:root {
  /* Blueprint navy ground — dark is the default drawing sheet. */
  --bg: #0d1b33;
  --bg-wash: #0a1628;
  --panel: #0f2140;
  --panel-2: #142a4d;
  --border: #2c4670;
  --border-dim: #1c3355;
  --text: #dce7f5;
  --text-dim: #82a0c4;
  --accent: #ffb454;      /* amber highlighter pen */
  --accent-2: #5fd6d1;    /* cyan drafting ink, secondary highlight */
  --risk: #ff7a5c;        /* warm coral-amber, distinct from --accent */
  --grid-line: rgba(140, 175, 220, 0.09);
  --grid-dot: rgba(140, 175, 220, 0.22);
  --shadow: 0 18px 40px rgba(3, 8, 20, 0.55);
  --font-mono: ui-monospace, "JetBrains Mono", "SFMono-Regular", "Cascadia Code", "Roboto Mono", Menlo, Consolas, monospace;
  font-family: var(--font-mono);
  font-variant-numeric: tabular-nums;
}

@media (prefers-color-scheme: light) {
  :root {
    /* Technical-paper ground — warm off-white sheet, navy ink. */
    --bg: #f1ecdd;
    --bg-wash: #e9e2cd;
    --panel: #faf7ee;
    --panel-2: #f2ecda;
    --border: #b9ac87;
    --border-dim: #d3c8a8;
    --text: #23324a;
    --text-dim: #5c6b85;
    --accent: #b6631a;
    --accent-2: #0d7a72;
    --risk: #a8402a;
    --grid-line: rgba(40, 55, 80, 0.09);
    --grid-dot: rgba(40, 55, 80, 0.22);
    --shadow: 0 18px 34px rgba(60, 50, 20, 0.14);
  }
}

* { box-sizing: border-box; }

body {
  margin: 0;
  background: var(--bg);
  background-image:
    linear-gradient(var(--bg-wash), var(--bg-wash)),
    repeating-linear-gradient(0deg, var(--grid-line) 0 1px, transparent 1px 32px),
    repeating-linear-gradient(90deg, var(--grid-line) 0 1px, transparent 1px 32px);
  background-blend-mode: normal;
  color: var(--text);
  min-height: 100vh;
  font-family: var(--font-mono);
}

.app {
  max-width: 1180px;
  margin: 0 auto;
  padding: 32px 24px 48px;
}

.app-header {
  margin-bottom: 24px;
}

.app-header__title {
  display: flex;
  align-items: baseline;
  gap: 14px;
  margin-bottom: 10px;
  flex-wrap: wrap;
}

.app-header__badge {
  font-size: 11px;
  font-weight: 700;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--accent);
  border: 1px solid var(--border);
  padding: 4px 9px;
  border-radius: 2px;
  font-family: var(--font-mono);
}

.app-header h1 {
  margin: 0;
  font-size: 27px;
  font-weight: 800;
  letter-spacing: 0.01em;
  font-family: var(--font-mono);
  text-transform: uppercase;
}

.app-header__subtitle {
  margin: 0;
  max-width: 780px;
  color: var(--text-dim);
  line-height: 1.55;
  font-size: 14px;
}

.stage-wrap {
  display: grid;
  grid-template-columns: minmax(0, 1.6fr) minmax(280px, 1fr);
  gap: 20px;
  align-items: start;
}

@media (max-width: 860px) {
  .stage-wrap { grid-template-columns: 1fr; }
}

.stage {
  position: relative;
  background: var(--panel);
  border: 1px solid var(--border);
  box-shadow: var(--shadow);
  padding: 10px;
}

/* Drafting registration ticks at the sheet's corners — the diagram's frame marks. */
.stage__tick {
  position: absolute;
  width: 16px;
  height: 16px;
  pointer-events: none;
  z-index: 2;
}
.stage__tick--tl { top: -1px; left: -1px; border-top: 2px solid var(--accent); border-left: 2px solid var(--accent); }
.stage__tick--tr { top: -1px; right: -1px; border-top: 2px solid var(--accent); border-right: 2px solid var(--accent); }
.stage__tick--bl { bottom: -1px; left: -1px; border-bottom: 2px solid var(--accent); border-left: 2px solid var(--accent); }
.stage__tick--br { bottom: -1px; right: -1px; border-bottom: 2px solid var(--accent); border-right: 2px solid var(--accent); }

