right: 8px; gap: 6px; }
  .tool { padding: 6px 9px; }
  #btnFullscreen { display: none; }
  .bottombar__school { font-size: 14px; letter-spacing: 0.3em; text-indent: 0.3em; }
}

/* 矮屏（笔记本 720p 之类）压缩一点 */
@media (max-height: 760px) and (min-width: 1000px) {
  .hero { height: clamp(170px, 36vh, 300px); }
  .board { gap: 10px; }
  .board__question { font-size: clamp(17px, 1.7vw, 21px); }
}

@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after {
    animation-duration: 0.001ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.001ms !important;
  }
}