/* Hollow in a browser: the visualiser's calm white (hollow-card/web), as a
   control surface. One column on a phone, a grid on a desktop. */
:root {
  --mist: #eef3f6;
  --paper: #f7fafb;
  --ink: #1f2a30;
  --ink-2: #4f5d65;
  --ink-3: #7d8a91;
  --line: rgba(31, 42, 48, 0.14);
  --line-strong: rgba(31, 42, 48, 0.32);
  --fill: rgba(31, 42, 48, 0.06);
  --fill-strong: rgba(31, 42, 48, 0.12);
  --surface: rgba(255, 255, 255, 0.62);
  --warm: #b0623a;
  --serif: 'Cormorant Garamond', 'Iowan Old Style', Georgia, serif;
  --sans: 'Karla', 'Avenir Next', 'Segoe UI', system-ui, sans-serif;
  color-scheme: light;
}

* { box-sizing: border-box; }
html { background: var(--mist); }
body {
  margin: 0; min-height: 100vh; color: var(--ink); background: radial-gradient(120% 80% at 50% 0%, var(--paper), var(--mist));
  font: 300 15px/1.5 var(--sans); -webkit-font-smoothing: antialiased;
  padding: max(20px, env(safe-area-inset-top)) max(16px, env(safe-area-inset-right)) max(24px, env(safe-area-inset-bottom)) max(16px, env(safe-area-inset-left));
}
b { font-weight: 400; }
.quiet { color: var(--ink-3); }
.small { font-size: 13px; }
.warn { color: var(--warm); }
[hidden] { display: none !important; }

.top { display: flex; justify-content: space-between; align-items: flex-end; gap: 16px; flex-wrap: wrap; max-width: 1080px; margin: 0 auto 22px; }
h1 { font: 300 14px/1 var(--sans); letter-spacing: 0.34em; color: var(--ink-2); margin: 6px 0 14px; }
.mode-line { margin: 0; font: italic 300 40px/1 var(--serif); }
.mode-line .quiet { font-size: 26px; margin-left: 6px; }
.power { display: flex; align-items: center; gap: 12px; flex-wrap: wrap; }

main { display: grid; gap: 14px; max-width: 1080px; margin: 0 auto; grid-template-columns: repeat(3, minmax(0, 1fr)); }
.panel {
  background: var(--surface); border: 1px solid var(--line); border-radius: 16px; padding: 16px 18px 18px;
  backdrop-filter: blur(6px); -webkit-backdrop-filter: blur(6px); display: grid; gap: 14px; align-content: start;
}
.panel.wide { grid-column: span 3; }
h2 { font: italic 300 24px/1 var(--serif); margin: 0; display: flex; align-items: baseline; justify-content: space-between; }
.hint { font: 300 11px/1 var(--sans); letter-spacing: 0.08em; text-transform: uppercase; color: var(--ink-3); }

.field { display: grid; gap: 8px; }
.label { font-size: 13px; color: var(--ink-2); display: flex; justify-content: space-between; align-items: baseline; gap: 8px; }
.slider { grid-template-columns: 1fr auto; align-items: center; column-gap: 12px; }
.slider .label { grid-column: 1 / -1; }
.slider output { font-size: 13px; color: var(--ink-2); min-width: 6.5em; text-align: right; font-variant-numeric: tabular-nums; }
.slider.inline { display: inline-grid; grid-template-columns: minmax(120px, 220px) auto; }
.row { display: flex; gap: 8px; align-items: center; flex-wrap: wrap; }
.grid2 { display: grid; gap: 12px; grid-template-columns: 1fr 1fr; }
.check { display: flex; gap: 10px; align-items: center; font-size: 13px; color: var(--ink-2); }
.check input { width: 18px; height: 18px; accent-color: var(--ink); }

button {
  font: 300 14px/1 var(--sans); color: var(--ink-2); background: transparent;
  border: 1px solid var(--line); border-radius: 999px; padding: 9px 15px; min-height: 38px; cursor: pointer;
  transition: color 0.2s, border-color 0.2s, background 0.2s; touch-action: manipulation; -webkit-tap-highlight-color: transparent;
}
button:hover { color: var(--ink); border-color: var(--line-strong); }
button[aria-pressed='true'] { color: var(--ink); border-color: var(--line-strong); background: var(--fill-strong); }
button:active { background: var(--fill); }
button.soft { border-style: dashed; }
button.primary { color: var(--ink); border-color: var(--line-strong); padding: 11px 26px; font-size: 15px; letter-spacing: 0.06em; }
button:focus-visible, input:focus-visible, select:focus-visible { outline: 1px solid var(--ink); outline-offset: 3px; }
.choices { display: flex; flex-wrap: wrap; gap: 6px; }

select {
  font: 300 14px/1.2 var(--sans); color: var(--ink); background: rgba(255, 255, 255, 0.7);
  border: 1px solid var(--line); border-radius: 10px; padding: 9px 10px; min-height: 40px; width: 100%;
}

input[type=range] { -webkit-appearance: none; appearance: none; width: 100%; height: 32px; background: transparent; margin: 0; touch-action: pan-y; }
input[type=range]::-webkit-slider-runnable-track { height: 2px; background: var(--line-strong); border-radius: 2px; }
input[type=range]::-moz-range-track { height: 2px; background: var(--line-strong); border-radius: 2px; }
input[type=range]::-webkit-slider-thumb {
  -webkit-appearance: none; width: 22px; height: 22px; margin-top: -10px; border-radius: 50%;
  background: var(--paper); border: 1px solid var(--ink-2); box-shadow: 0 1px 4px rgba(31, 42, 48, 0.15);
}
input[type=range]::-moz-range-thumb { width: 20px; height: 20px; border-radius: 50%; background: var(--paper); border: 1px solid var(--ink-2); }

.keys { display: flex; height: 92px; position: relative; user-select: none; -webkit-user-select: none; }
.key {
  flex: 1; height: 100%; padding: 0; min-height: 0; border-radius: 0 0 8px 8px; background: rgba(255, 255, 255, 0.85);
  border: 1px solid var(--line); margin-left: -1px;
}
.key.black { flex: 0 0 0; width: 0; padding: 0; border: none; position: relative; z-index: 1; overflow: visible; }
.key.black::before {
  content: ''; position: absolute; left: -11px; top: 0; width: 22px; height: 56px; border-radius: 0 0 6px 6px;
  background: var(--ink-2); opacity: 0.85;
}
.key:active { background: var(--fill-strong); }
.key.black:active::before { opacity: 0.6; }

.meters { display: grid; grid-template-columns: auto 1fr 1fr; gap: 6px 10px; align-items: center; }
.meter { height: 6px; background: var(--fill); border-radius: 3px; overflow: hidden; }
.meter i { display: block; height: 100%; width: 0; background: var(--ink-2); border-radius: 3px; transition: width 0.06s linear; }
.meter i.hot { background: var(--warm); }

footer { max-width: 1080px; margin: 24px auto 0; }

@media (max-width: 860px) {
  main { grid-template-columns: 1fr 1fr; }
  .panel.wide { grid-column: span 2; }
}
@media (max-width: 600px) {
  main { grid-template-columns: 1fr; }
  .panel.wide { grid-column: auto; }
  .grid2 { grid-template-columns: 1fr; }
  .mode-line { font-size: 34px; }
  .keys { height: 110px; }
  button { min-height: 42px; }
  /* The inputs and outputs come first: they are chosen before starting. */
  .panel.audio { order: -1; }
  /* One octave (C to C) fits a phone. */
  .keys .key:nth-child(n + 14) { display: none; }
  .key.black::before { left: -9px; width: 18px; }
}