/* ==========================================================================
   Signed RF playgrounds — shared design system.
   One visual language with the deck: cream paper, KaTeX_Main serif,
   ultramarine + magenta, hairline panels, pill controls.
   ========================================================================== */

:root {
  --bg: #fdfbf7;
  --ink: #303a49;
  --muted: #536073;
  --faint: rgba(48, 58, 73, 0.52);
  --prim: #3250bc;
  --prim-light: #4969e2;
  --prim-dark: #253a88;
  --mag: #e34a92;
  --mag-dark: #9d2d64;
  --panel: #fbfcff;
  --panel-border: #d6ddf3;
  --chip-border: #c9d2e8;
  --chip-on: #eaf0ff;
  --track: #d6ddf3;
  --hairline: rgba(48, 58, 73, 0.16);
  --serif: 'KaTeX_Main', 'STIX Two Text', Georgia, serif;
}

* {
  box-sizing: border-box;
}

html,
body {
  margin: 0;
  padding: 0;
  background: var(--bg);
  color: var(--ink);
  font-family: var(--serif);
  font-size: 16px;
}

body {
  min-height: 100vh;
  display: flex;
  flex-direction: column;
}

/* ---- Header ------------------------------------------------------------- */

header.pg-header {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  gap: 16px;
  width: 100%;
  max-width: 1280px;
  margin: 0 auto;
  padding: 22px 28px 14px;
  border-bottom: 1px solid var(--hairline);
}

.pg-title {
  font-size: 21px;
  font-weight: 700;
  color: var(--prim);
  letter-spacing: 0;
}

.pg-title .pg-title-sub {
  color: var(--muted);
  font-weight: 600;
  font-size: 16px;
}

nav.pg-nav {
  display: flex;
  gap: 18px;
  font-size: 13.5px;
  white-space: nowrap;
}

nav.pg-nav a {
  color: var(--muted);
  text-decoration: none;
  border-bottom: 1px solid transparent;
  padding-bottom: 1px;
}

nav.pg-nav a:hover {
  color: var(--prim-dark);
  border-bottom-color: var(--prim-light);
}

/* ---- Main layout ---------------------------------------------------------- */

main.pg-main {
  flex: 1 0 auto;
  display: flex;
  gap: 24px;
  align-items: center;
  width: 100%;
  max-width: 1280px;
  margin: 0 auto;
  padding: 16px 28px 48px;
}

.pg-stage {
  position: relative;
  flex: 1 1 auto;
  min-width: 0;
  background: var(--panel);
  border: 1px solid var(--panel-border);
  border-radius: 10px;
  box-shadow: 0 3px 10px rgba(27, 42, 74, 0.1);
  overflow: hidden;
}

.pg-stage canvas,
.pg-stage svg {
  display: block;
  width: 100%;
  height: auto;
}

.pg-stage .pg-layer {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
  pointer-events: none;
}

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

aside.pg-controls {
  flex: 0 0 272px;
  display: flex;
  flex-direction: column;
  gap: 18px;
  font-size: 13.5px;
}

.pg-group {
  display: flex;
  flex-direction: column;
  gap: 8px;
}

.pg-group-label {
  font-size: 11.5px;
  font-weight: 700;
  letter-spacing: 0.09em;
  text-transform: lowercase;
  color: var(--faint);
}

.pg-chips {
  display: flex;
  flex-wrap: wrap;
  gap: 6px;
}

.pg-chip {
  appearance: none;
  font-family: var(--serif);
  font-size: 12.5px;
  font-weight: 650;
  color: var(--muted);
  background: #ffffff;
  border: 1px solid var(--chip-border);
  border-radius: 12px;
  padding: 3.5px 11px 4.5px;
  cursor: pointer;
  user-select: none;
  touch-action: manipulation;
}

.pg-chip:hover {
  border-color: var(--prim-dark);
}

.pg-chip.on {
  background: var(--chip-on);
  border: 1.4px solid var(--prim-dark);
  color: var(--prim-dark);
  padding: 3.1px 10.6px 4.1px;
}

