:root {
  --ink: #1b3140;
  --ink-soft: #3e5666;
  --line: #c9ddd9;
  --card: #ffffff;
  --teal: #0f6e78;
  --teal-dark: #0a5158;
  --teal-soft: #e5f5f3;
  --sand: #fff8ee;
  --sand-line: #f0d7b0;
  --sand-ink: #6a4b16;
  --sky: #e7f2f8;
  --bg: #f3f7f5;
  --shadow: 0 10px 28px rgba(27, 49, 64, 0.08);
  --radius: 18px;
  --tap: 3.5rem;
  font-size: 18px;
}

*,
*::before,
*::after {
  box-sizing: border-box;
}

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

body {
  color: var(--ink);
  background:
    radial-gradient(circle at 0% -8%, #d9f3ee 0, transparent 38%),
    radial-gradient(circle at 100% 0%, #fde8c8 0, transparent 32%),
    var(--bg);
  font-family: "PingFang HK", "PingFang TC", "Noto Sans CJK TC", "Noto Sans TC", "Source Han Sans TC", "Microsoft JhengHei", "Heiti TC", sans-serif;
  line-height: 1.55;
}

button,
input,
label {
  font: inherit;
  color: inherit;
  touch-action: manipulation;
}

button {
  cursor: pointer;
  -webkit-tap-highlight-color: rgba(15, 110, 120, 0.18);
}

button,
.choice,
.ab-card {
  user-select: none;
}

img,
svg {
  max-width: 100%;
  display: block;
}

h1,
h2,
h3,
p {
  margin: 0;
}

.skip {
  position: absolute;
  left: 0.75rem;
  top: -4rem;
  background: var(--teal);
  color: #fff;
  padding: 0.5rem 0.8rem;
  border-radius: 8px;
  z-index: 5;
}

.skip:focus {
  top: 0.75rem;
}

.sr {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  border: 0;
}

.noscript {
  width: min(40rem, calc(100% - 1.5rem));
  margin: 1rem auto;
  padding: 1rem;
  background: var(--sand);
  border-radius: 12px;
}

.shell {
  width: min(1080px, calc(100% - 1.25rem));
  margin: 0 auto;
  padding: 0.85rem 0 2.5rem;
}

.top {
  display: flex;
  flex-wrap: wrap;
  align-items: flex-start;
  justify-content: space-between;
  gap: 0.75rem 1rem;
  margin-bottom: 1rem;
}

.top.bare {
  padding-top: 1.25rem;
}

.kicker {
  color: var(--teal-dark);
  font-weight: 700;
  letter-spacing: 0.02em;
  font-size: 0.95rem;
}

h1 {
  font-size: clamp(1.7rem, 3vw, 2.35rem);
  line-height: 1.25;
  margin: 0.15rem 0 0.25rem;
}

.lede {
  color: var(--ink-soft);
  font-size: 1.05rem;
  max-width: 40rem;
}

.top-actions,
.nav-row,
.record-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 0.6rem;
  align-items: center;
}

.btn {
  min-height: var(--tap);
  padding: 0.7rem 1.15rem;
  border-radius: 999px;
  border: 3px solid var(--teal);
  background: #fff;
  color: var(--teal-dark);
  font-weight: 700;
  line-height: 1.3;
}

.btn:hover,
.btn:focus-visible {
  background: var(--teal-soft);
  outline: none;
}

.btn:focus-visible,
.choice:focus-within,
.group-btn:focus-visible,
.step:focus-visible,
.ab-card:focus-within {
  outline: 3px solid #e0903a;
  outline-offset: 2px;
}

.btn-primary {
  background: var(--teal);
  color: #fff;
}

.btn-primary:hover,
.btn-primary:focus-visible {
  background: var(--teal-dark);
  color: #fff;
}

.btn:disabled,
.btn[aria-disabled="true"] {
  background: #d5e1e2;
  border-color: #d5e1e2;
  color: #31464e;
  cursor: not-allowed;
}

.panel {
  background: var(--card);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  padding: 1rem 1rem 1.1rem;
  margin-bottom: 0.9rem;
}

.panel h2 {
  font-size: clamp(1.35rem, 2.4vw, 1.8rem);
  line-height: 1.3;
  margin-bottom: 0.35rem;
}

.sub {
  color: var(--ink-soft);
  margin-bottom: 0.75rem;
}

.note {
  background: var(--teal-soft);
  border-radius: 14px;
  padding: 0.75rem 0.9rem;
  margin: 0.75rem 0;
}

.note.warn {
  background: var(--sand);
  color: var(--sand-ink);
}

.banner {
  background: #e7f3f8;
  border: 3px solid #b7d4e4;
  border-radius: 16px;
  padding: 0.9rem 1rem;
  font-weight: 700;
  margin-bottom: 0.9rem;
}

