:root {
  --bg: #f4f5f8; --card: #ffffff; --ink: #161a22; --muted: #5b6372; --line: #dde1e8;
  --accent: #0f7b6c; --accent-ink: #ffffff; --accent-soft: #e0f3ef;
  --ok: #17803d; --ok-soft: #e3f5e8; --close: #9a6200; --close-soft: #fdf1dc; --bad: #b42318; --bad-soft: #fde8e6;
  --curve: #0f7b6c; --aud: #7a4ec2; --focus: #2457d6;
  color-scheme: light dark;
}
@media (prefers-color-scheme: dark) {
  :root {
    --bg: #101217; --card: #191c23; --ink: #eef0f4; --muted: #a2a9b6; --line: #2c313b;
    --accent: #3cc6ae; --accent-ink: #06231e; --accent-soft: #15322d;
    --ok: #56d483; --ok-soft: #15301f; --close: #f2b552; --close-soft: #33270f; --bad: #ff8a80; --bad-soft: #3a1a18;
    --curve: #3cc6ae; --aud: #b49cff; --focus: #8fb3ff;
  }
}
* { box-sizing: border-box; }
html { -webkit-text-size-adjust: 100%; }
body { margin: 0; font: 16px/1.5 -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif; background: var(--bg); color: var(--ink); padding-bottom: env(safe-area-inset-bottom); }
a { color: var(--accent); }
h1, h2 { line-height: 1.2; margin: 0 0 .5rem; }
h1 { font-size: 1.6rem; }
h2 { font-size: 1.2rem; margin-top: .5rem; }
:focus-visible { outline: 3px solid var(--focus); outline-offset: 2px; }
[tabindex="-1"]:focus, [tabindex="-1"]:focus-visible { outline: none; }
.sr-only { position: absolute; width: 1px; height: 1px; padding: 0; margin: -1px; overflow: hidden; clip: rect(0 0 0 0); white-space: nowrap; border: 0; }
.skip { position: absolute; left: -999px; top: 0; background: var(--card); padding: .5rem 1rem; z-index: 10; }
.skip:focus { left: .5rem; }

.top { display: flex; align-items: center; justify-content: space-between; gap: 1rem; padding: .75rem 1rem; padding-top: max(.75rem, env(safe-area-inset-top)); flex-wrap: wrap; max-width: 860px; margin: 0 auto; }
.brand { display: flex; align-items: center; gap: .5rem; font-weight: 700; font-size: 1.15rem; letter-spacing: -.01em; }
.top-right { display: flex; align-items: center; gap: 1rem; flex-wrap: wrap; }
.streak-chip { background: var(--accent-soft); color: var(--accent); font-weight: 600; font-size: .85rem; padding: .2rem .6rem; border-radius: 999px; }
.volume { display: flex; align-items: center; gap: .5rem; font-size: .9rem; }
.volume input { width: 120px; accent-color: var(--accent); }
.limiter { font-size: .75rem; color: var(--ok); border: 1px solid currentColor; border-radius: 4px; padding: 0 .35rem; white-space: nowrap; }

.tabs { display: flex; gap: .25rem; max-width: 860px; margin: 0 auto; padding: 0 1rem; border-bottom: 1px solid var(--line); overflow-x: auto; }
.tabs a { padding: .6rem .8rem; color: var(--muted); text-decoration: none; font-weight: 600; border-bottom: 3px solid transparent; white-space: nowrap; }
.tabs a[aria-current="page"] { color: var(--ink); border-bottom-color: var(--accent); }

main { max-width: 860px; margin: 0 auto; padding: 1rem; outline: none; }
.card { background: var(--card); border: 1px solid var(--line); border-radius: 14px; padding: 1.25rem; margin-bottom: 1rem; }
.card.note { padding: .75rem 1.25rem; font-size: .92rem; }
.card.note p { margin: 0; }
.hero h1 { font-size: 1.9rem; }
.lede { font-size: 1.05rem; color: var(--muted); margin-top: 0; }
.hint { color: var(--muted); font-size: .9rem; }
.msg { background: var(--accent-soft); border-radius: 8px; padding: .6rem .8rem; }
.row { display: flex; gap: .5rem; flex-wrap: wrap; margin-top: 1rem; }

