/* ---------- Tokens (dark only) ---------- */
:root {
  color-scheme: dark;
  font-family: "Helvetica Neue", Helvetica, Arial, sans-serif;
  line-height: 1.4;

  --bg: #0f1115;
  --surface: #1a1d23;
  --surface-soft: #232730;
  --text: #ececec;
  --muted: #9aa3b2;
  --border: #353a45;
  --border-strong: #ececec;
  --track: #2a2f39;
  --radius: 10px;
  --radius-lg: 14px;
  --shadow: 0 1px 2px rgba(0, 0, 0, 0.4), 0 1px 3px rgba(0, 0, 0, 0.5);

  /* Palette mirrors the circle-of-fifths arrangement; hue rotates around
   * the wheel so neighbouring degrees have neighbouring colours. */
  --degree-0:  #4d6dff;  /* Do  (1)  blue        */
  --degree-1:  #d4ec3a;  /* Ra  (b2) lime        */
  --degree-2:  #ec3fc7;  /* Re  (2)  magenta     */
  --degree-3:  #3ddc7d;  /* Me  (b3) green       */
  --degree-4:  #ff5757;  /* Mi  (3)  red         */
  --degree-5:  #4ea0ff;  /* Fa  (4)  light blue  */
  --degree-6:  #f5e23a;  /* Fi  (#4) yellow      */
  --degree-7:  #a855f7;  /* Sol (5)  purple      */
  --degree-8:  #6ee862;  /* Le  (b6) light green */
  --degree-9:  #ff5c9c;  /* La  (6)  pink        */
  --degree-10: #2dd4e2;  /* Te  (b7) cyan        */
  --degree-11: #f59e0b;  /* Ti  (7)  orange      */

  /* Site accent matches Do. */
  --accent: var(--degree-0);
  accent-color: var(--accent);
}
html { scrollbar-color: var(--accent) var(--surface-soft); }
/* ---------- Base ---------- */
* { box-sizing: border-box; }
body { margin: 0; background: var(--bg); color: var(--text); }
main {
  max-width: 640px;
  margin: 1rem auto;
  padding: 0 0.9rem 2rem;
  display: grid;
  gap: 1rem;
}
h1 {
  font-size: 1.25rem;
  margin: 0;
  letter-spacing: 0.01em;
}
.app-header {
  display: flex;
  align-items: center;
  justify-content: center;
  position: relative;
  margin-top: 0.25rem;
}
.icon-btn {
  position: absolute;
  right: 0;
  width: 2.1rem;
  height: 2.1rem;
  padding: 0;
  border-radius: 50%;
  display: inline-flex;
  align-items: center;
  justify-content: center;
}
.intro {
  margin: -0.25rem 0 0;
  text-align: center;
  max-width: 38rem;
  align-self: center;
  line-height: 1.5;
}
.intro span[aria-hidden] { font-weight: 700; color: var(--text); }
.intro .hint, .hint {
  display: inline-block;
  margin-top: 0.35rem;
  font-size: 0.78rem;
  color: var(--muted);
}
.degrees-hint {
  margin: 0.25rem 0 0;
  text-align: center;
  font-style: italic;
}

/* Inline SVG icons (Lucide, ISC license) inside buttons. */
.icon { width: 1.05rem; height: 1.05rem; flex: none; stroke: currentColor; }
.icon-btn .icon { width: 1.15rem; height: 1.15rem; }
.icon-text { display: inline-flex; align-items: center; gap: 0.4rem; }

/* ---------- Form controls ---------- */
input, select, button { font: inherit; color: inherit; }
input[type="number"], select {
  padding: 0.32rem 0.48rem;
  border: 1px solid var(--border);
  border-radius: var(--radius);
  background: var(--surface);
}
input[type="number"] { width: 4.2rem; }
button {
  border: 1px solid var(--border);
  background: var(--surface);
  border-radius: 999px;
  padding: 0.36rem 0.85rem;
  font-weight: 600;
  cursor: pointer;
  transition: background 120ms;
}
button:hover:not(:disabled) { background: var(--surface-soft); }
button:disabled { opacity: 0.45; cursor: not-allowed; }
button.primary {
  background: var(--text);
  color: var(--bg);
  border-color: var(--text);
}
button.primary:hover:not(:disabled) { filter: brightness(1.15); }
button:focus-visible,
input:focus-visible,
select:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: 2px;
}
label { font-weight: 600; font-size: 0.85rem; }
.muted { color: var(--muted); font-size: 0.78rem; }

/* ---------- Card / section ---------- */
.card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow);
  padding: 0.9rem 1rem;
  display: grid;
  gap: 0.85rem;
}
.card h2 {
  font-size: 0.78rem;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--muted);
  margin: 0;
  font-weight: 700;
}
.row {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 0.5rem 1rem;
}
.row.center { justify-content: center; }
.field { display: inline-flex; align-items: center; gap: 0.4rem; }
.field-stack { display: grid; gap: 0.5rem; }
.field-stack .field-row { display: flex; align-items: center; gap: 0.55rem; }
.field-stack input[type="range"] { flex: 1; min-width: 0; accent-color: var(--accent); }
.field-stack .value { min-width: 3.2rem; text-align: right; font-variant-numeric: tabular-nums; }
.field-stack > .field-row > label:first-child { min-width: 4.5rem; }

