:root {
  color-scheme: dark;
  --ink: #e8f4ff;
  --muted: #8eb0d4;
  --line: rgba(120, 220, 255, 0.18);
  --panel: rgba(4, 10, 22, 0.62);
}
* { box-sizing: border-box; }
html, body {
  margin: 0;
  height: 100%;
  overflow: hidden;
  background: #02040a;
  font: 13px/1.45 "Segoe UI", "Helvetica Neue", sans-serif;
  color: var(--ink);
}
#viewport, #viewport canvas {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
  display: block;
}
#hud {
  position: absolute;
  top: 18px;
  left: 18px;
  width: min(270px, calc(100vw - 36px));
  padding: 16px 16px 14px;
  border: 1px solid var(--line);
  border-radius: 18px;
  background: var(--panel);
  box-shadow: 0 18px 60px rgba(0, 0, 0, 0.45);
  backdrop-filter: blur(16px);
}
.kicker {
  margin: 0 0 4px;
  letter-spacing: 0.16em;
  text-transform: uppercase;
  font-size: 9px;
  color: #c9d4ff;
}
h1 {
  margin: 0;
  font-size: 22px;
  font-weight: 600;
  letter-spacing: -0.03em;
}
#status { margin: 6px 0 0; color: var(--muted); }
label {
  display: grid;
  grid-template-columns: 1fr auto;
  gap: 2px 10px;
  margin: 8px 0;
  color: var(--muted);
}
label span { color: var(--ink); font-variant-numeric: tabular-nums; }
input[type=range] { grid-column: 1 / -1; width: 100%; accent-color: #d7dcff; }
button {
  width: 100%;
  margin-top: 8px;
  border: 1px solid var(--line);
  background: rgba(255, 255, 255, 0.06);
  color: var(--ink);
  border-radius: 10px;
  padding: 8px 10px;
  cursor: pointer;
}
.hint { margin: 10px 0 0; color: var(--muted); font-size: 11px; }
#error {
  position: absolute;
  left: 18px;
  right: 18px;
  bottom: 18px;
  max-height: 40vh;
  overflow: auto;
  padding: 12px;
  border-radius: 12px;
  background: #3a1010;
  color: #ffd9d9;
  white-space: pre-wrap;
}
@media (max-width: 720px) {
  #hud { top: auto; bottom: 8px; left: 8px; right: 8px; width: auto; }
}