.banner:focus {
  outline: 3px solid #e0903a;
}

.group-box h2,
.section-title {
  font-size: 1.15rem;
  margin-bottom: 0.35rem;
}

.hint {
  color: var(--ink-soft);
  font-size: 0.95rem;
  margin-bottom: 0.7rem;
}

.group-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(3.15rem, 1fr));
  gap: 0.5rem;
  max-width: 28rem;
}

.group-box.compact {
  margin-bottom: 0.9rem;
}

.group-box.compact h2 {
  font-size: 1.05rem;
}

.group-btn {
  min-height: 3.15rem;
  border-radius: 14px;
  border: 3px solid var(--line);
  background: #fff;
  font-weight: 800;
  font-size: 1.15rem;
}

.group-btn[aria-pressed="true"] {
  background: var(--teal);
  border-color: var(--teal);
  color: #fff;
}

.cards {
  display: grid;
  gap: 0.9rem;
}

a.activity-card {
  text-decoration: none;
  color: inherit;
}

.activity-card {
  text-align: left;
  width: 100%;
  background: #fff;
  border: 3px solid transparent;
  border-radius: 22px;
  box-shadow: var(--shadow);
  padding: 1rem;
  display: grid;
  grid-template-columns: auto 1fr;
  gap: 0.85rem 1rem;
  align-items: center;
}

.activity-card.cup {
  border-color: #b7ddd8;
}

.activity-card.box {
  border-color: #f0d3a4;
}

.activity-card:hover,
.activity-card:focus-visible {
  border-color: var(--teal);
  outline: none;
}

.icon-wrap {
  width: 4.6rem;
  height: 4.6rem;
  border-radius: 18px;
  display: grid;
  place-items: center;
  background: var(--teal-soft);
}

.activity-card.box .icon-wrap {
  background: #fff3e2;
}

.icon-wrap svg {
  width: 3.2rem;
  height: 3.2rem;
}

.card-kicker {
  color: var(--teal-dark);
  font-weight: 800;
  font-size: 0.92rem;
}

.activity-card h2 {
  font-size: 1.45rem;
  line-height: 1.25;
}

.card-q {
  font-size: 1.12rem;
  margin: 0.15rem 0 0.35rem;
}

.meta {
  color: var(--ink-soft);
  font-size: 0.95rem;
}

.status-pill {
  display: inline-block;
  margin-top: 0.45rem;
  background: var(--sky);
  border-radius: 999px;
  padding: 0.2rem 0.7rem;
  font-weight: 700;
  font-size: 0.92rem;
}

.stepper {
  display: grid;
  grid-template-columns: repeat(4, minmax(0, 1fr));
  gap: 0.45rem;
  margin-bottom: 0.85rem;
}

.step {
  min-height: 3.4rem;
  border-radius: 14px;
  border: 3px solid var(--line);
  background: #fff;
  padding: 0.35rem 0.4rem;
  line-height: 1.25;
  font-weight: 700;
}

.step small {
  display: block;
  font-weight: 700;
  font-size: 0.78rem;
  color: var(--ink-soft);
}

.step[aria-current="step"] {
  background: var(--teal);
  border-color: var(--teal);
  color: #fff;
}

.step[aria-current="step"] small {
  color: #e5f7f6;
}

.how {
  display: grid;
  gap: 0.45rem;
  margin: 0.4rem 0 0.2rem;
  padding: 0;
  list-style: none;
}

.how li {
  background: var(--sky);
  border-radius: 12px;
  padding: 0.55rem 0.75rem;
  font-weight: 700;
}

fieldset {
  border: 0;
  margin: 0 0 1rem;
  padding: 0;
  min-inline-size: 0;
}

legend {
  font-weight: 800;
  font-size: 1.12rem;
  padding: 0;
  margin-bottom: 0.55rem;
}

.choices {
  display: grid;
  gap: 0.55rem;
}

.choice {
  display: grid;
  grid-template-columns: 1.35rem 1fr;
  gap: 0.75rem;
  align-items: center;
  min-height: var(--tap);
  padding: 0.75rem 0.9rem;
  border: 3px solid var(--line);
  border-radius: 16px;
  background: #fff;
  cursor: pointer;
}

.choice input {
  width: 1.35rem;
  height: 1.35rem;
  accent-color: var(--teal-dark);
}

.choice:has(input:checked) {
  border-color: var(--teal);
  background: var(--teal-soft);
  box-shadow: inset 5px 0 0 var(--teal);
}

fieldset:disabled .choice {
  cursor: not-allowed;
  background: #f3faf9;
}

.speech {
  display: grid;
  grid-template-columns: auto 1fr;
  gap: 0.75rem;
  align-items: start;
  background: #fff8ee;
  border: 3px solid #f0d7b0;
  border-radius: 18px;
  padding: 0.9rem;
  margin-bottom: 0.9rem;
}

