:root {
  --bg: #0d1017;
  --panel: #151922;
  --panel-2: #1b202b;
  --line: #262c39;
  --text: #dfe3ea;
  --muted: #8d96a8;
  --accent: #6ea8fe;
  --error: #ff7b72;
  --warn: #e3b341;
  --good: #56d364;
}

* { box-sizing: border-box; }

/* Author-level `display` on .placeholder outranks the UA stylesheet's
   [hidden] { display: none }, so toggling el.hidden alone would leave it on
   screen. Restate it here with priority. */
[hidden] { display: none !important; }

html, body {
  height: 100%;
  margin: 0;
}

body {
  background: var(--bg);
  color: var(--text);
  font: 14px/1.5 ui-sans-serif, system-ui, -apple-system, "Segoe UI", sans-serif;
  display: flex;
  flex-direction: column;
}

/* ------------------------------------------------------------- topbar */

.topbar {
  display: flex;
  align-items: center;
  gap: 20px;
  padding: 10px 18px;
  background: var(--panel);
  border-bottom: 1px solid var(--line);
  flex: 0 0 auto;
}

.topbar h1 {
  font-size: 15px;
  font-weight: 600;
  margin: 0;
  letter-spacing: 0.02em;
}

.model-file {
  color: var(--muted);
  font-family: ui-monospace, SFMono-Regular, Menlo, monospace;
  font-size: 12px;
  margin-left: auto;
}

input[type="number"], button {
  font: inherit;
  color: var(--text);
  background: var(--panel-2);
  border: 1px solid var(--line);
  border-radius: 6px;
  padding: 6px 9px;
}

input[type="number"] {
  width: 100%;
  text-align: right;
  font-variant-numeric: tabular-nums;
}

input[type="number"]:focus {
  outline: 2px solid var(--accent);
  outline-offset: -1px;
}

button {
  cursor: pointer;
}

button:hover:not(:disabled) {
  border-color: var(--accent);
}

button:disabled {
  opacity: 0.45;
  cursor: not-allowed;
}

button.primary {
  background: var(--accent);
  border-color: var(--accent);
  color: #08101f;
  font-weight: 600;
}

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

.layout {
  flex: 1 1 auto;
  display: grid;
  grid-template-columns: 340px 1fr;
  min-height: 0;
}

.sidebar {
  background: var(--panel);
  border-right: 1px solid var(--line);
  padding: 16px;
  overflow-y: auto;
  display: flex;
  flex-direction: column;
  gap: 14px;
}

.model-desc {
  margin: 0;
  color: var(--muted);
  font-size: 13px;
}

fieldset {
  border: 1px solid var(--line);
  border-radius: 8px;
  padding: 10px 12px 4px;
  margin: 0 0 12px;
}

legend {
  color: var(--accent);
  font-size: 11px;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  padding: 0 6px;
}

.field {
  margin-bottom: 10px;
}

.field label {
  display: flex;
  align-items: baseline;
  gap: 6px;
  font-size: 13px;
  margin-bottom: 3px;
}

.range-note {
  color: var(--muted);
  font-size: 11px;
  opacity: 0.7;
  font-variant-numeric: tabular-nums;
  white-space: nowrap;
}

.input-wrap {
  display: flex;
  align-items: center;
  gap: 8px;
}

.input-wrap input[type="number"] {
  flex: 0 0 78px;
  width: 78px;
}

/* The sliders already cover nudging a value, so drop the native spinners and
   keep the number box narrow. */
.input-wrap input[type="number"] {
  -moz-appearance: textfield;
  appearance: textfield;
}

.input-wrap input[type="number"]::-webkit-outer-spin-button,
.input-wrap input[type="number"]::-webkit-inner-spin-button {
  -webkit-appearance: none;
  appearance: none;
  margin: 0;
}

.input-wrap .unit {
  color: var(--muted);
  font-size: 12px;
  min-width: 22px;
}

/* ------------------------------------------------------------- sliders */

input[type="range"].slider {
  flex: 1 1 auto;
  min-width: 0;
  appearance: none;
  -webkit-appearance: none;
  height: 18px;
  background: transparent;
  padding: 0;
  border: 0;
  cursor: pointer;
}

input[type="range"].slider::-webkit-slider-runnable-track {
  height: 4px;
  border-radius: 2px;
  background: var(--line);
}

input[type="range"].slider::-moz-range-track {
  height: 4px;
  border-radius: 2px;
  background: var(--line);
}

input[type="range"].slider::-webkit-slider-thumb {
  -webkit-appearance: none;
  width: 14px;
  height: 14px;
  margin-top: -5px;
  border-radius: 50%;
  background: var(--accent);
  border: none;
}

input[type="range"].slider::-moz-range-thumb {
  width: 14px;
  height: 14px;
  border-radius: 50%;
  background: var(--accent);
  border: none;
}

input[type="range"].slider:hover::-webkit-slider-thumb,
input[type="range"].slider:active::-webkit-slider-thumb {
  background: #9ec5ff;
}

input[type="range"].slider:hover::-moz-range-thumb,
input[type="range"].slider:active::-moz-range-thumb {
  background: #9ec5ff;
}