/* ---------- Segmented control ----------
 * Used for choosing among a small set of discrete values (tonic, note count).
 */
.segmented {
  display: grid;
  grid-auto-flow: column;
  grid-auto-columns: 1fr;
  gap: 4px;
  background: var(--surface-soft);
  border: 1px solid var(--border);
  border-radius: 999px;
  padding: 3px;
  width: 100%;
}
.segmented button {
  border: none;
  background: transparent;
  border-radius: 999px;
  padding: 0.3rem 0.2rem;
  font-size: 0.78rem;
  font-weight: 600;
  color: var(--muted);
  cursor: pointer;
  min-width: 0;
  transition: background 120ms, color 120ms;
}
.segmented button:hover { color: var(--text); background: var(--surface); }
.segmented button[aria-checked="true"] {
  background: var(--accent);
  color: white;
}
.field-row.stacked { flex-direction: column; align-items: stretch; gap: 0.35rem; }
.field-row.stacked > label { color: var(--muted); font-size: 0.78rem; text-transform: uppercase; letter-spacing: 0.06em; }

/* ---------- Vocal range (dual slider) ----------
 * Layout: thumb labels sit in their own row above the slider track so they
 * are never obscured by the thumbs themselves.
 */
.range {
  display: grid;
  gap: 0.35rem;
}
.range-track {
  position: relative;
  /* Top space (1.4rem) reserved for the thumb labels; bottom space holds
     the slider track + thumbs. */
  height: 2.8rem;
  padding-top: 1.4rem;
  --range-start: 0%;
  --range-end: 100%;
}
.range-track::before {
  content: "";
  position: absolute;
  left: 0;
  right: 0;
  bottom: 50%;
  transform: translateY(50%);
  /* Center the track within the lower half (below the labels). */
  top: auto;
  margin-bottom: -0.7rem;
  height: 4px;
  border-radius: 999px;
  background:
    linear-gradient(to right,
      var(--track) 0%,
      var(--track) var(--range-start),
      var(--accent) var(--range-start),
      var(--accent) var(--range-end),
      var(--track) var(--range-end),
      var(--track) 100%);
}
.range-track input[type="range"] {
  position: absolute;
  left: 0;
  right: 0;
  bottom: 0;
  height: 1.4rem;
  width: 100%;
  margin: 0;
  pointer-events: none;
  -webkit-appearance: none;
  appearance: none;
  background: none;
}
.range-track input[type="range"]::-webkit-slider-thumb,
.range-track input[type="range"]::-moz-range-thumb {
  pointer-events: auto;
  -webkit-appearance: none;
  width: 18px;
  height: 18px;
  border-radius: 50%;
  border: 1.5px solid var(--border-strong);
  background: var(--surface);
  cursor: pointer;
  box-shadow: var(--shadow);
}
.range-thumb-label {
  position: absolute;
  top: 0;
  transform: translateX(-50%);
  font-size: 0.72rem;
  font-weight: 700;
  color: var(--muted);
  background: var(--surface);
  padding: 0 0.2rem;
  border-radius: 4px;
  pointer-events: none;
  white-space: nowrap;
}

/* ---------- Scale degrees ---------- */
.scale {
  display: grid;
  gap: 0.55rem;
  justify-items: center;
}
.scale-presets {
  display: flex;
  flex-wrap: wrap;
  gap: 0.4rem;
  justify-content: center;
}
.scale-presets button {
  padding: 0.22rem 0.6rem;
  font-size: 0.78rem;
}
/* Circle-of-fifths arrangement of scale degrees. Items are absolutely
 * positioned around a square container — a colored dot on the outer ring,
 * with the solfège label nested inward. Click a dot or its label to
 * toggle that degree on/off. */
.degrees {
  position: relative;
  width: min(20rem, 100%);
  aspect-ratio: 1;
  margin: 0.25rem auto;
}
.wheel-credit {
  margin: 0.1rem 0 0;
  text-align: center;
  font-size: 0.72rem;
  font-style: italic;
  color: var(--muted);
}
.wheel-credit a { color: inherit; text-decoration: underline; text-underline-offset: 2px; }
.wheel-credit a:hover { color: var(--text); }
.deg-dot,
.deg-label {
  position: absolute;
  transform: translate(-50%, -50%);
  border: none;
  background: transparent;
  padding: 0;
  cursor: pointer;
  user-select: none;
  touch-action: manipulation;
  -webkit-tap-highlight-color: transparent;
}
.deg-dot {
  width: 18px;
  height: 18px;
  border-radius: 50%;
  border: 1.5px solid currentColor;
  background: transparent;
  transition: background-color 120ms, transform 120ms;
}
.deg-dot[aria-pressed="true"] { background: currentColor; }
.deg-dot:hover:not(:disabled) { transform: translate(-50%, -50%) scale(1.15); background: var(--surface-soft); }
.deg-dot[aria-pressed="true"]:hover { background: currentColor; filter: brightness(1.1); }

