.ab-frontier-intro,
.ef-lesson,
.ef-app {
  max-width: 76rem;
  margin-inline: auto;
}

.ef-lesson > h2:first-child {
  margin-top: 2.8rem;
}

.ef-lesson p,
.ef-lesson > ul,
.ef-lesson > ol {
  max-width: 52rem;
}

.ef-steps {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 1rem;
  margin: 1.8rem 0;
}

.ef-step {
  padding: 1.25rem;
  border-top: 2px solid var(--ab-gold);
  background: rgba(255, 253, 249, 0.65);
}

.ef-step__number {
  color: var(--ab-gold-text);
  font-family: var(--ab-mono);
  font-size: 0.72rem;
}

.ef-step h3 {
  margin: 0.45rem 0 0.65rem;
  font-size: 1rem;
}

.ef-step p {
  margin-bottom: 0;
  color: var(--ab-warm-grey);
  font-size: 0.9rem;
  line-height: 1.6;
}

.ef-reading-note {
  max-width: 52rem;
  margin: 1.5rem 0 3.2rem;
  padding: 1rem 1.2rem;
  border-left: 3px solid var(--ab-gold);
  background: rgba(176, 138, 74, 0.08);
}

.ef-reading-note p {
  margin: 0;
}

.ef-app {
  --ef-blue: var(--ab-navy);
  --ef-gold: var(--ab-gold);
  --ef-paper: var(--ab-paper);
  --ef-rule: var(--ab-rule-strong);
  margin-block: 2.5rem 3rem;
  color: var(--ab-ink);
}

.ef-loading {
  padding: 2rem;
  border: 1px solid var(--ef-rule);
  background: var(--ef-paper);
}

.ef-layout {
  display: grid;
  grid-template-columns: minmax(16rem, 21rem) minmax(0, 1fr);
  gap: clamp(1.25rem, 3vw, 2.5rem);
  align-items: start;
}

.ef-panel,
.ef-chart-panel {
  border: 1px solid var(--ef-rule);
  background: var(--ef-paper);
  box-shadow: var(--ab-shadow);
}

.ef-panel,
.ef-chart-panel {
  padding: 1.4rem;
}

.ef-panel h2,
.ef-chart-panel h2 {
  margin: 0;
  font-family: var(--ab-sans);
  font-size: 1rem;
  font-weight: 650;
  letter-spacing: 0;
}

.ef-control {
  margin-top: 1.5rem;
}

.ef-control__label {
  display: flex;
  gap: 1rem;
  align-items: baseline;
  justify-content: space-between;
  margin-bottom: 0.45rem;
  font-size: 0.88rem;
  font-weight: 650;
}

.ef-control output,
.ef-metric dd,
.ef-weight-table td {
  font-family: var(--ab-mono);
  font-variant-numeric: tabular-nums;
}

.ef-control input[type="range"] {
  width: 100%;
  accent-color: var(--ef-blue);
}

.ef-toggle {
  display: flex;
  gap: 0.65rem;
  align-items: flex-start;
  font-size: 0.88rem;
  line-height: 1.45;
}

.ef-toggle input {
  margin-top: 0.28rem;
  accent-color: var(--ef-blue);
}

.ef-metrics {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 0.75rem;
  margin: 1.4rem 0;
}

.ef-metric {
  margin: 0;
  padding-top: 0.7rem;
  border-top: 1px solid var(--ab-rule);
}

.ef-metric dt {
  color: var(--ab-muted);
  font-size: 0.72rem;
  letter-spacing: 0.06em;
  text-transform: uppercase;
}

.ef-metric dd {
  margin: 0.12rem 0 0;
  color: var(--ef-blue);
  font-size: 1.05rem;
}

.ef-weight-table {
  width: 100%;
  margin: 0;
  border-collapse: collapse;
  font-size: 0.85rem;
}

.ef-weight-table th,
.ef-weight-table td {
  padding: 0.5rem 0;
  border-bottom: 1px solid var(--ab-rule);
}

.ef-weight-table th {
  color: var(--ab-muted);
  font-size: 0.7rem;
  letter-spacing: 0.06em;
  text-align: left;
  text-transform: uppercase;
}

.ef-weight-table th:last-child,
.ef-weight-table td:last-child {
  text-align: right;
}

.ef-chart-panel {
  min-width: 0;
}

.ef-chart-head {
  display: flex;
  flex-wrap: wrap;
  gap: 0.8rem 1.5rem;
  align-items: center;
  justify-content: space-between;
  margin-bottom: 1rem;
}

.ef-legend {
  display: flex;
  flex-wrap: wrap;
  gap: 0.55rem 1rem;
  color: var(--ab-muted);
  font-size: 0.75rem;
}

.ef-legend span {
  display: inline-flex;
  gap: 0.42rem;
  align-items: center;
}

.ef-legend i {
  display: inline-block;
  width: 0.72rem;
  height: 0.72rem;
  background: var(--ef-blue);
  border-radius: 50%;
}

.ef-legend .ef-legend__line {
  width: 1.2rem;
  height: 0.18rem;
  background: var(--ef-gold);
  border-radius: 0;
}

.ef-legend .ef-legend__line--inefficient {
  height: 0;
  background: transparent;
  border-top: 2px dashed var(--ab-muted);
}

.ef-legend .ef-legend__selected {
  background: var(--ef-gold);
  box-shadow: 0 0 0 3px rgba(176, 138, 74, 0.2);
}

.ef-chart {
  width: 100%;
  min-height: 30rem;
}

.ef-chart svg {
  display: block;
  width: 100%;
  height: auto;
  overflow: visible;
}

.ef-grid {
  stroke: var(--ab-rule);
  stroke-width: 1;
}

.ef-frame {
  stroke: var(--ab-rule-strong);
  stroke-width: 1;
}

.ef-axis-label,
.ef-tick,
.ef-point-label {
  fill: var(--ab-warm-grey);
  font-family: var(--ab-sans);
  font-size: 12px;
}

.ef-point-label {
  fill: var(--ab-ink);
  font-weight: 650;
}

.ef-frontier-line {
  fill: none;
  stroke: var(--ef-gold);
  stroke-width: 3;
}

.ef-inefficient-line {
  fill: none;
  stroke: var(--ab-muted);
  stroke-width: 2;
  stroke-dasharray: 6 6;
  opacity: 0.72;
}

.ef-minimum-point {
  fill: var(--ef-paper);
  stroke: var(--ef-gold);
  stroke-width: 3;
}

.ef-minimum-label {
  font-size: 11px;
  font-weight: 500;
}

.ef-asset-point {
  fill: var(--ef-blue);
}

.ef-selected-point {
  fill: var(--ef-gold);
  stroke: var(--ef-paper);
  stroke-width: 3;
}

.ef-status {
  min-height: 1.6rem;
  margin: 0.9rem 0 0;
  color: var(--ab-warm-grey);
  font-size: 0.8rem;
}

.ef-method-note {
  max-width: 76rem;
  margin-inline: auto;
}

.ab-disclosure {
  max-width: 52rem;
  margin: 2rem 0;
}

.ab-disclosure summary {
  padding: 1rem 0;
  color: var(--ab-navy);
  cursor: pointer;
  font-weight: 650;
}

.ab-disclosure__body {
  padding-bottom: 1rem;
}

@media (max-width: 860px) {
  .ef-steps,
  .ef-layout {
    grid-template-columns: 1fr;
  }

  .ef-chart {
    min-height: 24rem;
  }
}

@media (max-width: 520px) {
  .ef-panel,
  .ef-chart-panel {
    padding: 1rem;
  }

  .ef-chart {
    min-height: 20rem;
  }
}