/* ==========================================================================
   Rextune — design system
   Palette drawn from the instrument: rosewood back, spruce top, brass
   machines, tortoiseshell pick, bronze strings. Dark like a music room.
   ========================================================================== */

:root {
  --rosewood: #241610;
  --rosewood-raised: #2e1d14;
  --rosewood-card: #34221735;
  --card: #2b1a11;
  --spruce: #f2e6ca;
  --spruce-dim: #cbb996;
  --spruce-faint: #94825f;
  --amber: #e09b3d;
  --amber-deep: #b5722a;
  --amber-glow: rgba(224, 155, 61, 0.28);
  --tortoise: #9c4f2c;
  --sage: #8fb573;
  --sage-glow: rgba(143, 181, 115, 0.3);
  --bronze: #a89467;
  --line: rgba(203, 172, 118, 0.16);
  --line-strong: rgba(203, 172, 118, 0.32);
  --danger: #c96f4a;

  --font-display: "Fraunces", "Georgia", serif;
  --font-body: "Karla", "Helvetica Neue", sans-serif;
  --font-mono: "Space Mono", "SFMono-Regular", monospace;

  --radius: 14px;
  --radius-sm: 9px;
  --nav-h: 66px;
}

* { box-sizing: border-box; }

html, body {
  margin: 0;
  padding: 0;
  background: var(--rosewood);
  color: var(--spruce);
  font-family: var(--font-body);
  font-size: 16px;
  line-height: 1.55;
  -webkit-font-smoothing: antialiased;
  overscroll-behavior-y: none;
}

body {
  min-height: 100dvh;
  /* faint wood-grain wash */
  background:
    radial-gradient(120% 60% at 50% -10%, #33201335 0%, transparent 60%),
    var(--rosewood);
}

/* ------------------------------------------------------------------ shell */

.shell {
  max-width: 640px;
  margin: 0 auto;
  padding: 20px
    max(20px, env(safe-area-inset-right, 0px))
    calc(var(--nav-h) + 28px + env(safe-area-inset-bottom, 0px))
    max(20px, env(safe-area-inset-left, 0px));
}

header.masthead {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  padding: 6px 2px 14px;
}

.wordmark {
  font-family: var(--font-display);
  font-weight: 600;
  font-size: 26px;
  letter-spacing: 0.01em;
  color: var(--spruce);
  text-decoration: none;
}
.wordmark .x { color: var(--amber); }

.masthead .session {
  font-family: var(--font-mono);
  font-size: 11px;
  color: var(--spruce-faint);
  letter-spacing: 0.06em;
  text-transform: uppercase;
}

/* six-string divider: gauges go thick -> thin, like the real thing */
.strings-rule {
  height: 23px;
  margin: 2px 0 18px;
  background:
    linear-gradient(var(--line-strong), var(--line-strong)) 0 1px / 100% 3px no-repeat,
    linear-gradient(var(--line-strong), var(--line-strong)) 0 6px / 100% 2.5px no-repeat,
    linear-gradient(var(--line), var(--line)) 0 10.5px / 100% 2px no-repeat,
    linear-gradient(var(--line), var(--line)) 0 14.5px / 100% 1.5px no-repeat,
    linear-gradient(var(--line), var(--line)) 0 18px / 100% 1px no-repeat,
    linear-gradient(var(--line), var(--line)) 0 21px / 100% 1px no-repeat;
}

main { display: block; }
section.view { display: none; }
section.view.active { display: block; animation: viewin 260ms ease; }

@keyframes viewin {
  from { opacity: 0; transform: translateY(6px); }
  to { opacity: 1; transform: none; }
}

h1, h2, h3 { font-family: var(--font-display); font-weight: 600; margin: 0; }

.view > .view-title {
  font-size: 30px;
  letter-spacing: 0.005em;
  margin-bottom: 4px;
}
.view > .view-sub {
  color: var(--spruce-dim);
  margin: 0 0 22px;
  max-width: 46ch;
}

/* ------------------------------------------------------------------ cards */

.card {
  background: linear-gradient(180deg, var(--rosewood-raised), var(--card));
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 18px;
}

button {
  font-family: inherit;
  cursor: pointer;
}

.btn {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  border: 1px solid var(--amber-deep);
  background: linear-gradient(180deg, var(--amber), var(--amber-deep));
  color: #241407;
  font-family: var(--font-body);
  font-weight: 700;
  font-size: 16px;
  border-radius: 999px;
  padding: 13px 26px;
  transition: transform 120ms ease, box-shadow 120ms ease;
}
.btn:hover { box-shadow: 0 4px 22px var(--amber-glow); }
.btn:active { transform: scale(0.98); }

