/* Interactive arithmetic-library surfaces.  Everything is scoped with pa-. */
:root {
  --pa-ink: #172033;
  --pa-muted: #5d6880;
  --pa-panel: #f7f9fc;
  --pa-panel-strong: #eef3f9;
  --pa-border: #d8e0ec;
  --pa-accent: #3157d5;
  --pa-accent-soft: #e8edff;
  --pa-success: #157347;
  --pa-success-soft: #e5f5ed;
  --pa-warning: #925d00;
  --pa-warning-soft: #fff2cf;
  --pa-shadow: 0 12px 34px rgba(23, 32, 51, 0.09);
  --pa-radius: 0.9rem;
}

html[data-theme="dark"] {
  --pa-ink: #eef3ff;
  --pa-muted: #aebbd0;
  --pa-panel: #182234;
  --pa-panel-strong: #202d42;
  --pa-border: #35445d;
  --pa-accent: #9bb1ff;
  --pa-accent-soft: #293659;
  --pa-success: #7dd9ac;
  --pa-success-soft: #173b30;
  --pa-warning: #ffd27c;
  --pa-warning-soft: #443617;
  --pa-shadow: 0 14px 38px rgba(0, 0, 0, 0.24);
}

.pa-atlas-hero,
.pa-dashboard-metrics {
  display: grid;
  grid-template-columns: repeat(4, minmax(0, 1fr));
  gap: 0.75rem;
  margin: 1.2rem 0 1.5rem;
}

.pa-atlas-hero > div,
.pa-dashboard-metrics > div {
  display: flex;
  min-height: 6rem;
  flex-direction: column;
  justify-content: center;
  padding: 1rem;
  border: 1px solid var(--pa-border);
  border-radius: var(--pa-radius);
  background: linear-gradient(145deg, var(--pa-panel), var(--pa-panel-strong));
  box-shadow: var(--pa-shadow);
}

.pa-atlas-hero strong,
.pa-dashboard-metrics strong {
  color: var(--pa-accent);
  font-size: clamp(1.35rem, 3vw, 2rem);
  line-height: 1;
}

.pa-atlas-hero span,
.pa-dashboard-metrics span {
  margin-top: 0.45rem;
  color: var(--pa-muted);
  font-size: 0.78rem;
  line-height: 1.25;
  text-transform: uppercase;
  letter-spacing: 0.05em;
}

.pa-noscript {
  padding: 0.8rem 1rem;
  border-left: 0.25rem solid var(--pa-warning);
  background: var(--pa-warning-soft);
}

.pa-atlas-controls {
  display: grid;
  grid-template-columns: minmax(15rem, 2fr) minmax(10rem, 1fr) minmax(10rem, 1fr) auto;
  gap: 0.75rem;
  align-items: end;
  margin: 1rem 0;
  padding: 1rem;
  border: 1px solid var(--pa-border);
  border-radius: var(--pa-radius);
  background: var(--pa-panel);
}

.pa-atlas-controls label,
.pa-focus-heading label {
  display: flex;
  flex-direction: column;
  gap: 0.3rem;
  color: var(--pa-muted);
  font-size: 0.76rem;
  font-weight: 700;
  letter-spacing: 0.035em;
  text-transform: uppercase;
}

.pa-atlas-controls input,
.pa-atlas-controls select,
.pa-focus-heading select,
.pa-atlas-controls button {
  min-height: 2.55rem;
  padding: 0.52rem 0.7rem;
  border: 1px solid var(--pa-border);
  border-radius: 0.55rem;
  background: var(--pa-panel-strong);
  color: var(--pa-ink);
  font: inherit;
  font-size: 0.88rem;
  letter-spacing: normal;
  text-transform: none;
}

.pa-atlas-controls button,
.pa-copy-button,
.pa-route-reset {
  cursor: pointer;
}

.pa-atlas-controls button:hover,
.pa-copy-button:hover,
.pa-route-reset:hover {
  border-color: var(--pa-accent);
  color: var(--pa-accent);
}

