:root {
  color-scheme: light;
  --paper: #f5f4ed;
  --panel: #faf9f5;
  --ink: #24221d;
  --muted: #6f6a5f;
  --rule: #d9d4c7;
  --accent: #1b365d;
  --green: #2f6f5e;
  --teal: #2e6f7f;
  --gold: #9b6a1b;
  --rose: #8a4f5f;
  --violet: #635a8a;
  --shadow: rgba(52, 44, 31, 0.12);
  font-family: Charter, Georgia, serif;
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  background: var(--paper);
  color: var(--ink);
}

button,
input,
select {
  font: inherit;
}

.graph-shell {
  min-height: 100vh;
  display: flex;
  flex-direction: column;
}

.graph-toolbar {
  padding: 12px 14px;
  border-bottom: 1px solid var(--rule);
  background: var(--panel);
}

.graph-controls,
.filter-row {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  align-items: center;
}

.filter-row {
  margin-top: 8px;
}

.control {
  display: grid;
  gap: 3px;
  color: var(--muted);
  font-size: 12px;
}

.control input,
.control select,
button {
  min-height: 32px;
  border: 1px solid var(--rule);
  border-radius: 6px;
  background: #fffef9;
  color: var(--ink);
}

.control input {
  width: min(42vw, 280px);
  padding: 5px 9px;
}

.control select {
  padding: 5px 28px 5px 8px;
}

.control-compact {
  width: 122px;
}

button {
  align-self: end;
  padding: 5px 12px;
  cursor: pointer;
}

button:hover,
.filter-toggle:hover {
  border-color: var(--accent);
}

.filter-toggle {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  min-height: 28px;
  padding: 4px 8px;
  border: 1px solid var(--rule);
  border-radius: 6px;
  background: #fffef9;
  color: var(--muted);
  font-size: 12px;
}

.filter-toggle input {
  margin: 0;
  accent-color: var(--accent);
}

.graph-main {
  min-height: 0;
  flex: 1;
  display: grid;
  grid-template-columns: minmax(0, 1fr) 280px;
}

.graph-canvas-wrap {
  position: relative;
  min-height: 540px;
  overflow: hidden;
  background:
    linear-gradient(rgba(36, 34, 29, 0.035) 1px, transparent 1px),
    linear-gradient(90deg, rgba(36, 34, 29, 0.035) 1px, transparent 1px),
    var(--paper);
  background-size: 32px 32px;
}

#concept-graph {
  display: block;
  width: 100%;
  height: 100%;
  min-height: 540px;
  cursor: grab;
  /* Background swipes can scroll the page vertically; horizontal swipes pan.
     Keep browser pinch zoom available too. */
  touch-action: pan-y pinch-zoom;
}

#concept-graph.is-dragging {
  cursor: grabbing;
}

.graph-details {
  padding: 14px;
  border-left: 1px solid var(--rule);
  background: var(--panel);
  overflow: auto;
}

.graph-details h2 {
  margin: 0 0 8px;
  font-size: 18px;
  line-height: 1.25;
  font-weight: 500;
}

.graph-details p {
  margin: 0 0 10px;
  color: var(--muted);
  line-height: 1.45;
  font-size: 13px;
}

.graph-details a {
  color: var(--accent);
}

.detail-meta {
  display: grid;
  gap: 6px;
  margin: 10px 0 14px;
  font-size: 12px;
}

.detail-meta span {
  color: var(--muted);
}

.detail-tags {
  display: flex;
  flex-wrap: wrap;
  gap: 5px;
}

.tag {
  padding: 3px 6px;
  border: 1px solid var(--rule);
  border-radius: 999px;
  background: #fffef9;
  color: var(--muted);
  font-size: 12px;
}

.edge {
  fill: none;
  stroke: #948d80;
  stroke-width: 1.4;
  vector-effect: non-scaling-stroke;
}

.edge-reference {
  stroke: #b5ab9b;
  stroke-dasharray: 4 5;
}

.edge-related {
  stroke: #a99aba;
  stroke-dasharray: 2 4;
}

.edge-muted,
.node-muted {
  opacity: 0.16;
}

.edge-highlight {
  opacity: 1;
  stroke-width: 2.3;
}

.node {
  cursor: pointer;
  /* A gesture starting on a node drags it in both axes. Set this before the
     gesture starts; changing touch-action during a drag would be too late. */
  touch-action: none;
}

.node circle {
  r: 10;
  fill: #fffef9;
  stroke-width: 2.2;
  vector-effect: non-scaling-stroke;
  filter: drop-shadow(0 2px 4px var(--shadow));
}

.node text {
  fill: var(--ink);
  paint-order: stroke;
  stroke: var(--paper);
  stroke-width: 4px;
  stroke-linejoin: round;
  font-size: 13px;
  pointer-events: none;
}

.node-selected circle,
.node-highlight circle {
  r: 13;
  stroke-width: 3;
}

.node-type-distribution circle {
  stroke: var(--green);
}

.node-type-theorem circle {
  stroke: var(--gold);
}

.node-type-method circle {
  stroke: var(--teal);
}

.node-type-empirical-example circle {
  stroke: var(--rose);
}

.node-type-definition circle {
  stroke: var(--violet);
}

.graph-error {
  padding: 16px;
  color: #7a2e2e;
}

@media (max-width: 760px) {
  .graph-main {
    grid-template-columns: 1fr;
  }

  .graph-details {
    border-left: 0;
    border-top: 1px solid var(--rule);
    max-height: 240px;
  }

  .control input {
    width: min(82vw, 320px);
  }
}

.node:focus { outline: none; }
.node:focus circle { stroke: #1B365D; stroke-width: 4px; }
.graph-help, .concept-list { padding: 1rem; }
.edge-proof-dependency { stroke-dasharray: 6 2; }
.edge-generalization { stroke: #28724F; stroke-dasharray: 2 3; }
.edge-application { stroke: #8F5A2A; }