.field .help {
  margin: 3px 0 0;
  font-size: 11px;
  color: var(--muted);
}

.field.invalid input {
  border-color: var(--error);
}

.panel h2 {
  font-size: 11px;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--accent);
  margin: 0 0 8px;
}

#derived-list {
  display: grid;
  grid-template-columns: 1fr auto;
  gap: 3px 12px;
  margin: 0;
  font-size: 12px;
}

#derived-list dt { color: var(--muted); }

#derived-list dd {
  margin: 0;
  text-align: right;
  font-variant-numeric: tabular-nums;
}

.messages {
  display: flex;
  flex-direction: column;
  gap: 6px;
}

.msg {
  font-size: 12px;
  padding: 7px 9px;
  border-radius: 6px;
  border-left: 3px solid;
}

.msg.error {
  color: var(--error);
  background: rgba(255, 123, 114, 0.09);
  border-color: var(--error);
}

.msg.warning {
  color: var(--warn);
  background: rgba(227, 179, 65, 0.09);
  border-color: var(--warn);
}

.actions {
  display: flex;
  gap: 8px;
  flex-wrap: wrap;
  align-items: center;
  margin-top: auto;
  padding-top: 8px;
  position: sticky;
  bottom: 0;
  background: var(--panel);
}

/* Quiet progress hint for rebuilds triggered by editing, so the whole page is
   not blocked by the overlay on every keystroke. */
.live-indicator {
  position: absolute;
  top: 10px;
  left: 10px;
  font-size: 12px;
  color: var(--accent);
  background: rgba(21, 25, 34, 0.9);
  border: 1px solid var(--line);
  border-radius: 999px;
  padding: 3px 10px;
  pointer-events: none;
  animation: pulse 1.1s ease-in-out infinite;
}

@keyframes pulse {
  50% { opacity: 0.45; }
}

/* ------------------------------------------------------------ content */

.content {
  display: flex;
  flex-direction: column;
  min-width: 0;
  min-height: 0;
  overflow: hidden;
}

.viewer-wrap {
  position: relative;
  flex: 1 1 auto;
  height: auto;
  min-height: 160px;
}

#viewer {
  position: absolute;
  inset: 0;
}

#viewer canvas { display: block; }

.viewer-overlay {
  position: absolute;
  top: 10px;
  right: 10px;
  display: flex;
  gap: 6px;
  flex-wrap: wrap;
  justify-content: flex-end;
}

.viewer-overlay button {
  background: rgba(21, 25, 34, 0.85);
  font-size: 12px;
  padding: 4px 8px;
}

.placeholder {
  position: absolute;
  inset: 0;
  display: grid;
  place-items: center;
  color: var(--muted);
  pointer-events: none;
}

.stats {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  padding: 10px 14px;
  border-bottom: 1px solid var(--line);
  background: var(--panel);
  min-height: 20px;
  flex: 0 0 auto;
}

.pill {
  font-size: 12px;
  background: var(--panel-2);
  border: 1px solid var(--line);
  border-radius: 999px;
  padding: 3px 10px;
  font-variant-numeric: tabular-nums;
}

.pill b {
  color: var(--muted);
  font-weight: 500;
  margin-right: 6px;
}

/* Below this the fixed-width sidebar would leave almost nothing for the
   viewer, so stack the two columns and let the page scroll instead. */
@media (max-width: 900px) {
  .layout {
    grid-template-columns: 1fr;
    grid-template-rows: auto auto;
    overflow-y: auto;
  }

  .sidebar {
    border-right: none;
    border-bottom: 1px solid var(--line);
    overflow: visible;
  }

  .actions { position: static; }

  .content { overflow: visible; }

  .topbar { flex-wrap: wrap; gap: 10px 16px; }
  .model-file { margin-left: 0; }
}

/* -------------------------------------------------------- advanced fold */

details.advanced {
  border: 1px solid var(--line);
  border-radius: 8px;
  margin-bottom: 12px;
  background: rgba(0, 0, 0, 0.12);
}

details.advanced > summary {
  cursor: pointer;
  padding: 8px 12px;
  font-size: 11px;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--muted);
  list-style: none;
  user-select: none;
}

details.advanced > summary::-webkit-details-marker { display: none; }

/* Disclosure triangle, drawn so it works the same in every browser. */
details.advanced > summary::before {
  content: '';
  display: inline-block;
  width: 0;
  height: 0;
  margin-right: 8px;
  vertical-align: 1px;
  border-left: 5px solid currentColor;
  border-top: 4px solid transparent;
  border-bottom: 4px solid transparent;
  transition: transform 0.12s ease;
}

details.advanced[open] > summary::before { transform: rotate(90deg); }

details.advanced > summary:hover { color: var(--accent); }

details.advanced > fieldset {
  margin: 0 10px 10px;
}

details.advanced > fieldset:first-of-type { margin-top: 4px; }