/* Custom styles for "Gaussian Processes & Bayesian Optimization: An Interactive
   Tour". Distill's own web components (template.v2.js) supply the base page
   grid and typography; this file only styles the parts unique to this
   article: the interactive widgets and a few callout boxes. Colors follow a
   validated categorical palette (blue/orange/aqua/yellow), chosen so series
   stay distinguishable under common color-vision deficiencies. */

:root {
  --gpw-blue: #2a78d6;
  --gpw-orange: #eb6834;
  --gpw-aqua: #1baf7a;
  --gpw-yellow: #eda100;
  --gpw-ink: #0b0b0b;
  --gpw-secondary: #52514e;
  --gpw-muted: #898781;
  --gpw-grid: #e1e0d9;
  --gpw-baseline: #c3c2b7;
  --gpw-surface: #fcfcfb;
  --gpw-band: rgba(42, 120, 214, 0.16);
}

.gp-widget {
  border: 1px solid var(--gpw-baseline);
  border-radius: 8px;
  padding: 16px 18px 10px;
  background: var(--gpw-surface);
  margin: 1.6em 0;
}

.gpw-controls {
  display: flex;
  flex-wrap: wrap;
  gap: 14px 22px;
  align-items: center;
  font-size: 0.82rem;
  color: var(--gpw-secondary);
  margin-bottom: 6px;
}

.gpw-controls label {
  display: flex;
  align-items: center;
  gap: 6px;
  white-space: nowrap;
}

.gpw-controls input[type="range"] {
  width: 100px;
}

.gpw-controls select {
  font-size: 0.82rem;
  padding: 2px 4px;
}

.gpw-controls button {
  font-size: 0.8rem;
  padding: 5px 10px;
  border: 1px solid var(--gpw-baseline);
  background: white;
  border-radius: 5px;
  cursor: pointer;
  color: var(--gpw-ink);
}
.gpw-controls button:hover {
  background: #f0efec;
}

.gpw-svg {
  width: 100%;
  height: auto;
  display: block;
  touch-action: none;
}

.gpw-axis path,
.gpw-axis line {
  stroke: var(--gpw-baseline);
}
.gpw-axis text {
  fill: var(--gpw-muted);
  font-size: 10px;
}
.gpw-axislabel {
  fill: var(--gpw-secondary);
  font-size: 11px;
}

.gpw-band {
  fill: var(--gpw-band);
  stroke: none;
  pointer-events: none;
}
.gpw-mean {
  stroke: var(--gpw-blue);
  stroke-width: 2.4px;
  pointer-events: none;
}
.gpw-points circle,
.boe-svg .gpw-points circle {
  fill: var(--gpw-ink);
  stroke: var(--gpw-surface);
  stroke-width: 1.5px;
  cursor: grab;
}
.gpw-samples path {
  stroke: var(--gpw-orange);
  stroke-width: 1px;
  opacity: 0.55;
  pointer-events: none;
}

.gpw-caption {
  font-size: 0.78rem;
  color: var(--gpw-muted);
  margin: 4px 0 6px;
}
.gpw-caption span {
  color: var(--gpw-ink);
  font-weight: 600;
}

/* BO explorer specifics */
.boe-truth {
  stroke: var(--gpw-baseline);
  stroke-width: 1.6px;
  stroke-dasharray: 3 3;
}
.boe-next {
  stroke: var(--gpw-orange);
  stroke-width: 1.4px;
  stroke-dasharray: 4 3;
}
.boe-acq-path {
  stroke: var(--gpw-aqua);
  stroke-width: 2px;
}
.boe-acq-fill {
  fill: rgba(27, 175, 122, 0.14);
  stroke: none;
}

/* Callout / summary boxes reused across sections */
.callout {
  background: hsla(206, 90%, 20%, 0.035);
  border-left: 3px solid var(--gpw-blue);
  padding: 0.9em 1.4em;
  margin: 1.4em 0;
  font-size: 0.95em;
}
.callout.warn {
  border-left-color: var(--gpw-orange);
  background: hsla(20, 90%, 45%, 0.035);
}

.kernel-legend {
  display: flex;
  gap: 18px;
  flex-wrap: wrap;
  font-size: 0.82rem;
  color: var(--gpw-secondary);
  margin: 0.4em 0 1.2em;
}
.swatch {
  display: inline-block;
  width: 12px;
  height: 12px;
  border-radius: 2px;
  margin-right: 5px;
  vertical-align: -1px;
}

/* GP Playground: covariance-matrix heatmaps */
.gpw-heatmaps {
  display: flex;
  gap: 26px;
  flex-wrap: wrap;
  margin: 6px 0 4px;
}
.gpw-heatmap-block {
  flex: 1 1 200px;
  max-width: 220px;
}
.gpw-heatmap-label {
  font-size: 0.76rem;
  color: var(--gpw-secondary);
  margin: 0 0 4px;
}
.gpw-heatmap-label code {
  font-size: 0.72rem;
}
.gpw-heat-k,
.gpw-heat-kn {
  width: 100%;
  height: auto;
  border: 1px solid var(--gpw-baseline);
  border-radius: 4px;
}

/* Kernel Comparison Explorer */
.kc-legend-item {
  display: inline-flex;
  align-items: center;
  gap: 4px;
  font-size: 0.8rem;
}
.kc-xstar-line {
  stroke: var(--gpw-orange);
  stroke-width: 1.6px;
  stroke-dasharray: 4 3;
}
.kc-xstar-handle {
  fill: var(--gpw-orange);
  stroke: var(--gpw-surface);
  stroke-width: 1.5px;
  cursor: ew-resize;
}
.kc-table-wrap {
  overflow-x: auto;
}
.kc-table {
  width: 100%;
  border-collapse: collapse;
  font-size: 0.8rem;
  margin: 6px 0 10px;
}
.kc-table th,
.kc-table td {
  text-align: left;
  padding: 4px 10px 4px 0;
  border-bottom: 1px solid var(--gpw-grid);
  color: var(--gpw-secondary);
  white-space: nowrap;
}
.kc-table th {
  color: var(--gpw-muted);
  font-weight: 600;
  font-size: 0.72rem;
  text-transform: uppercase;
  letter-spacing: 0.02em;
}

/* Spatial Kriging Explorer */
.sk-svg {
  width: 100%;
  height: auto;
  display: block;
  touch-action: none;
  border-radius: 6px;
}
.sk-station {
  fill: var(--gpw-ink);
  stroke: white;
  stroke-width: 1.6px;
  cursor: grab;
}
.sk-label {
  font-size: 9.5px;
  fill: var(--gpw-ink);
  paint-order: stroke;
  stroke: white;
  stroke-width: 3px;
  pointer-events: none;
}
.sk-mode-toggle {
  gap: 4px !important;
}