/* ==========================================================================
   Music Trainer — theme tokens
   ========================================================================== */
:root {
  --bg: #f3efe7;
  --bg-2: #eae4d8;
  --surface: #fffdf9;
  --surface-2: #f6f1e8;
  --line: #d9d1c2;
  --text: #201c17;
  --muted: #6e6659;
  --accent: #b5432a;
  --accent-soft: #f3d9d1;
  --accent-2: #2b5e9c;
  --gold: #b0842b;
  --gold-soft: #f4e8cc;
  --green: #2f7a4d;
  --sheet: #fffdf8;
  --sheet-ink: #1a1712;
  --hl: #d9480f;
  --kb-white: #fbfaf5;
  --kb-white-line: #b8b0a2;
  --kb-black: #2b2622;
  --kb-on: #f39b3b;
  --kb-on-black: #ff7d1f;
  --chord: #2b5e9c;
  --chord-ink: #2b5e9c;
  --kb-chord: #cfe0f7;
  --kb-chord-line: #4f83c9;
  --kb-chord-black: #3f74bf;
  --shadow: 0 1px 2px rgba(20, 12, 4, 0.06), 0 10px 28px -14px rgba(30, 20, 10, 0.28);
  --font-serif: "Fraunces", "Iowan Old Style", "Palatino Linotype", "Book Antiqua", Georgia, serif;
  --font-sans: "Inter", system-ui, -apple-system, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
  --font-mono: ui-monospace, "Cascadia Code", "JetBrains Mono", Consolas, "Liberation Mono", monospace;
  --radius: 14px;
  --sidebar-w: 292px;
  color-scheme: light;
}

@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) {
    --bg: #15120f;
    --bg-2: #1b1815;
    --surface: #211d19;
    --surface-2: #29241f;
    --line: #3b342c;
    --text: #ebe4d8;
    --muted: #a89f91;
    --accent: #f0865d;
    --accent-soft: #46271d;
    --accent-2: #86b4f2;
    --gold: #dfb35a;
    --gold-soft: #3a2f16;
    --green: #6fc08c;
    --sheet: #f9f5ec;
    --sheet-ink: #1a1712;
    --hl: #e2580f;
    --kb-white: #ece7dc;
    --kb-white-line: #a19a8d;
    --kb-black: #16120f;
    --kb-on: #f39b3b;
    --kb-on-black: #ff7d1f;
    --chord: #3f74bf;
    --chord-ink: #8fbbf5;
    --kb-chord: #a9c4e8;
    --kb-chord-line: #4f83c9;
    --kb-chord-black: #4f83c9;
    --shadow: 0 1px 2px rgba(0, 0, 0, 0.3), 0 12px 32px -14px rgba(0, 0, 0, 0.6);
    color-scheme: dark;
  }
}
:root[data-theme="dark"] {
  --bg: #15120f;
  --bg-2: #1b1815;
  --surface: #211d19;
  --surface-2: #29241f;
  --line: #3b342c;
  --text: #ebe4d8;
  --muted: #a89f91;
  --accent: #f0865d;
  --accent-soft: #46271d;
  --accent-2: #86b4f2;
  --gold: #dfb35a;
  --gold-soft: #3a2f16;
  --green: #6fc08c;
  --sheet: #f9f5ec;
  --sheet-ink: #1a1712;
  --hl: #e2580f;
  --kb-white: #ece7dc;
  --kb-white-line: #a19a8d;
  --kb-black: #16120f;
  --kb-on: #f39b3b;
  --kb-on-black: #ff7d1f;
  --chord: #3f74bf;
  --chord-ink: #8fbbf5;
  --kb-chord: #a9c4e8;
  --kb-chord-line: #4f83c9;
  --kb-chord-black: #4f83c9;
  --shadow: 0 1px 2px rgba(0, 0, 0, 0.3), 0 12px 32px -14px rgba(0, 0, 0, 0.6);
  color-scheme: dark;
}