.pa-atlas-controls output {
  grid-column: 1 / -1;
  color: var(--pa-muted);
  font-size: 0.86rem;
}

.pa-focus-panel {
  margin: 1.35rem 0 1.6rem;
  padding: 1.1rem;
  overflow: hidden;
  border: 1px solid var(--pa-border);
  border-radius: var(--pa-radius);
  background: radial-gradient(circle at top right, var(--pa-accent-soft), var(--pa-panel) 60%);
  box-shadow: var(--pa-shadow);
}

.pa-focus-heading {
  display: grid;
  grid-template-columns: 1fr minmax(15rem, 1.25fr) minmax(8rem, 0.55fr);
  gap: 1rem;
  align-items: end;
}

.pa-focus-heading h2 {
  margin: 0;
}

.pa-eyebrow {
  color: var(--pa-accent);
  font-size: 0.72rem;
  font-weight: 800;
  letter-spacing: 0.11em;
  text-transform: uppercase;
}

.pa-focus-graph {
  display: grid;
  grid-template-columns: minmax(0, 1fr) auto minmax(0, 1fr) auto minmax(0, 1fr);
  gap: 0.65rem;
  align-items: stretch;
  margin-top: 1rem;
}

.pa-focus-column,
.pa-focus-current {
  min-width: 0;
  padding: 0.85rem;
  border: 1px solid var(--pa-border);
  border-radius: 0.7rem;
  background: var(--pa-panel);
}

.pa-focus-current {
  display: flex;
  flex-direction: column;
  justify-content: center;
  border-color: var(--pa-accent);
  background: var(--pa-accent-soft);
  text-align: center;
}

.pa-focus-column h3,
.pa-focus-current h3 {
  margin: 0 0 0.55rem;
  font-size: 0.83rem;
  letter-spacing: 0.04em;
  text-transform: uppercase;
}

.pa-focus-arrow {
  display: flex;
  align-items: center;
  color: var(--pa-accent);
  font-size: 1.35rem;
  font-weight: 800;
}

.pa-focus-node {
  display: block;
  width: 100%;
  margin: 0.35rem 0;
  padding: 0.42rem 0.5rem;
  overflow-wrap: anywhere;
  border: 1px solid var(--pa-border);
  border-radius: 0.45rem;
  background: var(--pa-panel-strong);
  color: var(--pa-accent);
  text-align: left;
  text-decoration: none;
}

.pa-focus-node:hover {
  border-color: var(--pa-accent);
  text-decoration: none;
}

.pa-hop-distance {
  display: block;
  margin-top: 0.15rem;
  color: var(--pa-muted);
  font-size: 0.68rem;
}

.pa-atlas-list {
  display: grid;
  gap: 0.72rem;
}

.pa-theorem-card {
  scroll-margin-top: 1rem;
  border: 1px solid var(--pa-border);
  border-radius: 0.72rem;
  background: var(--pa-panel);
}

.pa-theorem-card.pa-selected {
  border-color: var(--pa-accent);
  box-shadow: 0 0 0 0.18rem var(--pa-accent-soft);
}

.pa-theorem-card[hidden] {
  display: none;
}

.pa-theorem-card > details > summary {
  display: flex;
  gap: 0.65rem;
  align-items: center;
  padding: 0.85rem 0.95rem;
  cursor: pointer;
  list-style: none;
}

.pa-theorem-card > details > summary::-webkit-details-marker {
  display: none;
}

.pa-theorem-card > details > summary::before {
  content: "＋";
  flex: 0 0 auto;
  color: var(--pa-accent);
  font-weight: 800;
}

.pa-theorem-card > details[open] > summary::before {
  content: "−";
}

.pa-card-title {
  display: flex;
  min-width: 0;
  flex: 1 1 auto;
  flex-direction: column;
  gap: 0.15rem;
}

