:root {
  --bg: #f7f6f3; --card: #fff; --fg: #1d1d1f; --muted: #6b6b70; --line: #e2e0da;
  --accent: #3a5bd9; --accent-fg: #fff; --air: #3a8fd9; --bone: #d9733a; --ratio: #2f9e5b;
}
@media (prefers-color-scheme: dark) {
  :root { --bg: #151517; --card: #1f1f22; --fg: #ececee; --muted: #9a9aa2; --line: #333338; --accent: #6d8bff; }
}
* { box-sizing: border-box; }
body { margin: 0; background: var(--bg); color: var(--fg); font: 16px/1.45 system-ui, -apple-system, sans-serif; }
header, main, footer { max-width: 760px; margin: 0 auto; padding: 0 16px; }
h1 { margin: 20px 0 4px; font-size: 26px; }
h2 { margin-top: 0; font-size: 20px; }
.muted { color: var(--muted); }
.small { font-size: 14px; }
nav { display: flex; flex-wrap: wrap; gap: 6px; margin: 12px 0; }
nav button { font-size: 14px; padding: 6px 10px; }
nav button.on { background: var(--accent); color: var(--accent-fg); border-color: var(--accent); }
.tab { display: none; background: var(--card); border: 1px solid var(--line); border-radius: 12px; padding: 18px; margin-bottom: 16px; }
.tab.on { display: block; }
button { font: inherit; padding: 9px 14px; border-radius: 9px; border: 1px solid var(--line); background: var(--card); color: var(--fg); cursor: pointer; }
button:disabled { opacity: .45; cursor: default; }
button.primary { background: var(--accent); color: var(--accent-fg); border-color: var(--accent); }
button.ghost { background: transparent; }
button.big { font-size: 22px; padding: 18px; flex: 1; }
.row, .ab { display: flex; flex-wrap: wrap; gap: 8px; align-items: center; margin: 12px 0; }
.ab button { flex: 1; min-width: 90px; }
.grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(220px, 1fr)); gap: 12px; margin-bottom: 12px; }
label { display: flex; flex-direction: column; gap: 4px; font-size: 14px; }
label.check { flex-direction: row; align-items: center; gap: 8px; margin: 12px 0; }
input, select { font: inherit; padding: 7px; border-radius: 8px; border: 1px solid var(--line); background: var(--bg); color: var(--fg); }
input[type=range] { padding: 0; width: 100%; }
.meter, .progress { height: 8px; background: var(--line); border-radius: 4px; overflow: hidden; margin: 8px 0; }
#meterBar, #matchBar { height: 100%; width: 0; background: var(--accent); transition: width .1s; }
.slider { display: grid; grid-template-columns: 1fr 70px; gap: 2px 10px; margin: 10px 0; }
.slider .v { text-align: right; font-variant-numeric: tabular-nums; }
.slider input { grid-column: 1 / -1; }
pre { background: var(--bg); padding: 12px; border-radius: 8px; overflow-x: auto; font-size: 13px; white-space: pre-wrap; }
canvas { width: 100%; height: 220px; background: var(--bg); border-radius: 8px; }
.sw { display: inline-block; width: 12px; height: 3px; margin: 0 4px 3px 10px; }
.sw.air { background: var(--air); } .sw.bone { background: var(--bone); } .sw.ratio { background: var(--ratio); }
footer { padding-bottom: 24px; }
.top { display: flex; justify-content: space-between; align-items: center; gap: 12px; flex-wrap: wrap; }
.lang { flex-direction: row; align-items: center; gap: 6px; }
label.grow { flex: 1; min-width: 200px; }
.explain { border: 1px solid var(--line); border-radius: 10px; padding: 10px 14px; margin: 12px 0; background: var(--bg); }
.explain summary { cursor: pointer; display: flex; flex-direction: column; gap: 2px; }
.explain summary::marker { content: ''; }
.explain summary b::before { content: '▸ '; }
.explain[open] summary b::before { content: '▾ '; }
.explain-body h3 { font-size: 15px; margin: 14px 0 4px; }
.explain-body p { margin: 4px 0; }
.pair { border: 2px solid var(--line); border-radius: 12px; padding: 12px; margin: 10px 0; }
.pair.fresh { animation: fresh .6s ease; }
@keyframes fresh { from { border-color: var(--accent); transform: translateY(6px); opacity: .4; } to { transform: none; opacity: 1; } }
.pair-head { display: flex; gap: 10px; align-items: baseline; flex-wrap: wrap; }
.hint { margin: 8px 0 0; padding: 10px 12px; border-radius: 8px; background: var(--bg); font-weight: 600; text-align: center; }
.hint.ok { color: var(--ratio); }
.pulse { box-shadow: 0 0 0 0 var(--accent); animation: pulse 1.3s infinite; border-color: var(--accent); }
@keyframes pulse { 0% { box-shadow: 0 0 0 0 color-mix(in srgb, var(--accent) 60%, transparent); } 70% { box-shadow: 0 0 0 10px transparent; } 100% { box-shadow: 0 0 0 0 transparent; } }
button.playing { background: var(--accent); color: var(--accent-fg); }
button.heard { border-color: var(--ratio); }
.history { display: flex; flex-wrap: wrap; gap: 4px; }
.history span { font-size: 12px; padding: 2px 7px; border-radius: 10px; background: var(--bg); border: 1px solid var(--line); font-variant-numeric: tabular-nums; }
.history span.sep { border: none; background: none; color: var(--muted); }