/* ==========================================================================
   Base
   ========================================================================== */
* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  margin: 0;
  background: var(--bg);
  color: var(--text);
  font-family: var(--font-sans);
  font-size: 16px;
  line-height: 1.62;
  -webkit-font-smoothing: antialiased;
}
a { color: var(--accent-2); }
h1, h2, h3, h4 { font-family: var(--font-serif); font-weight: 600; line-height: 1.18; letter-spacing: -0.01em; margin: 0; }
h1 { font-size: clamp(2rem, 4.2vw, 2.9rem); }
h2 { font-size: 1.6rem; margin-top: 2.4rem; margin-bottom: 0.6rem; }
h3 { font-size: 1.25rem; margin-top: 1.6rem; margin-bottom: 0.4rem; }
p { margin: 0 0 1em; }
ul, ol { padding-left: 1.3em; margin: 0 0 1em; }
li { margin-bottom: 0.35em; }
code, pre { font-family: var(--font-mono); font-size: 0.92em; }
code { background: var(--surface-2); padding: 0.1em 0.35em; border-radius: 5px; border: 1px solid var(--line); }
pre code { background: none; border: 0; padding: 0; }
pre { background: var(--surface-2); border: 1px solid var(--line); border-radius: 10px; padding: 12px 14px; overflow: auto; line-height: 1.5; }
strong { font-weight: 600; }
.muted { color: var(--muted); }
.eyebrow { font-size: 0.74rem; letter-spacing: 0.12em; text-transform: uppercase; color: var(--muted); font-weight: 600; }
.lead { font-size: 1.16rem; color: var(--muted); max-width: 62ch; }
hr { border: 0; border-top: 1px solid var(--line); margin: 2rem 0; }
table { border-collapse: collapse; width: 100%; font-size: 0.95rem; margin: 0 0 1.4em; }
th, td { text-align: left; vertical-align: top; padding: 8px 10px; border-bottom: 1px solid var(--line); }
th { font-weight: 600; font-size: 0.82rem; letter-spacing: 0.04em; text-transform: uppercase; color: var(--muted); }
button { font: inherit; color: inherit; }
kbd { font-family: var(--font-mono); font-size: 0.85em; padding: 0.1em 0.4em; border: 1px solid var(--line); border-bottom-width: 2px; border-radius: 5px; background: var(--surface); }

.btn {
  display: inline-flex; align-items: center; gap: 8px;
  padding: 9px 16px; border-radius: 999px; border: 1px solid var(--line);
  background: var(--surface); color: var(--text); cursor: pointer; font-weight: 500; font-size: 0.95rem;
  text-decoration: none; transition: background 0.15s, border-color 0.15s, transform 0.1s;
}
.btn:hover { border-color: var(--muted); background: var(--surface-2); }
.btn:active { transform: translateY(1px); }
.btn.primary { background: var(--accent); border-color: var(--accent); color: #fff; }
.btn.primary:hover { filter: brightness(1.06); }
.btn.small { padding: 6px 12px; font-size: 0.85rem; }
.btn .ico { width: 16px; height: 16px; fill: currentColor; }

/* ==========================================================================
   Layout
   ========================================================================== */
.app { display: grid; grid-template-columns: var(--sidebar-w) minmax(0, 1fr); min-height: 100vh; }
.sidebar {
  position: sticky; top: 0; height: 100vh; overflow-y: auto;
  background: var(--bg-2); border-right: 1px solid var(--line);
  padding: 22px 16px 40px;
}
.brand { display: flex; align-items: center; gap: 10px; text-decoration: none; color: inherit; padding: 4px 6px 18px; }
.brand .logo { width: 38px; height: 38px; border-radius: 10px; background: var(--accent); color: #fff; display: grid; place-items: center; font-family: var(--font-serif); font-size: 1.5rem; font-weight: 700; }
.brand .name { font-family: var(--font-serif); font-size: 1.15rem; font-weight: 600; line-height: 1.1; }
.brand .tag { font-size: 0.72rem; color: var(--muted); }
.nav { display: flex; flex-direction: column; gap: 2px; }
.nav-mod { margin-top: 16px; }
.nav-mod > .eyebrow { padding: 0 8px 6px; display: block; }
.nav a {
  display: grid; grid-template-columns: 1.7em 1fr auto; align-items: center; gap: 6px;
  padding: 7px 8px; border-radius: 9px; color: inherit; text-decoration: none; font-size: 0.93rem; line-height: 1.3;
}
.nav a:hover { background: var(--surface); }
.nav a.active { background: var(--surface); box-shadow: inset 0 0 0 1px var(--line); color: var(--accent); font-weight: 600; }
.nav .num { color: var(--muted); font-variant-numeric: tabular-nums; font-size: 0.8rem; }
.nav .check { color: var(--green); font-size: 0.85rem; opacity: 0; }
.nav a.done .check { opacity: 1; }
.nav .extra { margin-top: 18px; padding-top: 12px; border-top: 1px solid var(--line); }
.progress-line { margin: 18px 8px 0; font-size: 0.78rem; color: var(--muted); }
.progress-line .bar { height: 5px; background: var(--surface); border-radius: 3px; overflow: hidden; margin-top: 6px; border: 1px solid var(--line); }
.progress-line .bar i { display: block; height: 100%; background: var(--green); width: 0; transition: width 0.4s; }