.btn-quiet {
  background: none;
  border: 1px solid var(--line-strong);
  color: var(--spruce-dim);
  font-weight: 600;
  border-radius: 999px;
  padding: 8px 16px;
  font-size: 14px;
}
.btn-quiet:hover { color: var(--spruce); border-color: var(--bronze); }
.btn-quiet[aria-pressed="true"] {
  color: var(--amber);
  border-color: var(--amber-deep);
}

:is(button, a, [tabindex]):focus-visible {
  outline: 2px solid var(--amber);
  outline-offset: 3px;
  border-radius: 6px;
}

/* ------------------------------------------------------------------ tuner */

.tuner-stage { text-align: center; }

.tuner-note-row {
  display: flex;
  align-items: baseline;
  justify-content: center;
  gap: 14px;
  min-height: 96px;
}

.tuner-note {
  font-family: var(--font-display);
  font-size: 84px;
  font-weight: 600;
  line-height: 1;
  color: var(--spruce);
  transition: color 200ms ease;
}
.tuner-note.intune { color: var(--sage); }
.tuner-note .oct { font-size: 30px; color: var(--spruce-faint); font-family: var(--font-mono); }

.tuner-hz {
  font-family: var(--font-mono);
  font-size: 14px;
  color: var(--spruce-faint);
  min-height: 20px;
  letter-spacing: 0.04em;
}

.tuner-hint {
  min-height: 24px;
  margin-top: 6px;
  color: var(--spruce-dim);
  font-size: 15px;
}
.tuner-hint.intune { color: var(--sage); font-weight: 700; }

/* the fretboard meter — Rextune's signature */
.meter {
  position: relative;
  height: 96px;
  margin: 18px 0 4px;
}

.meter svg { width: 100%; height: 100%; display: block; }

.meter .string-line { stroke: var(--bronze); stroke-width: 2; opacity: 0.75; transition: stroke 250ms ease, opacity 250ms ease; }
.meter.intune .string-line { stroke: var(--sage); opacity: 1; }

.meter .fret-tick { stroke: var(--line-strong); stroke-width: 2; }
.meter .fret-label { fill: var(--spruce-faint); font-family: var(--font-mono); font-size: 9px; }

.meter .inlay { fill: var(--spruce-dim); opacity: 0.8; transition: fill 250ms ease, opacity 250ms ease; }
.meter.intune .inlay { fill: var(--sage); opacity: 1; }

.meter .capo {
  fill: var(--amber);
  stroke: var(--amber-deep);
  stroke-width: 1.5;
  transition: fill 250ms ease;
}
.meter.intune .capo { fill: var(--sage); stroke: #6d9154; }
.meter .capo-shadow { fill: rgba(0, 0, 0, 0.35); }

.meter .idle-note {
  fill: var(--spruce-faint);
  font-family: var(--font-body);
  font-size: 13px;
}

/* headstock string selector */
.headstock {
  margin: 26px auto 0;
  max-width: 330px;
}
.headstock svg { width: 100%; display: block; }
.headstock .plate {
  fill: var(--rosewood-raised);
  stroke: var(--line-strong);
  stroke-width: 1.5;
}
.headstock .post { stroke: var(--bronze); stroke-width: 2.5; opacity: .8; }

.peg { cursor: pointer; }
.peg circle.button {
  fill: var(--card);
  stroke: var(--bronze);
  stroke-width: 1.5;
  transition: fill 150ms ease, stroke 150ms ease;
}
.peg text {
  fill: var(--spruce-dim);
  font-family: var(--font-mono);
  font-weight: 700;
  font-size: 15px;
  text-anchor: middle;
  dominant-baseline: central;
  pointer-events: none;
  transition: fill 150ms ease;
}
.peg:hover circle.button { stroke: var(--amber); }
.peg.target circle.button { fill: var(--amber); stroke: var(--amber-deep); }
.peg.target text { fill: #241407; }
.peg.heard circle.button { stroke: var(--amber); stroke-width: 3; }
.peg.tuned circle.button { fill: var(--sage); stroke: #6d9154; }
.peg.tuned text { fill: #1c2413; }

.tuner-modes {
  display: flex;
  justify-content: center;
  gap: 10px;
  margin-top: 18px;
}

.tuner-start {
  padding: 44px 10px 40px;
  text-align: center;
}
.tuner-start p {
  color: var(--spruce-dim);
  max-width: 40ch;
  margin: 14px auto 0;
}
.tuner-error { color: var(--danger); font-size: 14px; margin-top: 12px; }

