:root {
  --bg: #10141b;
  --bg-soft: #171d28;
  --card: #1c2330;
  --line: #2b3547;
  --text: #e8edf5;
  --muted: #9aa7bd;
  --accent: #5cc8ff;
  --accent-ink: #06222f;
  --good: #4ade80;
  --bad: #f87171;
  --warn: #fbbf24;
  --radius: 12px;
}
:root[data-theme="light"] {
  --bg: #f4f6fa;
  --bg-soft: #ffffff;
  --card: #ffffff;
  --line: #d9e0ec;
  --text: #16202e;
  --muted: #5b6b82;
  --accent: #0369a1;
  --accent-ink: #ffffff;
}
* { box-sizing: border-box; }
html, body { margin: 0; padding: 0; }
body {
  background: var(--bg);
  color: var(--text);
  font: 16px/1.5 -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
  max-width: 960px;
  margin: 0 auto;
  padding: 0 16px 64px;
}
.topbar {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  align-items: center;
  justify-content: space-between;
  padding: 20px 0 8px;
  border-bottom: 1px solid var(--line);
  margin-bottom: 16px;
}
.brand { display: flex; gap: 12px; align-items: center; }
.cube { font-size: 40px; color: var(--accent); }
.brand h1 { font-size: 22px; margin: 0; }
.tagline { margin: 0; color: var(--muted); font-size: 13px; }
.tabs { display: flex; flex-wrap: wrap; gap: 6px; }
.tabs button {
  background: var(--bg-soft);
  color: var(--text);
  border: 1px solid var(--line);
  border-radius: 999px;
  padding: 8px 14px;
  cursor: pointer;
  font-size: 14px;
}
.tabs button.active { background: var(--accent); border-color: var(--accent); color: var(--accent-ink); font-weight: 700; }
.panel { display: none; }
.panel.active { display: block; }
h2 { margin: 12px 0 4px; }
.muted { color: var(--muted); }
.card {
  background: var(--card);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 20px;
  margin: 12px 0;
}
.controls { display: flex; flex-wrap: wrap; gap: 10px; align-items: end; margin: 12px 0; }
.controls label { display: grid; gap: 4px; font-size: 13px; color: var(--muted); }
.controls label.grow { flex: 1; min-width: 200px; }
input, select, textarea, button {
  font: inherit;
  border-radius: 8px;
  border: 1px solid var(--line);
  background: var(--bg-soft);
  color: var(--text);
  padding: 8px 10px;
}
button { cursor: pointer; }
button.primary { background: var(--accent); border-color: var(--accent); color: var(--accent-ink); font-weight: 700; }
button.ghost { background: transparent; }
button.danger { border-color: var(--bad); color: var(--bad); background: transparent; }
button:disabled { opacity: 0.45; cursor: default; }
.check { display: flex !important; flex-direction: row !important; align-items: center; gap: 6px !important; }
.row { display: flex; flex-wrap: wrap; gap: 10px; align-items: center; margin: 10px 0; }
.seg { display: inline-flex; border: 1px solid var(--line); border-radius: 999px; overflow: hidden; margin: 8px 0; }
.seg-btn { border: 0; border-radius: 0; background: transparent; padding: 8px 18px; }
.seg-btn.active { background: var(--accent); color: var(--accent-ink); font-weight: 700; }
.learn-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(150px, 1fr)); gap: 10px; margin: 12px 0; }
.face-block { background: var(--card); border: 1px solid var(--line); border-radius: var(--radius); padding: 10px; }
.face-block h3 { margin: 0 0 8px; font-size: 14px; color: var(--muted); }
.sticker {
  display: flex;
  justify-content: space-between;
  padding: 4px 8px;
  border-radius: 6px;
  margin: 2px 0;
  background: var(--bg-soft);
  font-size: 14px;
}
.sticker .letter { font-weight: 800; color: var(--accent); }
.sticker.buffer { outline: 2px solid var(--warn); }
.scorebar { display: flex; gap: 16px; align-items: center; margin: 8px 0; flex-wrap: wrap; }
.drill-q { font-size: 30px; font-weight: 800; margin: 8px 0 14px; letter-spacing: 0.5px; }
.opts { display: grid; grid-template-columns: repeat(auto-fit, minmax(140px, 1fr)); gap: 8px; margin-bottom: 10px; }
.opts button { padding: 12px; font-size: 16px; }
.opts button.right { border-color: var(--good); background: rgba(74, 222, 128, 0.15); }
.opts button.wrong { border-color: var(--bad); background: rgba(248, 113, 113, 0.15); }
.letterpad { display: grid; grid-template-columns: repeat(auto-fit, minmax(40px, 1fr)); gap: 6px; margin-bottom: 10px; }
.letterpad button { padding: 8px 0; font-weight: 700; }
.typerow { display: flex; gap: 8px; margin-bottom: 10px; }