.main { min-width: 0; }
.topbar {
  position: sticky; top: 0; z-index: 8;
  display: flex; align-items: center; gap: 12px;
  padding: 10px 22px; border-bottom: 1px solid var(--line);
  background: color-mix(in srgb, var(--bg) 82%, transparent);
  backdrop-filter: blur(10px); -webkit-backdrop-filter: blur(10px);
}
.topbar .crumbs { font-size: 0.86rem; color: var(--muted); min-width: 0; overflow: hidden; text-overflow: ellipsis; white-space: nowrap; }
.topbar .crumbs a { color: inherit; text-decoration: none; }
.topbar .crumbs a:hover { color: var(--accent); }
.topbar .spacer { flex: 1; }
.icon-btn { display: inline-grid; place-items: center; width: 36px; height: 36px; border-radius: 10px; border: 1px solid var(--line); background: var(--surface); cursor: pointer; }
.icon-btn:hover { border-color: var(--muted); }
.icon-btn svg { width: 18px; height: 18px; fill: none; stroke: currentColor; stroke-width: 2; stroke-linecap: round; stroke-linejoin: round; }
.nav-toggle { display: none; }
.content { max-width: 940px; margin: 0 auto; padding: 34px 26px 110px; }
.scrim { position: fixed; inset: 0; background: rgba(0, 0, 0, 0.35); opacity: 0; pointer-events: none; transition: opacity 0.2s; z-index: 15; }

@media (max-width: 960px) {
  .app { grid-template-columns: 1fr; }
  .sidebar { position: fixed; inset: 0 auto 0 0; width: min(86vw, 330px); transform: translateX(-102%); transition: transform 0.25s ease; z-index: 20; box-shadow: var(--shadow); }
  .sidebar.open { transform: none; }
  .scrim.show { opacity: 1; pointer-events: auto; }
  .nav-toggle { display: inline-grid; }
  .content { padding: 22px 16px 90px; }
}

/* ==========================================================================
   Home
   ========================================================================== */
.hero { padding: 26px 0 18px; }
.hero h1 { max-width: 16ch; }
.hero .lead { margin-top: 14px; }
.hero .actions { display: flex; gap: 12px; flex-wrap: wrap; margin-top: 22px; }
.feature-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(210px, 1fr)); gap: 14px; margin: 26px 0 8px; }
.feature { background: var(--surface); border: 1px solid var(--line); border-radius: var(--radius); padding: 16px 18px; }
.feature h3 { margin: 6px 0 4px; font-size: 1.05rem; }
.feature p { margin: 0; font-size: 0.92rem; color: var(--muted); }
.feature .glyph { font-family: var(--font-serif); font-size: 1.6rem; color: var(--accent); line-height: 1; }
.cards { display: grid; grid-template-columns: repeat(auto-fill, minmax(250px, 1fr)); gap: 14px; margin: 12px 0 30px; }
.card { display: block; text-decoration: none; color: inherit; background: var(--surface); border: 1px solid var(--line); border-radius: var(--radius); padding: 16px 18px; transition: transform 0.15s, box-shadow 0.15s, border-color 0.15s; }
.card:hover { transform: translateY(-2px); box-shadow: var(--shadow); border-color: var(--muted); }
.card h3 { font-size: 1.12rem; margin: 6px 0 4px; }
.card p { font-size: 0.9rem; color: var(--muted); margin: 0 0 8px; }
.card .piece { font-size: 0.82rem; color: var(--gold); font-weight: 600; }
.card .done-badge { float: right; color: var(--green); font-size: 0.8rem; font-weight: 600; }

