/* Layout: the pendulum fills the stage on the left; a narrow
   instrument panel on the right holds controls and the spectrum.
   Below 860px the panel stacks under a square stage. */
:root {
  --bg:      #f4f5f7;
  --surface: #ffffff;
  --ink:     #14171c;
  --muted:   #646b78;
  --line:    #dadde3;
  --accent:  #2747c9;
  --accent-soft: rgba(39, 71, 201, 0.14);

  --font-sans: "IBM Plex Sans", system-ui, -apple-system, "Segoe UI", sans-serif;
  --font-mono: "IBM Plex Mono", ui-monospace, "SF Mono", Menlo, monospace;

  --step--1: 0.8rem;
  --step-0:  0.9rem;
  --step-1:  1.3rem;

  --panel-w: 320px;
  color-scheme: light;
}

@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) {
    --bg:      #0e1116;
    --surface: #161a21;
    --ink:     #e5e8ee;
    --muted:   #8b93a3;
    --line:    #2a303b;
    --accent:  #8ea2ff;
    --accent-soft: rgba(142, 162, 255, 0.16);
    color-scheme: dark;
  }
}

:root[data-theme="dark"] {
  --bg:      #0e1116;
  --surface: #161a21;
  --ink:     #e5e8ee;
  --muted:   #8b93a3;
  --line:    #2a303b;
  --accent:  #8ea2ff;
  --accent-soft: rgba(142, 162, 255, 0.16);
  color-scheme: dark;
}

* { box-sizing: border-box; }

html, body { height: 100%; }

body {
  margin: 0;
  background: var(--bg);
  color: var(--ink);
  font: 400 var(--step-0)/1.5 var(--font-sans);
  -webkit-font-smoothing: antialiased;
}

.app {
  display: grid;
  grid-template-columns: minmax(0, 1fr) var(--panel-w);
  gap: 32px;
  height: 100%;
  padding-block: 24px;
  padding-left: max(16px, env(safe-area-inset-left, 0px));
  padding-right: max(24px, env(safe-area-inset-right, 0px));
}

/* --- stage ---------------------------------------------------- */

.stage {
  position: relative;
  min-width: 0;
  min-height: 420px;
}

#chain {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
  touch-action: none;
  cursor: grab;
}

#chain.dragging { cursor: grabbing; }

.hint {
  position: absolute;
  left: 0;
  bottom: 0;
  margin: 0;
  color: var(--muted);
  font-size: var(--step--1);
  pointer-events: none;
}

/* --- panel ---------------------------------------------------- */

.panel {
  display: flex;
  flex-direction: column;
  gap: 20px;
  min-width: 0;
  min-height: 0;
  overflow-y: auto;
}

.intro h1 {
  margin: 0 0 6px;
  font-size: var(--step-1);
  font-weight: 600;
  letter-spacing: -0.01em;
  text-wrap: balance;
}

.intro p {
  margin: 0;
  color: var(--muted);
}

i { font-family: var(--font-sans); font-style: italic; }

/* transport */

.transport {
  display: flex;
  gap: 8px;
}

button {
  font: 500 var(--step-0) var(--font-sans);
  color: var(--ink);
  background: var(--surface);
  border: 1px solid var(--line);
  border-radius: 6px;
  padding: 6px 14px;
  cursor: pointer;
}

button:hover { border-color: var(--muted); }

button.primary {
  min-width: 84px;
  background: var(--accent);
  border-color: var(--accent);
  color: var(--surface);
}

button:focus-visible,
input:focus-visible + label,
input[type="range"]:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: 2px;
}

/* controls */

.controls {
  display: flex;
  flex-direction: column;
  gap: 12px;
  margin: 0;
}

.row {
  display: grid;
  grid-template-columns: 1fr auto;
  align-items: baseline;
  row-gap: 2px;
  margin: 0;
  padding: 0;
  border: 0;
  min-width: 0;
}

.row label,
.row legend {
  padding: 0;
  font-weight: 500;
}

.row output {
  font: 400 var(--step--1) var(--font-mono);
  font-variant-numeric: tabular-nums;
  color: var(--muted);
}

.row input[type="range"] {
  grid-column: 1 / -1;
  width: 100%;
  margin: 2px 0 0;
  accent-color: var(--accent);
}

/* segmented control */

.seg legend { float: left; }

.segs {
  grid-column: 1 / -1;
  display: flex;
  margin-top: 6px;
  border: 1px solid var(--line);
  border-radius: 6px;
  overflow: hidden;
}

.segs input {
  position: absolute;
  opacity: 0;
  pointer-events: none;
}

.segs label {
  flex: 1;
  text-align: center;
  padding: 5px 0;
  font-weight: 400;
  color: var(--muted);
  background: var(--surface);
  cursor: pointer;
}

.segs label + input + label { border-left: 1px solid var(--line); }

.segs input:checked + label {
  color: var(--accent);
  background: var(--accent-soft);
  font-weight: 500;
}

/* spectrum */

.spectrum { margin: 0; }

.spectrum figcaption {
  display: flex;
  flex-wrap: wrap;
  justify-content: space-between;
  gap: 4px 12px;
  margin-bottom: 6px;
  font-weight: 500;
}

.key {
  display: flex;
  align-items: center;
  gap: 6px;
  font-weight: 400;
  font-size: var(--step--1);
  color: var(--muted);
}

.key b {
  display: inline-block;
  width: 8px;
  height: 8px;
  border-radius: 50%;
}

.key b.avg { background: var(--accent); }
.key b.now { background: var(--muted); opacity: 0.5; margin-left: 6px; }

#spectrum {
  display: block;
  width: 100%;
  height: 170px;
}

/* readout */

.readout {
  display: grid;
  grid-template-columns: repeat(4, minmax(0, 1fr));
  gap: 8px;
  margin: 0;
}

.readout dt {
  font-size: var(--step--1);
  color: var(--muted);
  letter-spacing: 0.02em;
}

.readout dd {
  margin: 0;
  font: 400 var(--step--1) var(--font-mono);
  font-variant-numeric: tabular-nums;
  white-space: nowrap;
}

.status {
  margin: -8px 0 0;
  min-height: 1.5em;
  font-size: var(--step--1);
  color: var(--accent);
}

.note {
  margin: auto 0 0;
  font-size: var(--step--1);
  color: var(--muted);
}

/* --- narrow --------------------------------------------------- */

@media (max-width: 860px) {
  .app {
    grid-template-columns: minmax(0, 1fr);
    height: auto;
    gap: 20px;
    padding-block: 16px;
    padding-right: max(16px, env(safe-area-inset-right, 0px));
  }

  .stage {
    min-height: 0;
    aspect-ratio: 1;
    max-width: 100%;
    max-height: 80vh;
    order: 1;
  }

  .panel { display: contents; }
  .intro { order: 0; }
  .transport { order: 2; }
  .controls { order: 3; }
  .spectrum { order: 4; }
  .readout { order: 5; grid-template-columns: repeat(2, minmax(0, 1fr)); }
  .status { order: 6; margin: 0; }
  .note { order: 7; margin: 0; }
}