.btn { display: inline-flex; align-items: center; justify-content: center; gap: .4rem; min-height: 44px; padding: .5rem 1rem; border-radius: 10px; border: 1px solid var(--line); background: var(--card); color: var(--ink); font: inherit; font-weight: 600; cursor: pointer; text-decoration: none; }
.btn:hover { border-color: var(--accent); }
.btn.primary { background: var(--accent); color: var(--accent-ink); border-color: var(--accent); }
.btn.big { min-height: 52px; font-size: 1.1rem; padding: .6rem 1.4rem; margin: .5rem 0; }
.btn.small { min-height: 34px; padding: .25rem .7rem; font-size: .88rem; }
.btn.danger { color: var(--bad); }
.btn[disabled] { opacity: .6; cursor: default; }
.btn[aria-pressed="true"] { background: var(--accent-soft); border-color: var(--accent); color: var(--ink); }
.btn.primary[aria-pressed="true"] { background: var(--accent); color: var(--accent-ink); }
.btn.file { position: relative; }
kbd { font: 600 .7rem/1 ui-monospace, SFMono-Regular, Menlo, monospace; border: 1px solid currentColor; border-radius: 4px; padding: .1rem .3rem; opacity: .6; margin-left: .35rem; }

.stats-row { display: flex; gap: .75rem; margin: 1rem 0; flex-wrap: wrap; }
.stat { flex: 1 1 80px; background: var(--bg); border-radius: 10px; padding: .75rem; text-align: center; }
.stat .num { display: block; font-size: 1.6rem; font-weight: 700; }
.stat .lbl { color: var(--muted); font-size: .85rem; }

.field { display: flex; align-items: center; gap: .6rem; flex-wrap: wrap; margin: .75rem 0; }
.field label { font-weight: 600; }
select, input[type="password"], input[type="text"] { font: inherit; min-height: 44px; padding: .4rem .6rem; border-radius: 8px; border: 1px solid var(--line); background: var(--card); color: var(--ink); }
input[type="range"] { accent-color: var(--accent); }

fieldset.modes { border: 0; padding: 0; margin: 0 0 .5rem; display: grid; grid-template-columns: repeat(auto-fill, minmax(150px, 1fr)); gap: .5rem; }
fieldset.modes legend { font-weight: 600; margin-bottom: .4rem; }
.mode { position: relative; display: flex; flex-direction: column; gap: .2rem; border: 1px solid var(--line); border-radius: 10px; padding: .6rem .7rem; cursor: pointer; }
.mode input { position: absolute; opacity: 0; }
.mode.on { border-color: var(--accent); background: var(--accent-soft); }
.mode:focus-within { outline: 3px solid var(--focus); outline-offset: 2px; }
.mode.locked { cursor: default; opacity: .7; }
.mode-title { font-weight: 700; }
.mode-blurb { font-size: .82rem; color: var(--muted); }
.tag { font-size: .7rem; background: var(--accent); color: var(--accent-ink); border-radius: 4px; padding: 0 .3rem; vertical-align: middle; }

.trainer-head { display: flex; justify-content: space-between; align-items: baseline; gap: .5rem; flex-wrap: wrap; }
.prompt { font-size: 1.15rem; font-weight: 600; margin: .25rem 0 1rem; }
.controls { display: flex; gap: .75rem; align-items: center; flex-wrap: wrap; margin-bottom: 1rem; }
.play { min-width: 130px; }
.ab { display: inline-flex; }
.ab .btn:first-child { border-radius: 10px 0 0 10px; }
.ab .btn:last-child { border-radius: 0 10px 10px 0; margin-left: -1px; }
.keys { font-size: .8rem; }