#diagram {
  width: 100%;
  height: auto;
  display: block;
}

.diagram-grid {
  pointer-events: none;
}

.grid-line {
  fill: none;
  stroke: var(--grid-line);
  stroke-width: 1;
}

.grid-dot {
  fill: var(--grid-dot);
}

.node-frame {
  fill: var(--panel-2);
  stroke: var(--border);
  stroke-width: 1.25;
  transition: stroke 0.15s ease, fill 0.15s ease;
}

.node.node--data .node-frame {
  fill: var(--panel-2);
  stroke: var(--border);
  stroke-dasharray: 5 3;
}

.node-corner {
  fill: none;
  stroke: var(--border);
  stroke-width: 1.25;
  opacity: 0;
  transition: opacity 0.15s ease, stroke 0.15s ease;
}

.node {
  cursor: pointer;
}

.node:hover .node-frame,
.node:focus .node-frame,
.node.is-active .node-frame {
  stroke: var(--accent);
  fill: var(--panel-2);
}

.node:hover .node-corner,
.node:focus .node-corner,
.node.is-active .node-corner {
  opacity: 1;
  stroke: var(--accent);
}

.node.is-active .node-frame {
  stroke-width: 1.75;
}

.node:focus {
  outline: none;
}

.node-kicker {
  fill: var(--accent-2);
  font-size: 9px;
  font-weight: 700;
  letter-spacing: 0.12em;
}

.node-title {
  fill: var(--text);
  font-size: 15px;
  font-weight: 700;
}

.node-sub {
  fill: var(--text-dim);
  font-size: 10.5px;
}

.title-block__line {
  fill: var(--text-dim);
  font-size: 9.5px;
  letter-spacing: 0.06em;
}

.edge {
  fill: none;
  stroke: var(--border);
  stroke-width: 1.5;
  transition: stroke 0.15s ease, stroke-width 0.15s ease;
}

.edge.is-active {
  stroke: var(--accent);
  stroke-width: 2;
}

.arrow-head {
  fill: var(--border);
}

.edge.is-active + .arrow-head,
.edge-hit.is-active ~ .arrow-head {
  fill: var(--accent);
}

.edge-hit {
  fill: none;
  stroke: transparent;
  stroke-width: 18;
  cursor: pointer;
}

.detail {
  position: relative;
  background: var(--panel);
  border: 1px solid var(--border);
  box-shadow: var(--shadow);
  padding: 22px 20px;
  min-height: 300px;
}

.detail__tick {
  position: absolute;
  width: 14px;
  height: 14px;
  pointer-events: none;
}
.detail__tick--tl { top: -1px; left: -1px; border-top: 2px solid var(--accent-2); border-left: 2px solid var(--accent-2); }
.detail__tick--br { bottom: -1px; right: -1px; border-bottom: 2px solid var(--accent-2); border-right: 2px solid var(--accent-2); }

.detail__empty {
  color: var(--text-dim);
  font-size: 13px;
  line-height: 1.6;
}

.detail__hint {
  font-size: 12px;
  opacity: 0.8;
}

.detail__kicker {
  font-size: 10.5px;
  font-weight: 700;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--accent-2);
  margin: 0 0 6px;
}

.detail__title {
  margin: 0 0 16px;
  padding-bottom: 14px;
  border-bottom: 1px solid var(--border-dim);
  font-size: 19px;
  font-weight: 800;
  letter-spacing: 0.01em;
}

.detail__field {
  margin-bottom: 15px;
}

.detail__field-label {
  font-size: 10px;
  font-weight: 700;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--text-dim);
  margin: 0 0 5px;
}

.detail__field-value {
  margin: 0;
  font-size: 13.5px;
  line-height: 1.55;
}

.detail__field-value.risk {
  color: var(--risk);
}

.detail__deps {
  list-style: none;
  margin: 0;
  padding: 0;
  display: flex;
  flex-wrap: wrap;
  gap: 6px;
}

.detail__deps li {
  font-size: 11.5px;
  color: var(--text);
  background: var(--panel-2);
  border: 1px solid var(--border);
  border-radius: 2px;
  padding: 3px 8px;
}

.app-footer {
  margin-top: 28px;
  color: var(--text-dim);
  font-size: 12px;
  text-align: center;
}