.pa-card-title code {
  color: var(--pa-accent);
  overflow-wrap: anywhere;
}

.pa-card-title span {
  color: var(--pa-muted);
  font-size: 0.84rem;
}

.pa-badge {
  display: inline-flex;
  align-items: center;
  min-height: 1.55rem;
  padding: 0.18rem 0.5rem;
  border-radius: 999px;
  background: var(--pa-panel-strong);
  color: var(--pa-muted);
  font-size: 0.67rem;
  font-weight: 800;
  line-height: 1.1;
  text-align: center;
  text-transform: uppercase;
  letter-spacing: 0.035em;
}

.pa-status-checked {
  background: var(--pa-success-soft);
  color: var(--pa-success);
}

.pa-status-blocked {
  background: var(--pa-warning-soft);
  color: var(--pa-warning);
}

.pa-card-body {
  padding: 0 1rem 1rem;
  border-top: 1px solid var(--pa-border);
}

.pa-card-summary {
  color: var(--pa-ink);
  font-size: 1rem;
}

.pa-relation-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1rem;
  margin: 0.9rem 0;
}

.pa-chip-row {
  display: flex;
  flex-wrap: wrap;
  gap: 0.35rem;
  margin-top: 0.35rem;
}

.pa-theorem-chip {
  padding: 0.22rem 0.4rem;
  border: 1px solid var(--pa-border);
  border-radius: 0.4rem;
  background: var(--pa-panel-strong);
  text-decoration: none;
}

.pa-theorem-chip:hover {
  border-color: var(--pa-accent);
  text-decoration: none;
}

.pa-empty-relation {
  color: var(--pa-muted);
  font-style: italic;
}

.pa-proof-dropdown {
  position: relative;
  margin: 0.7rem 0;
  padding: 0.55rem 0.7rem;
  border: 1px solid var(--pa-border);
  border-radius: 0.55rem;
  background: var(--pa-panel-strong);
}

.pa-proof-dropdown > summary {
  padding-right: 6.5rem;
  cursor: pointer;
  color: var(--pa-accent);
  font-weight: 700;
}

.pa-proof-dropdown pre {
  max-height: 28rem;
  margin: 0.65rem 0 0;
  overflow: auto;
  white-space: pre-wrap;
  overflow-wrap: anywhere;
}

.pa-copy-button {
  float: right;
  margin-top: 0.5rem;
  padding: 0.28rem 0.48rem;
  border: 1px solid var(--pa-border);
  border-radius: 0.4rem;
  background: var(--pa-panel);
  color: var(--pa-muted);
  font-size: 0.74rem;
}

.pa-proof-receipt {
  display: grid;
  grid-template-columns: repeat(4, minmax(0, 1fr));
  gap: 0.5rem;
  margin: 0.9rem 0;
}

.pa-proof-receipt > div {
  min-width: 0;
  padding: 0.55rem;
  border-radius: 0.5rem;
  background: var(--pa-panel-strong);
}

.pa-proof-receipt dt {
  color: var(--pa-muted);
  font-size: 0.68rem;
  font-weight: 800;
  text-transform: uppercase;
}

.pa-proof-receipt dd {
  margin: 0.25rem 0 0;
  overflow-wrap: anywhere;
  color: var(--pa-ink);
}

.pa-card-links {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem 0.85rem;
  margin-top: 0.85rem;
  padding-top: 0.75rem;
  border-top: 1px solid var(--pa-border);
  font-size: 0.85rem;
}

.pa-deployment-note {
  display: inline-flex;
  align-items: center;
  gap: 0.3rem;
  color: var(--pa-muted);
}

.pa-roadmap {
  display: grid;
  grid-template-columns: repeat(5, minmax(0, 1fr));
  gap: 0.65rem;
  margin: 1.2rem 0 1.6rem;
}

.pa-roadmap a,
.pa-roadmap .pa-stage {
  display: flex;
  min-height: 6.2rem;
  flex-direction: column;
  justify-content: space-between;
  padding: 0.85rem;
  border: 1px solid var(--pa-border);
  border-radius: 0.75rem;
  background: linear-gradient(145deg, var(--pa-panel), var(--pa-panel-strong));
  box-shadow: var(--pa-shadow);
  color: var(--pa-ink);
  text-decoration: none;
}

.pa-roadmap a:hover {
  border-color: var(--pa-accent);
  transform: translateY(-1px);
  text-decoration: none;
}

