:root {
  --paper: #ece5d6;
  --ink: #2b2620;
  --muted: #7a6f60;
  --rule: #cfc4ae;
  --accent: #a3341f;
  --card: rgba(248, 244, 235, 0.86);
  --serif: 'Iowan Old Style', 'Palatino Linotype', Palatino, Georgia, serif;
  --mono: ui-monospace, 'JetBrains Mono', 'SF Mono', Menlo, monospace;
}

* { box-sizing: border-box; }

html, body {
  margin: 0;
  height: 100%;
  overflow: hidden;
  color: var(--ink);
  font-family: var(--serif);
  background:
    radial-gradient(ellipse at 50% 40%, #f6f1e6 0%, var(--paper) 55%, #d9cfba 100%);
}

body::before {
  /* faint graticule */
  content: '';
  position: fixed;
  inset: 0;
  background-image:
    linear-gradient(rgba(120, 100, 70, 0.07) 1px, transparent 1px),
    linear-gradient(90deg, rgba(120, 100, 70, 0.07) 1px, transparent 1px);
  background-size: 64px 64px;
  pointer-events: none;
}

#gpu {
  position: fixed;
  inset: 0;
  width: 100%;
  height: 100%;
  touch-action: none;
  cursor: grab;
}
#gpu:active { cursor: grabbing; }

#loading {
  position: fixed;
  inset: 0;
  display: grid;
  place-items: center;
  font: 14px var(--mono);
  color: var(--muted);
  letter-spacing: 0.08em;
}
#loading.error { color: var(--accent); }

.panel, .legend {
  position: fixed;
  background: var(--card);
  backdrop-filter: blur(8px);
  border: 1px solid var(--rule);
  box-shadow: 0 1px 0 #fff inset, 0 10px 30px rgba(60, 45, 25, 0.12);
}

.panel {
  top: 20px;
  left: 20px;
  width: 280px;
  padding: 20px 20px 18px;
}

.eyebrow {
  margin: 0 0 6px;
  font: 10px var(--mono);
  letter-spacing: 0.18em;
  text-transform: uppercase;
  color: var(--accent);
}

h1 {
  margin: 0;
  font-size: 22px;
  font-weight: 600;
  line-height: 1.15;
}

.sub {
  margin: 8px 0 0;
  font-size: 13px;
  line-height: 1.45;
  color: var(--muted);
  font-style: italic;
}

section {
  margin-top: 16px;
  padding-top: 12px;
  border-top: 1px solid var(--rule);
}

h2 {
  margin: 0 0 8px;
  font: 10px var(--mono);
  letter-spacing: 0.16em;
  text-transform: uppercase;
  color: var(--muted);
}

label {
  display: block;
  font-size: 13px;
  margin-bottom: 8px;
}

output {
  float: right;
  font: 11px var(--mono);
  color: var(--muted);
}

input[type='range'] {
  width: 100%;
  margin: 4px 0 0;
  accent-color: var(--ink);
  height: 14px;
}

.toggles {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 2px 10px;
}
.toggles label { margin: 0; }
input[type='checkbox'] { accent-color: var(--ink); vertical-align: -2px; }

button {
  width: 100%;
  margin-top: 14px;
  padding: 9px;
  font: 11px var(--mono);
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--paper);
  background: var(--ink);
  border: 0;
  cursor: pointer;
}
button:hover { background: var(--accent); }

.legend {
  top: 20px;
  right: 20px;
  width: 240px;
  padding: 16px 18px;
}

.legend ul {
  list-style: none;
  margin: 0;
  padding: 0;
}

.legend li {
  display: grid;
  grid-template-columns: 22px 1fr auto;
  align-items: center;
  gap: 8px;
  padding: 3px 0;
  font-size: 12.5px;
}

.sw {
  width: 22px;
  height: 13px;
  border: 1px solid rgba(40, 30, 20, 0.45);
}

.ag {
  font: 9.5px var(--mono);
  color: var(--muted);
  text-align: right;
}

.key {
  margin: 10px 0 0;
  padding-top: 8px;
  border-top: 1px solid var(--rule);
  font-size: 12.5px;
  display: flex;
  align-items: center;
  gap: 8px;
}
.key .fault {
  width: 22px;
  height: 0;
  border-top: 2.5px solid #8c1217;
}

.hint {
  position: fixed;
  bottom: 14px;
  left: 50%;
  transform: translateX(-50%);
  margin: 0;
  font: 11px var(--mono);
  letter-spacing: 0.06em;
  color: var(--muted);
  pointer-events: none;
}

@media (max-width: 760px) {
  .legend { display: none; }
  .panel { width: calc(100% - 40px); }
}

body[data-mode='terrain'] .geo-only,
body[data-mode='geology'] .terrain-only { display: none; }

.modes {
  display: grid;
  grid-template-columns: 1fr 1fr;
  margin-top: 14px;
  border: 1px solid var(--ink);
}
.modes button {
  margin: 0;
  padding: 7px;
  color: var(--ink);
  background: transparent;
}
.modes button[aria-pressed='true'] {
  color: var(--paper);
  background: var(--ink);
}
.modes button:hover { background: rgba(43, 38, 32, 0.12); }
.modes button[aria-pressed='true']:hover { background: var(--ink); }