.typerow input { width: 90px; text-transform: uppercase; font-size: 20px; text-align: center; font-weight: 800; }
.feedback { min-height: 26px; margin: 8px 0; font-weight: 600; }
.feedback.good { color: var(--good); }
.feedback.bad { color: var(--bad); }
.hidden { display: none !important; }
.pairs-list { list-style: none; padding: 0; margin: 12px 0; display: grid; gap: 6px; }
.pairs-list li {
  display: flex; gap: 10px; align-items: center;
  background: var(--card); border: 1px solid var(--line);
  border-radius: 8px; padding: 8px 12px;
}
.pairs-list .pk { font-weight: 800; font-size: 18px; color: var(--accent); min-width: 48px; }
.pairs-list .pw { flex: 1; }
.memo-seq { font-size: 34px; font-weight: 800; letter-spacing: 6px; margin: 8px 0; word-spacing: 12px; }
.memo-hints { display: flex; flex-wrap: wrap; gap: 8px; margin-bottom: 8px; }
.memo-hints span { background: var(--bg-soft); border: 1px solid var(--line); border-radius: 8px; padding: 4px 10px; font-size: 14px; }
.recall-label { display: grid; gap: 6px; margin-top: 12px; color: var(--muted); font-size: 13px; }
.recall-label input { text-transform: uppercase; font-size: 22px; letter-spacing: 4px; font-weight: 700; }
.char { display: inline-block; min-width: 26px; text-align: center; border-radius: 6px; padding: 2px 4px; margin: 0 1px; }
.char.ok { background: rgba(74, 222, 128, 0.2); color: var(--good); }
.char.miss { background: rgba(248, 113, 113, 0.2); color: var(--bad); text-decoration: underline; }
.scramble { font-size: 18px; background: var(--card); border: 1px solid var(--line); border-radius: var(--radius); padding: 12px 16px; margin: 12px 0; letter-spacing: 1px; }
.time-display { font-size: 72px; font-weight: 800; text-align: center; font-variant-numeric: tabular-nums; margin: 8px 0; }
.time-display.armed { color: var(--good); }
.time-display.running { color: var(--accent); }
.timer-pad {
  user-select: none; -webkit-user-select: none; touch-action: none;
  text-align: center; padding: 22px; border: 2px dashed var(--line);
  border-radius: var(--radius); color: var(--muted); font-weight: 800; letter-spacing: 2px;
  margin-bottom: 12px;
}
.timer-pad.armed { border-color: var(--good); color: var(--good); }
.stats { display: flex; gap: 18px; flex-wrap: wrap; margin: 12px 0; }
.times-list { padding-left: 24px; }
.times-list li { cursor: pointer; padding: 2px 0; font-variant-numeric: tabular-nums; }
kbd { background: var(--bg-soft); border: 1px solid var(--line); border-bottom-width: 2px; border-radius: 6px; padding: 1px 7px; font-size: 13px; }
#cube-wrap { height: 440px; background: var(--bg-soft); border: 1px solid var(--line); border-radius: var(--radius); overflow: hidden; margin: 12px 0; }
#cube-wrap canvas { width: 100%; height: 100%; display: block; touch-action: none; }
#piece-wrap { height: 360px; background: var(--bg-soft); border: 1px solid var(--line); border-radius: var(--radius); overflow: hidden; margin: 12px 0; position: relative; }
#piece-wrap canvas { width: 100%; height: 100%; display: block; touch-action: none; }
.piece-legend { display:flex; gap:8px; flex-wrap:wrap; margin:4px 0; }
.piece-legend span { font-size:12px; padding:2px 8px; border-radius:999px; border:1px solid var(--line); background:var(--bg-soft); }
#data-box { width: 100%; margin-top: 8px; font-family: ui-monospace, monospace; font-size: 12px; }
.cardback { cursor: pointer; }
.cardback .letter { color: var(--muted); }
.scheme-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(150px, 1fr)); gap: 10px; margin: 8px 0; }
.scheme-face { background: var(--card); border: 1px solid var(--line); border-radius: 8px; padding: 8px; }
.scheme-face h4 { margin: 0 0 6px; color: var(--muted); font-size: 13px; }
.scheme-face label { display: inline-flex; align-items: center; gap: 4px; margin: 0 8px 6px 0; font-size: 13px; }
.scheme-face input { width: 38px; text-align: center; text-transform: uppercase; font-weight: 800; }
footer { margin-top: 32px; padding-top: 12px; border-top: 1px solid var(--line); color: var(--muted); font-size: 13px; }
@media (max-width: 560px) {
  #cube-wrap { height: 330px; }
  #piece-wrap { height: 300px; }
  .time-display { font-size: 56px; }
  .drill-q { font-size: 24px; }
  .memo-seq { font-size: 26px; }
}