/* Visual feedback when a degree is sounding (during melody playback,
 * a tap on a melody note, or a press-and-hold preview). */
.deg-dot.playing,
.deg-dot.flash {
  background: currentColor;
  box-shadow: 0 0 0 4px color-mix(in srgb, currentColor 35%, transparent),
              0 0 14px 2px currentColor;
  transform: translate(-50%, -50%) scale(1.4);
}
.deg-label.playing,
.deg-label.flash {
  opacity: 1;
  text-shadow: 0 0 10px currentColor;
  transform: translate(-50%, -50%) scale(1.15);
}
.deg-dot, .deg-label { transition: transform 120ms ease-out, opacity 120ms, background-color 120ms, box-shadow 160ms; }
.deg-label {
  font-weight: 700;
  font-size: 0.95rem;
  line-height: 1;
  opacity: 0.45;
  transition: opacity 120ms;
}
.deg-label[aria-pressed="true"] { opacity: 1; }
.deg-label:hover { opacity: 0.85; }
.deg-dot:focus-visible,
.deg-label:focus-visible { outline: 2px solid var(--accent); outline-offset: 3px; }

/* ---------- Melody display ---------- */
.melody {
  font-size: 1.45rem;
  font-weight: 700;
  letter-spacing: 0.015em;
  line-height: 1.55;
  min-height: 2.2em;
  text-align: center;
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  padding: 0.9rem 1rem;
  background: var(--surface);
}
.melody .interval, .melody .note { white-space: nowrap; }
.melody.placeholder { font-size: 0.95rem; font-weight: 400; font-style: italic; color: var(--muted); }
.melody .tonic-note { color: var(--degree-0); }
.melody .interval { color: var(--muted); margin: 0 0.05em; font-weight: 500; }
.melody .note {
  display: inline-block;
  padding: 0 0.18em;
  border-radius: 6px;
  cursor: pointer;
  transition: background-color 80ms linear, transform 80ms ease-out;
}
.melody .note:hover { background: var(--surface-soft); }
.melody .note { touch-action: manipulation; }
.melody .note:focus-visible { outline: 2px solid var(--accent); outline-offset: 2px; }
.melody .note.playing {
  background: var(--surface-soft);
  box-shadow: inset 0 -2px 0 currentColor;
  transform: translateY(-1px);
}

/* ---------- Degree colors (shared by checkbox labels & melody output) ---------- */
.deg-do  { color: var(--degree-0); }
.deg-ra  { color: var(--degree-1); }
.deg-re  { color: var(--degree-2); }
.deg-me  { color: var(--degree-3); }
.deg-mi  { color: var(--degree-4); }
.deg-fa  { color: var(--degree-5); }
.deg-fi  { color: var(--degree-6); }
.deg-sol { color: var(--degree-7); }
.deg-le  { color: var(--degree-8); }
.deg-la  { color: var(--degree-9); }
.deg-te  { color: var(--degree-10); }
.deg-ti  { color: var(--degree-11); }

/* ---------- Playback ---------- */
.playback { display: flex; flex-wrap: wrap; gap: 0.5rem; justify-content: center; }
#status { width: 100%; text-align: center; min-height: 1em; }

/* ---------- Mobile ---------- */
@media (max-width: 640px) {
  main { margin: 0.5rem auto; padding: 0 0.6rem 1.2rem; gap: 0.75rem; }
  .card { padding: 0.75rem 0.85rem; gap: 0.7rem; }
  .melody { font-size: 1.2rem; padding: 0.75rem; }
  .row { gap: 0.4rem 0.7rem; }
  .playback button { flex: 1 1 auto; }
}

.site-footer {
  max-width: 40rem;
  margin: 2rem auto 1.5rem;
  padding: 1rem 1.25rem 0;
  border-top: 1px solid var(--border, rgba(127,127,127,0.25));
  text-align: center;
  font-size: 0.78rem;
  color: var(--muted);
}
.site-footer p { margin: 0.35rem 0; }
.site-footer a {
  color: inherit;
  text-decoration: underline;
  text-underline-offset: 2px;
}
.site-footer a:hover,
.site-footer a:focus-visible { color: var(--text); }

.deg-num {
  display: inline-block;
  margin-left: 0.18em;
  font-size: 0.72em;
  font-weight: 500;
  vertical-align: sub;
  opacity: 0.8;
  letter-spacing: 0;
  font-feature-settings: "sups" 0;
}

.gh-link {
  display: inline-flex;
  align-items: center;
  gap: 0.4rem;
  text-decoration: none;
  padding: 0.25rem 0.5rem;
  border-radius: 6px;
}
.gh-link:hover,
.gh-link:focus-visible { color: var(--text); background: var(--surface, rgba(127,127,127,0.08)); }
.gh-link .icon { width: 1.05em; height: 1.05em; }