.pa-roadmap strong {
  color: var(--pa-accent);
}

.pa-roadmap small {
  color: var(--pa-muted);
}

.pa-flow-bridge {
  display: grid;
  grid-template-columns: 1fr auto 1fr auto 1fr;
  gap: 0.6rem;
  align-items: center;
  margin: 1rem 0;
  padding: 1rem;
  border: 1px solid var(--pa-border);
  border-radius: var(--pa-radius);
  background: var(--pa-panel);
}

.pa-flow-node {
  padding: 0.75rem;
  border-radius: 0.65rem;
  background: var(--pa-panel-strong);
  text-align: center;
}

.pa-flow-arrow {
  color: var(--pa-accent);
  font-size: 1.4rem;
  font-weight: 800;
}

.pa-sequence-diagram {
  display: grid;
  grid-template-columns: minmax(7rem, 1.2fr) repeat(4, minmax(5rem, 1fr));
  gap: 0.4rem;
  margin: 1rem 0;
  padding: 1rem;
  overflow-x: auto;
  border: 1px solid var(--pa-border);
  border-radius: var(--pa-radius);
  background: var(--pa-panel);
}

.pa-sequence-label,
.pa-sequence-cell {
  display: flex;
  min-height: 3.4rem;
  align-items: center;
  justify-content: center;
  padding: 0.5rem;
  border-radius: 0.5rem;
  background: var(--pa-panel-strong);
  text-align: center;
}

.pa-sequence-label {
  justify-content: flex-start;
  color: var(--pa-accent);
  font-weight: 800;
}

.pa-learning-route {
  display: grid;
  gap: 0.45rem;
  margin: 1rem 0;
  padding: 1rem;
  border: 1px solid var(--pa-border);
  border-radius: var(--pa-radius);
  background: var(--pa-panel);
}

.pa-learning-route label {
  display: flex;
  gap: 0.65rem;
  align-items: flex-start;
  padding: 0.55rem;
  border-radius: 0.45rem;
}

.pa-learning-route label:hover {
  background: var(--pa-panel-strong);
}

.pa-learning-route input {
  margin-top: 0.25rem;
}

.pa-route-reset {
  justify-self: start;
  padding: 0.35rem 0.6rem;
  border: 1px solid var(--pa-border);
  border-radius: 0.45rem;
  background: var(--pa-panel-strong);
  color: var(--pa-muted);
}

.pa-atlas :focus-visible,
.pa-roadmap :focus-visible,
.pa-learning-route :focus-visible {
  outline: 0.2rem solid var(--pa-accent);
  outline-offset: 0.15rem;
}

@media (max-width: 900px) {
  .pa-atlas-hero,
  .pa-dashboard-metrics,
  .pa-proof-receipt {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }

  .pa-atlas-controls,
  .pa-focus-heading,
  .pa-relation-grid {
    grid-template-columns: 1fr;
  }

  .pa-roadmap {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }

  .pa-focus-graph,
  .pa-flow-bridge {
    grid-template-columns: 1fr;
  }

  .pa-focus-arrow,
  .pa-flow-arrow {
    justify-content: center;
    transform: rotate(90deg);
  }
}

@media (max-width: 540px) {
  .pa-atlas-hero,
  .pa-dashboard-metrics,
  .pa-proof-receipt,
  .pa-roadmap {
    grid-template-columns: 1fr;
  }

  .pa-theorem-card > details > summary {
    flex-wrap: wrap;
  }

  .pa-card-title {
    flex-basis: 100%;
  }
}

@media print {
  .pa-atlas-controls,
  .pa-focus-panel,
  .pa-copy-button,
  .pa-route-reset {
    display: none !important;
  }

  .pa-theorem-card[hidden] {
    display: block;
  }

  .pa-theorem-card {
    break-inside: avoid;
  }

  .pa-theorem-card details:not([open]) > :not(summary) {
    display: block !important;
  }
}

@media (prefers-reduced-motion: reduce) {
  .pa-roadmap a {
    transition: none;
  }
}