/* ------------------------------------------------------------------ learn */

.level {
  margin-bottom: 14px;
  overflow: hidden;
}

.level-head {
  display: flex;
  width: 100%;
  align-items: center;
  gap: 16px;
  background: none;
  border: 0;
  color: inherit;
  text-align: left;
  padding: 2px;
}

.level-num {
  font-family: var(--font-mono);
  font-size: 13px;
  color: var(--amber);
  border: 1px solid var(--amber-deep);
  border-radius: 999px;
  width: 34px;
  height: 34px;
  flex: 0 0 34px;
  display: grid;
  place-items: center;
}
.level.soon .level-num { color: var(--spruce-faint); border-color: var(--line-strong); }

.level-title { font-size: 20px; }
.level-sub { color: var(--spruce-dim); font-size: 14px; margin-top: 1px; }

.level-meta {
  margin-left: auto;
  font-family: var(--font-mono);
  font-size: 11px;
  color: var(--spruce-faint);
  text-transform: uppercase;
  letter-spacing: 0.08em;
  white-space: nowrap;
}

.level-body { display: none; padding-top: 14px; }
.level.open .level-body { display: block; }

.lesson-link {
  display: flex;
  width: 100%;
  align-items: center;
  gap: 10px;
  background: none;
  border: 0;
  border-top: 1px solid var(--line);
  color: var(--spruce);
  font-size: 16px;
  text-align: left;
  padding: 12px 2px;
}
.lesson-link:hover { color: var(--amber); }
.lesson-link .go { margin-left: auto; color: var(--spruce-faint); }

/* lesson detail */
.lesson-back { margin-bottom: 16px; }
.lesson-intro { color: var(--spruce-dim); max-width: 52ch; }

.step {
  display: flex;
  gap: 14px;
  padding: 16px 0;
  border-bottom: 1px solid var(--line);
}
.step:last-child { border-bottom: 0; }
.step-num {
  font-family: var(--font-mono);
  color: var(--amber);
  font-size: 13px;
  padding-top: 3px;
  flex: 0 0 20px;
}
.step h3 { font-size: 17px; margin-bottom: 4px; font-family: var(--font-body); font-weight: 700; }
.step p { margin: 0; color: var(--spruce-dim); }

/* ----------------------------------------------------------------- chords */

.chord-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(140px, 1fr));
  gap: 12px;
}

.chord-cell {
  background: linear-gradient(180deg, var(--rosewood-raised), var(--card));
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 12px 8px 10px;
  color: inherit;
  text-align: center;
  transition: border-color 150ms ease, transform 150ms ease;
}
.chord-cell:hover { border-color: var(--amber-deep); transform: translateY(-2px); }
.chord-cell .sym { font-family: var(--font-display); font-size: 22px; }
.chord-cell .nm { color: var(--spruce-faint); font-size: 12px; margin-top: 1px; }
.chord-cell svg { margin-top: 8px; }

.chord-detail .chord-head {
  display: flex;
  align-items: baseline;
  gap: 12px;
  margin-bottom: 4px;
}
.chord-detail .chord-head h2 { font-size: 40px; }
.chord-detail .chord-head .nm { color: var(--spruce-dim); }

.chord-detail-diagram { max-width: 300px; margin: 10px auto; }

.chord-notes { display: grid; gap: 10px; margin-top: 14px; }
.chord-note {
  display: flex;
  gap: 12px;
  align-items: baseline;
}
.chord-note .k {
  font-family: var(--font-mono);
  font-size: 10px;
  letter-spacing: 0.09em;
  text-transform: uppercase;
  color: var(--amber);
  flex: 0 0 74px;
  padding-top: 2px;
}
.chord-note p { margin: 0; color: var(--spruce-dim); }

/* chord diagram svg */
.diagram .grid-line { stroke: var(--line-strong); stroke-width: 1.5; }
.diagram .nut { stroke: var(--spruce-dim); stroke-width: 5; stroke-linecap: round; }
.diagram .dot { fill: var(--amber); }
.diagram .dot-num {
  fill: #241407;
  font-family: var(--font-mono);
  font-weight: 700;
  font-size: 13px;
  text-anchor: middle;
  dominant-baseline: central;
}
.diagram .open-mark { stroke: var(--sage); stroke-width: 1.8; fill: none; }
.diagram .mute-mark { stroke: var(--spruce-faint); stroke-width: 1.8; }
.diagram .string-name {
  fill: var(--spruce-faint);
  font-family: var(--font-mono);
  font-size: 10px;
  text-anchor: middle;
}