/* ==========================================================================
   Lesson
   ========================================================================== */
.lesson-head { padding-bottom: 20px; border-bottom: 1px solid var(--line); margin-bottom: 28px; }
.lesson-head .eyebrow { margin-bottom: 10px; display: block; }
.lesson-head .lead { margin-top: 12px; }
.lesson-head .meta { display: flex; flex-wrap: wrap; gap: 8px; margin-top: 16px; }
.pill { display: inline-flex; align-items: center; gap: 6px; padding: 4px 11px; border-radius: 999px; background: var(--surface); border: 1px solid var(--line); font-size: 0.8rem; color: var(--muted); }
.pill.gold { color: var(--gold); border-color: color-mix(in srgb, var(--gold) 45%, var(--line)); background: var(--gold-soft); }
.lesson-body > p, .lesson-body > ul, .lesson-body > ol, .lesson-body > h2, .lesson-body > h3, .lesson-body > table { max-width: 72ch; }
.lesson-body h2 { display: flex; align-items: baseline; gap: 10px; }
.lesson-body h2::before { content: ""; width: 26px; height: 3px; background: var(--accent); border-radius: 2px; flex: none; position: relative; top: -4px; }
.note { font-family: var(--font-serif); font-style: italic; }

.callout { border-radius: 12px; padding: 14px 18px; margin: 22px 0; border: 1px solid var(--line); background: var(--surface); max-width: 74ch; }
.callout h4 { font-family: var(--font-sans); font-size: 0.74rem; letter-spacing: 0.12em; text-transform: uppercase; margin: 0 0 6px; color: var(--muted); }
.callout p:last-child, .callout ul:last-child { margin-bottom: 0; }
.callout.why { border-left: 4px solid var(--gold); }
.callout.tip { border-left: 4px solid var(--accent-2); }
.callout.try { border-left: 4px solid var(--green); }

figure.fig { margin: 22px 0 26px; max-width: 78ch; }
figure.fig figcaption { font-size: 0.9rem; color: var(--muted); margin-top: 8px; padding-left: 4px; }
figure.fig figcaption strong { color: var(--text); }

.toolkit { background: linear-gradient(135deg, var(--surface), var(--surface-2)); border: 1px solid var(--line); border-radius: var(--radius); padding: 18px 22px; margin: 26px 0; max-width: 78ch; }
.toolkit h3 { margin: 0 0 8px; }
.toolkit ol { margin: 0; padding-left: 1.3em; }
.toolkit li { margin-bottom: 8px; }
.exercise { border: 2px dashed color-mix(in srgb, var(--gold) 70%, var(--line)); background: var(--gold-soft); border-radius: var(--radius); padding: 18px 22px; margin: 26px 0; max-width: 78ch; }
.exercise h3 { margin: 0 0 8px; display: flex; gap: 8px; align-items: center; }
.exercise p:last-child { margin-bottom: 0; }

.lesson-nav { display: flex; justify-content: space-between; gap: 12px; margin-top: 44px; padding-top: 22px; border-top: 1px solid var(--line); flex-wrap: wrap; }
.lesson-nav .btn { max-width: 48%; }
.lesson-nav .btn span { overflow: hidden; text-overflow: ellipsis; white-space: nowrap; }
.complete-row { display: flex; align-items: center; gap: 12px; margin-top: 30px; flex-wrap: wrap; }
.complete-row .btn.done { border-color: var(--green); color: var(--green); }

/* ==========================================================================
   Excerpt card
   ========================================================================== */
.excerpt { margin: 34px 0 40px; }
.ex-head { margin-bottom: 12px; }
.ex-head .eyebrow { color: var(--accent); }
.ex-title { font-size: 1.55rem; margin: 4px 0 2px; }
.ex-meta { color: var(--muted); font-size: 0.95rem; }
.ex-meta .sep { margin: 0 6px; opacity: 0.5; }
.ex-why { background: var(--surface-2); border-left: 4px solid var(--gold); padding: 12px 18px; border-radius: 0 12px 12px 0; margin: 14px 0 18px; max-width: 78ch; }
.ex-why h4 { font-family: var(--font-sans); font-size: 0.74rem; letter-spacing: 0.12em; text-transform: uppercase; color: var(--gold); margin: 0 0 6px; }
.ex-why p:last-child { margin-bottom: 0; }
.ex-note { font-size: 0.84rem; color: var(--muted); margin-top: 8px; }