/* Layer toggles: same pill, with a state dot. */
.pg-toggle::before {
  content: '';
  display: inline-block;
  width: 7px;
  height: 7px;
  border-radius: 50%;
  margin-right: 7px;
  background: transparent;
  border: 1.4px solid var(--chip-border);
  vertical-align: 1px;
}

.pg-toggle.on::before {
  background: var(--prim-light);
  border-color: var(--prim-dark);
}

/* ---- Slider row -------------------------------------------------------------- */

.pg-slider-row {
  display: flex;
  align-items: center;
  gap: 12px;
}

.pg-slider-row .pg-readout {
  min-width: 74px;
  text-align: right;
  color: var(--prim-dark);
  font-size: 13.5px;
  font-weight: 650;
  white-space: nowrap;
}

input[type='range'].pg-range {
  appearance: none;
  -webkit-appearance: none;
  flex: 1 1 auto;
  height: 26px;
  margin: 0;
  background: transparent;
  --fill: 50%;
  cursor: pointer;
  touch-action: none;
}

input[type='range'].pg-range::-webkit-slider-runnable-track {
  height: 8px;
  border-radius: 4px;
  background: linear-gradient(to right, var(--prim-light) var(--fill), var(--track) var(--fill));
}

input[type='range'].pg-range::-webkit-slider-thumb {
  -webkit-appearance: none;
  width: 20px;
  height: 20px;
  margin-top: -6px;
  border-radius: 50%;
  background: #ffffff;
  border: 2.2px solid var(--prim-dark);
  box-shadow: 0 1px 3px rgba(27, 42, 74, 0.22);
}

input[type='range'].pg-range::-moz-range-track {
  height: 8px;
  border-radius: 4px;
  background: var(--track);
}

input[type='range'].pg-range::-moz-range-progress {
  height: 8px;
  border-radius: 4px;
  background: var(--prim-light);
}

input[type='range'].pg-range::-moz-range-thumb {
  width: 16px;
  height: 16px;
  border-radius: 50%;
  background: #ffffff;
  border: 2.2px solid var(--prim-dark);
}

/* ---- Buttons -------------------------------------------------------------------- */

.pg-btn-row {
  display: flex;
  align-items: center;
  gap: 10px;
}

.pg-btn {
  appearance: none;
  font-family: var(--serif);
  font-size: 12.5px;
  font-weight: 650;
  color: var(--muted);
  background: #ffffff;
  border: 1px solid var(--chip-border);
  border-radius: 12px;
  padding: 4px 13px 5px;
  cursor: pointer;
}

.pg-btn:hover {
  border-color: var(--prim-dark);
  color: var(--prim-dark);
}

.pg-play {
  width: 30px;
  height: 30px;
  border-radius: 50%;
  border: 2px solid var(--prim-dark);
  background: #ffffff;
  cursor: pointer;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 0;
}

.pg-play svg {
  display: block;
}

/* KaTeX inside controls */
aside.pg-controls .katex {
  font-size: 1.05em;
}

/* ---- Narrow screens ------------------------------------------------------------------ */

@media (max-width: 860px) {
  header.pg-header {
    padding: 14px 16px 10px;
  }

  .pg-title {
    font-size: 17px;
  }

  .pg-title .pg-title-sub {
    font-size: 13.5px;
  }

  nav.pg-nav {
    gap: 12px;
    font-size: 12.5px;
  }

  main.pg-main {
    flex-direction: column;
    gap: 16px;
    padding: 12px 14px 32px;
  }

  /* In the stacked layout the stage must NOT flex-grow: with the column
     direction that stretches it vertically past its content and letterboxes
     the SVG inside a tall empty card. Size it by its own aspect ratio. */
  .pg-stage {
    flex: 0 0 auto;
    width: 100%;
  }

  aside.pg-controls {
    flex-basis: auto;
    width: 100%;
  }
}