.bands { display: grid; gap: .4rem; margin: .5rem 0 1rem; }
.bands.octave { grid-template-columns: repeat(9, minmax(0, 1fr)); }
.bands.third { grid-template-columns: repeat(auto-fill, minmax(58px, 1fr)); }
.bands.gains { grid-template-columns: repeat(4, minmax(0, 1fr)); }
.band { min-height: 56px; border-radius: 10px; border: 1px solid var(--line); background: var(--bg); color: var(--ink); font: 700 1rem/1.1 inherit; cursor: pointer; display: flex; flex-direction: column; align-items: center; justify-content: center; gap: .2rem; padding: .3rem; }
.band kbd { margin: 0; font-size: .62rem; }
.band:hover { border-color: var(--accent); }
.band.is-picked { border-color: var(--accent); background: var(--accent-soft); }
.band.is-answer { border-color: var(--ok); background: var(--ok-soft); color: var(--ok); }
.band.is-wrong { border-color: var(--bad); background: var(--bad-soft); color: var(--bad); }
.band[aria-pressed="true"] { box-shadow: inset 0 0 0 3px var(--aud); }
.signs { display: flex; gap: .5rem; margin-bottom: 1rem; }

.feedback p { margin: .2rem 0; }
.feedback.correct p:first-child { color: var(--ok); font-weight: 700; }
.feedback.close p:first-child { color: var(--close); font-weight: 700; }
.feedback.wrong p:first-child { color: var(--bad); font-weight: 700; }
.curve { margin: .5rem 0 1rem; }
.curve svg { width: 100%; height: auto; background: var(--bg); border-radius: 10px; }
.curve .gl { stroke: var(--line); stroke-width: 1; }
.curve .gt { fill: var(--muted); font-size: 11px; }
.curve .zero { stroke: var(--muted); stroke-dasharray: 3 4; }
.curve .ans { fill: none; stroke: var(--curve); stroke-width: 3; }
.curve .aud { fill: none; stroke: var(--aud); stroke-width: 2; stroke-dasharray: 6 4; }

table { width: 100%; border-collapse: collapse; margin: .5rem 0; font-size: .95rem; }
caption { text-align: left; font-weight: 700; font-size: 1.05rem; padding-bottom: .4rem; }
th, td { text-align: left; padding: .45rem .4rem; border-bottom: 1px solid var(--line); }
thead th { color: var(--muted); font-weight: 600; font-size: .85rem; }
.results tr.ok td:nth-child(4) { color: var(--ok); font-weight: 600; }
.results tr.close td:nth-child(4) { color: var(--close); font-weight: 600; }
.results tr.miss td:nth-child(4) { color: var(--bad); font-weight: 600; }
.acc { display: inline-flex; align-items: center; gap: .5rem; }
.bar { display: inline-block; width: 120px; max-width: 30vw; height: 8px; background: var(--line); border-radius: 4px; position: relative; overflow: hidden; }
.bar::after { content: ""; position: absolute; inset: 0 auto 0 0; width: var(--pct, 0%); background: var(--accent); border-radius: 4px; }

.license label { display: block; font-weight: 600; margin-bottom: .3rem; }
.key-row { display: flex; gap: .5rem; margin-bottom: .75rem; }
.key-row input { flex: 1; min-width: 0; font-family: ui-monospace, SFMono-Regular, Menlo, monospace; }
.ticks { padding-left: 1.2rem; }
.ticks li { margin: .3rem 0; }
.songs { border-top: 1px solid var(--line); margin-top: .5rem; padding-top: .5rem; }
.song-list { list-style: none; padding: 0; margin: .5rem 0; }
.song-list li { display: flex; justify-content: space-between; align-items: center; gap: .5rem; padding: .3rem 0; border-bottom: 1px solid var(--line); }
.keys-list { display: grid; grid-template-columns: max-content 1fr; gap: .4rem 1rem; }
.keys-list dd { margin: 0; }

dialog { border: 1px solid var(--line); border-radius: 14px; background: var(--card); color: var(--ink); max-width: 520px; padding: 1.5rem; }
dialog::backdrop { background: rgb(0 0 0 / .55); }
dialog li { margin: .4rem 0; }

@media (max-width: 560px) {
  .bands.octave { grid-template-columns: repeat(5, minmax(0, 1fr)); }
  .hero h1 { font-size: 1.6rem; }
  .volume input { width: 90px; }
  .top { gap: .5rem; }
  .tabs { padding: 0 .5rem; gap: 0; }
  .tabs a { padding: .6rem .5rem; font-size: .95rem; }
  .stat { padding: .6rem .3rem; }
}
@media (prefers-reduced-motion: reduce) { * { transition: none !important; animation: none !important; } }