.listen { margin-top: 18px; }
.listen h4 { font-family: var(--font-sans); font-size: 0.74rem; letter-spacing: 0.12em; text-transform: uppercase; color: var(--muted); margin: 0 0 10px; }
.listen ol { list-style: none; padding: 0; margin: 0; display: grid; gap: 8px; }
.listen li { display: grid; grid-template-columns: auto 1fr; gap: 12px; align-items: start; padding: 10px 12px; background: var(--surface); border: 1px solid var(--line); border-radius: 12px; }
.listen li p { margin: 0; font-size: 0.93rem; }
.listen li p strong { display: block; margin-bottom: 2px; }
.seek-btn { display: inline-flex; align-items: center; gap: 6px; padding: 5px 11px 5px 8px; border-radius: 999px; border: 1px solid var(--line); background: var(--surface-2); cursor: pointer; font-size: 0.82rem; font-weight: 600; white-space: nowrap; color: var(--accent); }
.seek-btn:hover { border-color: var(--accent); background: var(--accent-soft); }
.seek-btn .ico { width: 12px; height: 12px; fill: currentColor; }

.ex-actions { display: flex; gap: 10px; flex-wrap: wrap; margin-top: 14px; align-items: center; }
details.abc-src { width: 100%; margin-top: 4px; }
details.abc-src summary { cursor: pointer; font-size: 0.86rem; color: var(--muted); }
details.abc-src pre { margin-top: 8px; font-size: 12.5px; max-height: 320px; }

.technique { margin-top: 16px; max-width: 78ch; }
.technique h4 { font-family: var(--font-sans); font-size: 0.74rem; letter-spacing: 0.12em; text-transform: uppercase; color: var(--muted); margin: 0 0 8px; }
.technique ul { margin: 0; }

/* ==========================================================================
   Score player
   ========================================================================== */
.sp { background: var(--surface); border: 1px solid var(--line); border-radius: var(--radius); box-shadow: var(--shadow); overflow: hidden; outline: none; }
.sp:focus-visible { box-shadow: var(--shadow), 0 0 0 3px color-mix(in srgb, var(--accent) 35%, transparent); }
.sp-sheetwrap { background: var(--sheet); color: var(--sheet-ink); max-height: 64vh; overflow: auto; padding: 8px 10px 4px; }
.sp-compact .sp-sheetwrap { max-height: none; padding: 6px 8px 0; }
.sp-sheet svg { width: 100%; height: auto; display: block; }
.sp-sheet .abcjs-title, .sp-sheet .abcjs-composer, .sp-sheet .abcjs-rhythm { display: none; }
.sp-sheet .abcjs-note, .sp-sheet .abcjs-rest { cursor: pointer; }
.sp-sheet svg .mt-hl, .sp-sheet svg .mt-hl * { fill: var(--hl) !important; }
.sp-sheet svg .mt-hl [stroke] { stroke: var(--hl) !important; }
.sp-sheet svg .mt-cursor { stroke: var(--hl); stroke-width: 2.2; opacity: 0.55; stroke-linecap: round; }
.sp-error { color: var(--accent); padding: 12px; font-size: 0.9rem; }

