/* System fonts only: no third-party request leaves this page. */
:root {
  --bg: #0d1117;
  --panel: #161b22;
  --line: #30363d;
  --text: #e6edf3;
  --muted: #9198a1;
  --accent: #4fa8e0;
  --warn-bg: #2b1d12;
  --warn-line: #7a4b1e;
  --warn-text: #f0c48a;
}

* { box-sizing: border-box; }

body {
  margin: 0;
  background: var(--bg);
  color: var(--text);
  font: 16px/1.6 -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto,
        "Helvetica Neue", Arial, sans-serif;
  padding: 0 16px 48px;
}

header, main, footer { max-width: 920px; margin: 0 auto; }

h1 { font-size: 1.45rem; margin: 28px 0 8px; line-height: 1.3; }
h2 { font-size: 1.05rem; margin: 28px 0 8px; }

.lead { color: var(--muted); margin: 0 0 16px; }

.warn {
  background: var(--warn-bg);
  border: 1px solid var(--warn-line);
  color: var(--warn-text);
  border-radius: 8px;
  padding: 12px 14px;
  margin: 0 0 24px;
  font-size: 0.93rem;
}

nav#cases { display: flex; flex-wrap: wrap; gap: 8px; margin-bottom: 16px; }

nav#cases button {
  background: var(--panel);
  border: 1px solid var(--line);
  color: var(--text);
  border-radius: 999px;
  padding: 8px 14px;
  font: inherit;
  font-size: 0.9rem;
  cursor: pointer;
}
nav#cases button[aria-pressed="true"] {
  border-color: var(--accent);
  color: var(--accent);
}

.stage {
  position: relative;
  background: #000;
  border: 1px solid var(--line);
  border-radius: 10px;
  overflow: hidden;
  aspect-ratio: 1 / 1;
  /* Tied to viewport height so the slider and the layer toggles stay on
     screen: a viewer whose controls are below the fold is not a viewer. */
  width: min(100%, 62vh);
  margin: 0 auto;
  touch-action: pan-y;
  user-select: none;
}

.stage img {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
  object-fit: contain;
  /* Nearest neighbour: a label must not be invented by the browser either. */
  image-rendering: pixelated;
}
.stage img#slice { image-rendering: auto; }
.layer { pointer-events: none; transition: opacity 120ms linear; }
.layer[hidden] { display: none; }

#hint {
  position: absolute;
  left: 0; right: 0; bottom: 8px;
  text-align: center;
  color: var(--muted);
  font-size: 0.8rem;
  margin: 0;
  pointer-events: none;
  transition: opacity 400ms linear;
}

.controls { margin-top: 14px; display: grid; gap: 12px; }

.slider { display: grid; gap: 6px; font-size: 0.9rem; color: var(--muted); }
.slider input { width: 100%; accent-color: var(--accent); }

.layers { display: flex; flex-wrap: wrap; gap: 14px; align-items: center;
          font-size: 0.9rem; }
.layers label { display: flex; align-items: center; gap: 6px; }
.opacity input { width: 120px; accent-color: var(--accent); }

.facts {
  margin: 18px 0 0;
  display: grid;
  grid-template-columns: max-content 1fr;
  gap: 4px 16px;
  font-size: 0.88rem;
}
.facts dt { color: var(--muted); }
.facts dd { margin: 0; }

.notes { color: var(--text); }
.notes p { color: var(--muted); }
.sources { color: var(--muted); padding-left: 20px; }
.sources li { margin-bottom: 6px; }
a { color: var(--accent); }
.fine { font-size: 0.85rem; }

footer {
  margin-top: 36px;
  padding-top: 16px;
  border-top: 1px solid var(--line);
  color: var(--muted);
  font-size: 0.85rem;
}

/* On a phone the screen is taller than it is wide, so the square may use the
   full width; the controls still fit underneath. */
@media (max-width: 560px) {
  h1 { font-size: 1.2rem; }
  .opacity input { width: 90px; }
  .stage { width: 100%; }
  .facts { grid-template-columns: 1fr; gap: 2px 0; }
  .facts dt { margin-top: 8px; }
}

/* --- tabs and the 3D stage ------------------------------------------- */

.tabs { display: flex; gap: 4px; margin: 0 0 12px; }

.tabs button {
  background: none;
  border: 0;
  border-bottom: 2px solid transparent;
  color: var(--muted);
  font: inherit;
  padding: 8px 14px;
  cursor: pointer;
}
.tabs button[aria-selected="true"] {
  color: var(--text);
  border-bottom-color: var(--accent);
}

.stage3d { background: #05080c; }
.stage3d canvas { width: 100%; height: 100%; display: block; touch-action: none; }

#loading3d {
  position: absolute;
  inset: 0;
  display: grid;
  place-content: center;
  margin: 0;
  color: var(--muted);
  font-size: 0.9rem;
  text-align: center;
  padding: 0 24px;
}
#loading3d[hidden] { display: none; }

.warn-inline { color: var(--warn-text); }

/* Per-part row: a toggle and its own opacity. */
#parts3d { display: grid; gap: 10px; }
#parts3d .part {
  display: grid;
  grid-template-columns: minmax(10rem, max-content) 1fr;
  align-items: center;
  gap: 12px;
}
#parts3d .part input[type="range"] { accent-color: var(--accent); max-width: 180px; }

@media (max-width: 560px) {
  #parts3d .part { grid-template-columns: 1fr; gap: 4px; }
  #parts3d .part input[type="range"] { max-width: none; }
}