.expansion-sequence {
  --sequence-establish: var(--accent-contrast);
  --sequence-reuse: var(--green);
  --sequence-prior: var(--line-strong);
  --sequence-future: var(--line-strong);
  min-width: 0;
  margin: 48px 0 0;
}

.sequence-defs {
  display: none;
}

.sequence-heading {
  display: flex;
  flex-wrap: wrap;
  gap: 8px 16px;
  align-items: baseline;
  justify-content: space-between;
  padding-bottom: 12px;
  border-bottom: 1px solid var(--line-strong);
  color: var(--paper-muted);
  font-family: var(--mono);
  font-size: 11px;
  text-transform: uppercase;
}

.sequence-heading span:first-child {
  color: var(--paper);
}

.sequence-grid {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 1px;
  border: 1px solid var(--line);
  border-top: 0;
  background: var(--line);
}

.sequence-card {
  display: flex;
  min-width: 0;
  flex-direction: column;
  padding: 16px;
  background: var(--bg-elevated);
}

.sequence-card-heading {
  display: flex;
  gap: 10px;
  align-items: baseline;
  color: var(--paper-muted);
  font-family: var(--mono);
  font-size: 10px;
  text-transform: uppercase;
}

.sequence-time {
  color: var(--sequence-establish);
  font-size: 11px;
}

.sequence-card h3 {
  margin: 8px 0 0;
  font-size: 15px;
  font-weight: 400;
}

.sequence-diagram {
  display: block;
  width: 100%;
  max-width: 306px;
  height: auto;
  margin: 16px auto 0;
  font-family: var(--mono);
  font-size: 11px;
  text-anchor: middle;
  shape-rendering: geometricPrecision;
}

.sequence-diagram path {
  vector-effect: non-scaling-stroke;
}

.sequence-guide {
  fill: none;
  stroke: var(--line-faint);
}

.sequence-path {
  fill: none;
  stroke-width: 1.5;
}

.sequence-establish {
  stroke: var(--sequence-establish);
}

.sequence-reuse {
  stroke: var(--sequence-reuse);
}

.sequence-history {
  stroke: var(--sequence-prior);
}

/*
  Diagram geometry lives once in the figure's <defs> sprite; each snapshot
  composes it with <use> references wrapped in one group per state. Shape
  fill/stroke inherit from the state group into the use clones; label fills
  route through the two custom properties because layer labels (F1-F7) and
  capability labels need different foregrounds within the same state.
*/
.sequence-state {
  fill: var(--bg-elevated);
  stroke-width: 1;
}

.sequence-state-first {
  fill: var(--accent);
  stroke: var(--accent);
  --sequence-cap-label: var(--on-accent);
}

.sequence-state-new {
  stroke: var(--sequence-establish);
}

.sequence-state-prior {
  stroke: var(--sequence-prior);
}

.sequence-state-current {
  stroke: var(--sequence-reuse);
  --sequence-cap-label: var(--sequence-reuse);
}

.sequence-state-future {
  fill: none;
  stroke: var(--sequence-future);
  stroke-dasharray: 3 3;
  --sequence-layer-label: var(--line-strong);
  --sequence-cap-label: var(--line-strong);
}

.sequence-layer text {
  fill: var(--sequence-layer-label, var(--paper));
}

.sequence-cap text {
  fill: var(--sequence-cap-label, var(--paper-muted));
}

.sequence-metrics {
  display: grid;
  gap: 6px;
  margin: 16px 0 0;
  color: var(--paper-muted);
  font-family: var(--mono);
  font-size: 10px;
  text-transform: uppercase;
}

.sequence-metrics div {
  display: flex;
  justify-content: space-between;
}

.sequence-metrics dt,
.sequence-metrics dd {
  margin: 0;
}

.sequence-metrics dd {
  color: var(--paper);
}

.sequence-metrics .sequence-metric-new {
  color: var(--sequence-establish);
}

.sequence-metrics .sequence-metric-reuse {
  color: var(--sequence-reuse);
}

/* Per-snapshot data: new/reused layer counts size the balance bar segments. */
.sequence-card:nth-child(1) {
  --sequence-new-layers: 5;
  --sequence-reused-layers: 0;
}

.sequence-card:nth-child(2) {
  --sequence-new-layers: 1;
  --sequence-reused-layers: 4;
}

.sequence-card:nth-child(3) {
  --sequence-new-layers: 1;
  --sequence-reused-layers: 5;
}

.sequence-card:nth-child(4) {
  --sequence-new-layers: 0;
  --sequence-reused-layers: 7;
}

.sequence-balance {
  display: flex;
  gap: 1px;
  height: 4px;
  margin-top: 10px;
}

.sequence-balance-new {
  flex: var(--sequence-new-layers);
  background: var(--accent);
}

.sequence-balance-reuse {
  flex: var(--sequence-reused-layers);
  background: var(--sequence-reuse);
}

.sequence-foundations {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 1px;
  margin: 24px 0 0;
  padding: 1px;
  background: var(--line);
  list-style: none;
}

.sequence-foundations li {
  display: flex;
  gap: 8px;
  min-width: 0;
  padding: 12px 14px;
  background: var(--bg-elevated);
  color: var(--paper-muted);
  font-family: var(--mono);
  font-size: 11px;
}

.sequence-foundations span {
  flex: 0 0 auto;
  color: var(--sequence-establish);
}

.expansion-sequence figcaption {
  display: flex;
  flex-wrap: wrap;
  gap: 10px 24px;
  align-items: center;
  margin-top: 16px;
  color: var(--paper-muted);
  font-family: var(--mono);
  font-size: 11px;
  text-transform: uppercase;
}

.expansion-sequence figcaption > span {
  display: inline-flex;
  gap: 8px;
  align-items: center;
}

.expansion-sequence figcaption strong {
  color: var(--paper-muted);
  font-weight: 400;
  text-transform: none;
}

.sequence-key {
  display: inline-block;
  width: 16px;
  height: 2px;
}

.sequence-key-establish {
  background: var(--sequence-establish);
}

.sequence-key-reuse {
  background: var(--sequence-reuse);
}

@media (min-width: 760px) {
  .sequence-grid,
  .sequence-foundations {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }

  .sequence-card {
    padding: 20px;
  }

  .expansion-sequence figcaption strong {
    margin-left: auto;
  }
}

@media (min-width: 1200px) {
  .sequence-foundations {
    grid-template-columns: repeat(4, minmax(0, 1fr));
  }
}

@media (min-width: 1440px) {
  .sequence-grid {
    grid-template-columns: repeat(4, minmax(0, 1fr));
  }
}