.sp-kbrow { display: flex; align-items: stretch; background: var(--surface-2); border-top: 1px solid var(--line); }
.sp-kb { flex: 1 1 auto; min-width: 0; padding: 8px 12px 3px; }
.sp-chordbox { flex: 0 0 auto; width: 150px; padding: 8px 12px 6px; border-right: 1px solid var(--line); display: flex; flex-direction: column; justify-content: center; gap: 1px; min-width: 0; }
.sp-chordbox[hidden] { display: none; }
.sp-chordbox-lbl { font-size: 0.64rem; letter-spacing: 0.12em; text-transform: uppercase; color: var(--muted); font-weight: 600; }
.sp-chord-name { font-family: var(--font-serif); font-size: 1.55rem; line-height: 1.15; color: var(--chord-ink); overflow: hidden; text-overflow: ellipsis; white-space: nowrap; }
.sp-chord-notes { font-size: 0.8rem; color: var(--text); letter-spacing: 0.02em; min-height: 1.2em; }
.sp-chord-comment { font-size: 0.74rem; color: var(--muted); font-style: italic; }
.sp-chord-comment:empty { display: none; }
.sp-legend { display: flex; align-items: center; gap: 4px; font-size: 0.66rem; color: var(--muted); margin-top: 4px; white-space: nowrap; }
.sp-legend .sw { display: inline-block; width: 9px; height: 9px; border-radius: 2px; margin-right: 2px; }
.sp-legend .sw-on { background: var(--kb-on); }
.sp-legend .sw-chord { background: var(--kb-chord-black); margin-left: 6px; }

.sp-chords { position: relative; border-top: 1px solid var(--line); background: var(--surface); padding: 6px 10px; overflow-x: auto; overflow-y: hidden; scrollbar-width: thin; }
.sp-chords[hidden] { display: none; }
.sp-chords-scroll { display: flex; gap: 5px; align-items: flex-end; width: max-content; min-width: 100%; }
.sp-chip { position: relative; border: 1px solid var(--line); background: var(--surface-2); border-radius: 8px; padding: 13px 9px 5px; font-size: 0.84rem; font-weight: 600; line-height: 1; cursor: pointer; color: var(--text); white-space: nowrap; transition: background 0.12s, border-color 0.12s, color 0.12s; }
.sp-chip:hover { border-color: var(--chord); }
.sp-chip.bar-start { margin-left: 6px; }
.sp-chip.bar-start:first-child { margin-left: 0; }
.sp-chip .sp-chip-bar { position: absolute; top: 2px; left: 5px; font-size: 0.56rem; font-weight: 500; color: var(--muted); font-variant-numeric: tabular-nums; }
.sp-chip.none { font-weight: 500; font-style: italic; color: var(--muted); }
.sp-chip.cur { background: var(--chord); border-color: var(--chord); color: #fff; }
.sp-chip.cur .sp-chip-bar { color: rgba(255, 255, 255, 0.8); }
.kb { width: 100%; height: auto; max-height: 96px; display: block; }
.kb-white { fill: var(--kb-white); stroke: var(--kb-white-line); stroke-width: 0.5; transition: fill 0.05s; }
.kb-black { fill: var(--kb-black); }
.kb-white.chord { fill: var(--kb-chord); stroke: var(--kb-chord-line); stroke-width: 0.9; }
.kb-black.chord { fill: var(--kb-chord-black); }
.kb-white.on { fill: var(--kb-on); }
.kb-black.on { fill: var(--kb-on-black); }
.kb-label { font-family: var(--font-sans); font-size: 4.1px; fill: #8c8578; text-anchor: middle; pointer-events: none; }
.kb-interactive rect { cursor: pointer; }
.kb-interactive .kb-white:hover { fill: color-mix(in srgb, var(--kb-white) 80%, var(--kb-on)); }