.avatar {
  width: 3.2rem;
  height: 3.2rem;
  border-radius: 50%;
  background: var(--teal);
  color: #fff;
  display: grid;
  place-items: center;
  font-weight: 800;
  font-size: 0.95rem;
}

.speech p {
  font-size: 1.12rem;
}

.obs-group {
  border: 3px solid var(--line);
  border-radius: 16px;
  padding: 0.75rem;
  margin-bottom: 0.65rem;
  background: #fcfffe;
}

.obs-group h3 {
  font-size: 1rem;
  color: var(--ink-soft);
  margin-bottom: 0.5rem;
}

.explain-grid {
  display: grid;
  gap: 0.7rem;
  margin-bottom: 0.9rem;
}

.ab-card {
  display: flex;
  gap: 0.8rem;
  align-items: flex-start;
  min-height: 7.5rem;
  padding: 0.95rem;
  border-radius: 18px;
  border: 3px solid var(--line);
  background: #fff;
  cursor: pointer;
}

.ab-card input {
  margin-top: 0.45rem;
  width: 1.35rem;
  height: 1.35rem;
  flex: 0 0 auto;
  accent-color: var(--teal-dark);
}

.ab-copy {
  display: grid;
  gap: 0.35rem;
}

.ab-kicker {
  display: flex;
  align-items: center;
  gap: 0.55rem;
  font-weight: 800;
  font-size: 1.15rem;
}

.badge {
  width: 2.3rem;
  height: 2.3rem;
  border-radius: 50%;
  display: grid;
  place-items: center;
  background: var(--sky);
  color: var(--ink);
  font-weight: 800;
}

.ab-body {
  font-size: 1.08rem;
}

.ab-card:has(input:checked) {
  border-color: var(--teal);
  background: var(--teal-soft);
}

.choice-both {
  min-height: 4.2rem;
  font-size: 1.12rem;
  font-weight: 800;
}

.ready {
  list-style: none;
  padding: 0;
  margin: 0.3rem 0 0.8rem;
  display: grid;
  gap: 0.35rem;
}

.ready li {
  padding: 0.35rem 0.7rem;
  border-radius: 999px;
  background: #eef2f3;
  font-weight: 700;
}

.ready li.done {
  background: var(--teal-soft);
}

.sentence-preview {
  background: #fff;
  border: 3px dashed var(--teal);
  border-radius: 16px;
  padding: 0.9rem 1rem;
  font-size: 1.15rem;
  font-weight: 700;
  margin: 0.4rem 0 0.8rem;
}

.safety {
  background: var(--sand);
  color: var(--sand-ink);
  border: 2px solid var(--sand-line);
  border-radius: 14px;
  padding: 0.75rem 0.9rem;
  margin-top: 0.4rem;
  font-weight: 700;
}

.foot-links {
  display: flex;
  flex-wrap: wrap;
  gap: 0.6rem;
  margin-top: 0.8rem;
}

pre.record {
  white-space: pre-wrap;
  word-break: break-word;
  background: #f7fbfb;
  border-radius: 14px;
  padding: 0.9rem;
  border: 2px solid var(--line);
  font-family: "PingFang HK", "PingFang TC", "Noto Sans CJK TC", "Microsoft JhengHei", monospace;
  font-size: 1rem;
  line-height: 1.6;
  user-select: text;
}

.two-col {
  display: grid;
  gap: 0.55rem;
}

@media (min-width: 800px) {
  :root {
    font-size: 19px;
  }

  .group-box.compact .group-grid {
    max-width: none;
    grid-template-columns: repeat(12, minmax(0, 1fr));
  }

  .shell {
    padding-top: 1.25rem;
  }

  .cards {
    grid-template-columns: 1fr 1fr;
    align-items: stretch;
  }

  .activity-card {
    grid-template-columns: 1fr;
    min-height: 100%;
    align-items: start;
  }

  .explain-grid.pair {
    grid-template-columns: 1fr 1fr;
  }

  .two-col.pair {
    grid-template-columns: 1fr 1fr;
  }

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

  .panel {
    padding: 1.2rem 1.3rem 1.3rem;
  }
}

@media (min-width: 1200px) {
  :root {
    font-size: 20px;
  }
}

@media (max-width: 720px) {
  .stepper {
    grid-template-columns: 1fr 1fr;
  }

  .activity-card {
    grid-template-columns: 1fr;
  }

  h1 {
    font-size: 1.65rem;
  }

  .shell {
    width: min(1080px, calc(100% - 1rem));
  }
}

@media (prefers-reduced-motion: reduce) {
  * {
    scroll-behavior: auto !important;
    transition: none !important;
  }
}

@media print {
  body {
    background: #fff;
  }

  .top-actions,
  .nav-row,
  .record-actions,
  .stepper,
  .safety,
  .skip {
    display: none !important;
  }

  .panel {
    box-shadow: none;
    border: 1px solid #ccc;
  }
}