/* ----------------------------------------------------------------- guitar */

.guitar-wrap {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 16px;
}
@media (min-width: 560px) {
  .guitar-wrap { grid-template-columns: 300px minmax(0, 1fr); align-items: start; }
  .part-card { position: sticky; top: 16px; }
}

.guitar-fig svg { width: 100%; max-width: 320px; display: block; margin: 0 auto; }

.gtr .wood { fill: #3a2718; stroke: var(--bronze); stroke-width: 1.6; }
.gtr .top { fill: #402c1a; }
.gtr .board { fill: #17100b; stroke: #000; stroke-width: 0.6; }
.gtr .fretwire { stroke: var(--bronze); stroke-width: 1.4; opacity: 0.85; }
.gtr .inlaydot { fill: var(--spruce-dim); opacity: 0.7; }
.gtr .gstring { stroke: var(--bronze); stroke-width: 0.9; opacity: 0.85; }
.gtr .rosette { fill: none; stroke: var(--amber-deep); stroke-width: 3; opacity: 0.7; }
.gtr .hole { fill: #120b07; }
.gtr .guard { fill: #1d120b; stroke: var(--tortoise); stroke-width: 1; opacity: 0.9; }
.gtr .bridgewood { fill: #17100b; stroke: #000; stroke-width: 0.6; }
.gtr .saddleline { stroke: var(--spruce); stroke-width: 2.4; opacity: 0.9; }
.gtr .pin { fill: var(--spruce-dim); }
.gtr .peghead { fill: var(--bronze); }

.hotspot { cursor: pointer; outline: none; }
.hotspot:focus-visible circle { stroke: var(--spruce); stroke-width: 2.5; }
.hotspot circle {
  fill: rgba(224, 155, 61, 0.14);
  stroke: var(--amber);
  stroke-width: 1.5;
  transition: fill 150ms ease;
}
.hotspot:hover circle { fill: rgba(224, 155, 61, 0.35); }
.hotspot.sel circle { fill: var(--amber); }
.hotspot text {
  fill: var(--amber);
  font-family: var(--font-mono);
  font-size: 11px;
  font-weight: 700;
  text-anchor: middle;
  dominant-baseline: central;
  pointer-events: none;
}
.hotspot.sel text { fill: #241407; }

.part-card h3 { font-size: 20px; margin-bottom: 6px; }
.part-card p { margin: 0; color: var(--spruce-dim); }
.part-card .placeholder { color: var(--spruce-faint); }

.part-list { display: flex; flex-wrap: wrap; gap: 8px; margin-top: 14px; }
.part-chip {
  border: 1px solid var(--line-strong);
  background: none;
  color: var(--spruce-dim);
  border-radius: 999px;
  font-size: 13px;
  padding: 6px 12px;
}
.part-chip:hover { color: var(--spruce); border-color: var(--bronze); }
.part-chip.sel { color: #241407; background: var(--amber); border-color: var(--amber-deep); font-weight: 700; }

/* ------------------------------------------------------------------- nav */

nav.tabs {
  position: fixed;
  bottom: 0;
  left: 0;
  right: 0;
  height: calc(var(--nav-h) + env(safe-area-inset-bottom, 0px));
  padding-bottom: env(safe-area-inset-bottom, 0px);
  background: rgba(26, 15, 9, 0.92);
  -webkit-backdrop-filter: blur(14px);
  backdrop-filter: blur(14px);
  border-top: 1px solid var(--line);
  display: flex;
  justify-content: center;
  z-index: 40;
}

nav.tabs .inner {
  display: flex;
  width: 100%;
  max-width: 640px;
}

.tab {
  flex: 1;
  background: none;
  border: 0;
  color: var(--spruce-faint);
  font-family: var(--font-body);
  font-size: 12px;
  font-weight: 600;
  letter-spacing: 0.04em;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 3px;
  padding-top: 9px;
}
.tab svg { width: 24px; height: 24px; stroke: currentColor; fill: none; stroke-width: 1.7; stroke-linecap: round; stroke-linejoin: round; }
.tab[aria-current="true"] { color: var(--amber); }

footer.colophon {
  text-align: center;
  color: var(--spruce-faint);
  font-size: 12.5px;
  padding: 34px 0 8px;
}
footer.colophon .mono { font-family: var(--font-mono); font-size: 11px; letter-spacing: 0.05em; }

@media (prefers-reduced-motion: reduce) {
  * { animation: none !important; transition-duration: 0.01ms !important; }
}