:root {
  --ink: #1c1917;
  --muted: #57534e;
  --paper: #faf6ef;
  --panel: #fffdf8;
  --accent: #0f766e;
  --accent-deep: #115e59;
  --warm: #c2410c;
  --ok: #15803d;
  --warn: #b45309;
  --line: #e7e0d4;
  --hl: #fef08a;
  --shadow: 0 8px 24px rgba(28, 25, 23, 0.08);
  --radius: 20px;
  --font: "PingFang SC", "Hiragino Sans GB", "Noto Sans SC", "Microsoft YaHei", sans-serif;
}

* { box-sizing: border-box; }
html, body { margin: 0; padding: 0; }
body {
  min-height: 100vh;
  font-family: var(--font);
  color: var(--ink);
  background:
    radial-gradient(900px 400px at 10% -10%, #d9f0ea 0%, transparent 55%),
    radial-gradient(700px 360px at 100% 0%, #ffe8cc 0%, transparent 50%),
    var(--paper);
  -webkit-tap-highlight-color: transparent;
}

.wrap {
  width: min(720px, 100%);
  margin: 0 auto;
  padding: 20px 14px 64px;
}

.app-header h1 {
  margin: 0 0 6px;
  font-size: clamp(1.9rem, 6vw, 2.4rem);
  letter-spacing: 0.04em;
}
.app-header p {
  margin: 0;
  color: var(--muted);
  font-size: 1.15rem;
  line-height: 1.5;
}

.nav-tabs {
  display: flex;
  gap: 10px;
  margin: 18px 0 0;
}
.nav-tabs button {
  flex: 1;
  min-height: 52px;
  border: 2px solid var(--line);
  background: #fff;
  color: var(--muted);
  border-radius: 999px;
  padding: 10px 12px;
  font: inherit;
  font-size: 1.2rem;
  font-weight: 700;
  cursor: pointer;
}
.nav-tabs button.active {
  background: #ccfbf1;
  color: var(--accent-deep);
  border-color: #5eead4;
}

.card-list {
  display: grid;
  gap: 14px;
  margin-top: 18px;
}
.card {
  display: block;
  background: var(--panel);
  border: 2px solid var(--line);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  padding: 22px 18px;
  color: inherit;
  text-decoration: none;
  min-height: 96px;
}
.card:active { transform: scale(0.99); }
.card h2 {
  margin: 0 0 8px;
  font-size: 1.55rem;
}
.card .meta {
  color: var(--muted);
  font-size: 1.1rem;
  line-height: 1.45;
}

.footer-note {
  margin: 22px 4px 0;
  color: var(--muted);
  font-size: 1rem;
  line-height: 1.5;
}

.back {
  display: inline-flex;
  align-items: center;
  min-height: 48px;
  border: 0;
  background: transparent;
  color: var(--accent-deep);
  font: inherit;
  font-size: 1.2rem;
  font-weight: 700;
  padding: 0;
  cursor: pointer;
  margin: 8px 0 4px;
}

#play-title {
  margin: 4px 0 0;
  font-size: 1.5rem;
}
.progress-text {
  margin: 6px 0 0;
  color: var(--muted);
  font-size: 1.15rem;
}

.panel {
  margin-top: 14px;
  background: var(--panel);
  border: 2px solid var(--line);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  padding: 18px 14px 20px;
}

.guide {
  margin: 0 0 14px;
  font-size: 1.25rem;
  color: var(--muted);
  text-align: center;
}

.char-row {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: 10px;
  min-height: 140px;
  padding: 8px 0 16px;
}

.char-tile {
  width: min(22vw, 92px);
  min-width: 72px;
  border: 3px solid #d6d3d1;
  background: #fff;
  border-radius: 16px;
  padding: 8px 4px 10px;
  cursor: pointer;
  text-align: center;
  font: inherit;
  color: inherit;
  box-shadow: 0 2px 0 #e7e5e4;
}
.char-tile:active { transform: translateY(1px); }
.char-tile.active {
  border-color: #ca8a04;
  background: var(--hl);
  box-shadow: 0 0 0 4px rgba(250, 204, 21, 0.35);
}
.char-tile.punct {
  border-style: dashed;
  opacity: 0.75;
  min-width: 56px;
  width: 56px;
}
.char-tile .py {
  display: block;
  font-size: 0.95rem;
  color: var(--warm);
  line-height: 1.2;
  min-height: 1.2em;
  margin-bottom: 2px;
}
.char-tile .han {
  display: block;
  font-size: clamp(2.4rem, 9vw, 3.2rem);
  font-weight: 700;
  line-height: 1.15;
}

.selected-tip {
  text-align: center;
  font-size: 1.35rem;
  margin: 0 0 12px;
  color: var(--accent-deep);
  font-weight: 700;
}

.controls {
  display: grid;
  gap: 12px;
  margin-top: 8px;
}
.controls.twin {
  grid-template-columns: 1fr 1fr;
}

.btn {
  min-height: 64px;
  border: 0;
  border-radius: 18px;
  font: inherit;
  font-size: 1.35rem;
  font-weight: 800;
  cursor: pointer;
  padding: 12px 14px;
}
.btn:disabled {
  opacity: 0.45;
  cursor: not-allowed;
}
.btn-main {
  background: var(--accent);
  color: #fff;
}
.btn-main:active:not(:disabled) { background: var(--accent-deep); }
.btn-slow { background: #0e7490; }
.btn-ok {
  background: #dcfce7;
  color: var(--ok);
  border: 2px solid #86efac;
}
.btn-warn {
  background: #ffedd5;
  color: var(--warn);
  border: 2px solid #fdba74;
}

.unknown-list {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(110px, 1fr));
  gap: 12px;
}
.unknown-card {
  border: 3px solid var(--line);
  background: #fff;
  border-radius: 16px;
  padding: 12px 8px;
  text-align: center;
}
.unknown-card .han {
  font-size: 2.8rem;
  font-weight: 800;
  line-height: 1.2;
}
.unknown-card .py {
  color: var(--warm);
  font-size: 1.05rem;
  margin: 4px 0 10px;
}
.unknown-card .actions {
  display: grid;
  gap: 8px;
}
.unknown-card button {
  min-height: 44px;
  border-radius: 12px;
  border: 0;
  font: inherit;
  font-size: 1.05rem;
  font-weight: 700;
  cursor: pointer;
}
.unknown-card .hear {
  background: #ccfbf1;
  color: var(--accent-deep);
}
.unknown-card .got {
  background: #dcfce7;
  color: var(--ok);
}

.empty {
  text-align: center;
  color: var(--muted);
  font-size: 1.2rem;
  padding: 28px 10px;
}