.sp-controls { display: flex; align-items: center; gap: 10px; padding: 10px 12px; border-top: 1px solid var(--line); flex-wrap: wrap; }
.sp-btn { display: inline-grid; place-items: center; width: 38px; height: 38px; border-radius: 50%; border: 1px solid var(--line); background: var(--surface-2); cursor: pointer; color: var(--text); flex: none; }
.sp-btn:hover { border-color: var(--muted); }
.sp-btn .ico { width: 18px; height: 18px; fill: currentColor; }
.sp-play { width: 46px; height: 46px; background: var(--accent); border-color: var(--accent); color: #fff; }
.sp-play:hover { filter: brightness(1.07); border-color: var(--accent); }
.sp-play .ico-pause { display: none; }
.sp.playing .sp-play .ico-play { display: none; }
.sp.playing .sp-play .ico-pause { display: block; }
.sp-loop[aria-pressed="true"] { color: var(--accent); border-color: var(--accent); background: var(--accent-soft); }
.sp-progress { flex: 1 1 160px; position: relative; height: 30px; display: flex; align-items: center; }
.sp-range { width: 100%; margin: 0; appearance: none; -webkit-appearance: none; background: transparent; height: 22px; cursor: pointer; }
.sp-range::-webkit-slider-runnable-track { height: 6px; border-radius: 3px; background: var(--line); }
.sp-range::-moz-range-track { height: 6px; border-radius: 3px; background: var(--line); }
.sp-range::-webkit-slider-thumb { -webkit-appearance: none; width: 16px; height: 16px; border-radius: 50%; background: var(--accent); border: 2px solid var(--surface); margin-top: -5px; box-shadow: 0 1px 3px rgba(0, 0, 0, 0.3); }
.sp-range::-moz-range-thumb { width: 12px; height: 12px; border-radius: 50%; background: var(--accent); border: 2px solid var(--surface); }
.sp-ticks { position: absolute; left: 0; right: 0; top: 21px; height: 5px; pointer-events: none; }
.sp-tick { position: absolute; width: 1px; height: 5px; background: var(--muted); opacity: 0.55; }
.sp-time { font-variant-numeric: tabular-nums; font-size: 0.8rem; color: var(--muted); display: flex; flex-direction: column; line-height: 1.25; min-width: 82px; }
.sp-time .sp-bar { color: var(--text); font-weight: 600; }
.sp-tempo { display: flex; align-items: center; gap: 6px; font-size: 0.78rem; color: var(--muted); }
.sp-tempo-val { min-width: 36px; text-align: right; font-variant-numeric: tabular-nums; }
.sp-tempo-range { width: 86px; accent-color: var(--accent); }
.sp-compact .sp-controls { padding: 6px 10px; gap: 8px; }
.sp-compact .sp-btn { width: 32px; height: 32px; }
.sp-compact .sp-play { width: 36px; height: 36px; }
.sp-compact .sp-tempo, .sp-compact .sp-loop { display: none; }
.sp-compact .sp-time { min-width: 0; }
.sp-compact .sp-time .sp-bar { display: none; }

/* ==========================================================================
   Labs (interactive keyboard)
   ========================================================================== */
.lab { border: 1px solid var(--line); border-radius: var(--radius); padding: 14px 16px; background: var(--surface); margin: 20px 0 26px; max-width: 78ch; box-shadow: var(--shadow); }
.lab .eyebrow { display: block; margin-bottom: 8px; }
.lab-kb .kb { max-height: 130px; }
.lab-readout { font-family: var(--font-serif); font-size: 1.35rem; min-height: 2.2em; padding: 10px 2px 4px; }
.lab-readout small { display: block; font-family: var(--font-sans); font-size: 0.85rem; color: var(--muted); }
.lab-actions { display: flex; gap: 8px; flex-wrap: wrap; }
.lab-actions .btn { background: var(--surface-2); }

/* ==========================================================================
   Reference
   ========================================================================== */
.ref-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(390px, 1fr)); gap: 18px; }
.ref-card { background: var(--surface); border: 1px solid var(--line); border-radius: var(--radius); padding: 16px 18px; }
.ref-card h3 { margin-top: 0; }
.ref-card table { font-size: 0.9rem; margin: 0; }
.ref-card td, .ref-card th { padding: 6px 8px; }
.ref-card .toc { list-style: none; padding: 0; margin: 0; columns: 2; }
.ref-card .toc a { text-decoration: none; }

@media (max-width: 640px) {
  .sp-tempo { display: none; }
  .sp-kbrow { flex-direction: column; }
  .sp-chordbox { width: auto; border-right: 0; border-bottom: 1px solid var(--line); flex-direction: row; align-items: baseline; flex-wrap: wrap; gap: 4px 10px; padding: 6px 12px; }
  .sp-chordbox-lbl { width: 100%; }
  .sp-legend { margin-top: 0; margin-left: auto; }
  .listen li { grid-template-columns: 1fr; }
  h2 { font-size: 1.4rem; }
}
@media print {
  .sidebar, .topbar, .sp-controls, .sp-kbrow, .sp-chords, .ex-actions, .lesson-nav, .complete-row { display: none !important; }
  .app { display: block; }
}