/* Architecture page — layout rail, diagrams, flows, machines, ladder. */

.arch-hero {
  position: relative;
  overflow: clip;
}
.arch-hero .hero__content {
  padding: clamp(72px, 10vh, 120px) var(--space-lg) clamp(56px, 8vh, 96px);
}
.arch-hero h1 { font-size: clamp(2.3rem, 1.4rem + 3.4vw, 3.8rem); }
.arch-hero .hero__lede { max-width: 58ch; }

/* ---------- Page grid with rail ---------- */

.arch-layout {
  max-width: 1320px;
  margin: 0 auto;
  padding-inline: var(--space-lg);
  display: grid;
  grid-template-columns: 216px minmax(0, 1fr);
  gap: clamp(var(--space-xl), 4vw, var(--space-4xl));
  align-items: start;
}

.rail {
  position: sticky;
  top: 96px;
  padding-block: var(--space-2xl);
  font-family: var(--font-display);
  font-size: 0.98rem;
}
.rail ol { list-style: none; margin: 0; padding: 0; display: flex; flex-direction: column; }
.rail a {
  display: block;
  padding: 7px 0 7px var(--space-md);
  border-left: 2px solid var(--line);
  text-decoration: none;
  color: var(--ink-muted);
  transition: color 150ms var(--ease-out), border-color 150ms var(--ease-out);
}
.rail a:hover { color: var(--ink); }
.rail a.is-active {
  color: var(--positron);
  border-left-color: var(--positron);
  font-weight: 600;
}

.arch-main { min-width: 0; padding-block: var(--space-2xl); }
.arch-section { padding-block: clamp(var(--space-2xl), 6vw, var(--space-4xl)); }
.arch-section + .arch-section { border-top: 1px solid var(--line); }
.arch-section > h2 { max-width: 24ch; }
.arch-section .lede { font-size: 1.15rem; color: var(--ink-muted); max-width: 62ch; }

.src {
  font-family: var(--font-code);
  font-weight: 500;
  font-size: 0.8rem;
  letter-spacing: 0.02em;
  color: var(--ink-muted);
}
.src a { text-decoration-color: color-mix(in oklch, var(--positron), transparent 55%); }

/* ---------- Diagram panels ---------- */

.diagram {
  background: var(--deep);
  color: var(--deep-ink);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-deep);
  padding: clamp(var(--space-sm), 2.5vw, var(--space-lg));
  margin-block: var(--space-lg);
  overflow-x: auto;
}
.diagram svg {
  display: block;
  width: 100%;
  min-width: 620px;
  height: auto;
}
.diagram--fit svg { min-width: 0; }
.diagram figcaption,
.diagram-caption {
  font-size: 0.92rem;
  color: var(--ink-muted);
  padding-top: var(--space-sm);
  max-width: var(--measure);
}
figure.diagram-wrap { margin: var(--space-lg) 0; }
figure.diagram-wrap .diagram { margin-block: 0; }
figure.diagram-wrap figcaption { font-size: 0.92rem; color: var(--ink-muted); padding-top: var(--space-sm); }

/* SVG vocabulary (matches site.css deep tokens) */
.dg-box { fill: oklch(21% 0.038 268); stroke: oklch(36% 0.05 268); }
.dg-box--kernel { fill: oklch(24% 0.05 285); stroke: oklch(42% 0.07 290); }
.dg-box--ext { fill: none; stroke: oklch(36% 0.05 268); stroke-dasharray: 4 5; }
.dg-chip { fill: oklch(27% 0.045 268); stroke: oklch(40% 0.05 268); }
.dg-label { font: 500 14px var(--font-code); fill: oklch(94% 0.012 262); }
.dg-label--lg { font: 600 16px var(--font-display); fill: oklch(94% 0.012 262); }
.dg-sub { font: 500 11.5px var(--font-code); fill: oklch(76% 0.028 262); }
.dg-edge { stroke: oklch(48% 0.05 268); stroke-width: 1.6; fill: none; }
.dg-edge--logs { stroke: oklch(60% 0.13 262); }
.dg-edge--traces { stroke: oklch(62% 0.13 342); }
.dg-edge--soft { stroke: oklch(40% 0.05 268); }
.dg-accent-logs { fill: oklch(72% 0.14 262); }
.dg-accent-traces { fill: oklch(74% 0.13 342); }
.dg-accent-verify { fill: oklch(76% 0.115 166); }
.dg-accent-warn { fill: oklch(78% 0.11 76); }

g[data-mod] { cursor: default; }
g[data-mod] rect { transition: stroke 150ms var(--ease-out), fill 150ms var(--ease-out); }
g[data-mod]:hover > rect { stroke: oklch(72% 0.14 262); }

/* ---------- Module map accordion ---------- */

.modmap { display: flex; flex-direction: column; gap: var(--space-2xl); margin-top: var(--space-xl); }
.modmap__group h3 {
  display: flex; align-items: baseline; gap: var(--space-sm);
  margin-bottom: var(--space-sm);
}
.modmap__count {
  font: 500 0.8rem var(--font-code);
  color: var(--ink-muted);
}
.mod {
  border-top: 1px solid var(--line);
}
.mod:last-child { border-bottom: 1px solid var(--line); }
.mod summary {
  display: grid;
  grid-template-columns: minmax(180px, 300px) 1fr auto;
  gap: var(--space-md);
  align-items: baseline;
  padding: var(--space-md) var(--space-2xs);
  cursor: pointer;
  list-style: none;
  transition: background-color 150ms var(--ease-out);
}
.mod summary::-webkit-details-marker { display: none; }
.mod summary:hover { background: var(--surface-raised); }
.mod summary b { font-family: var(--font-display); font-weight: 600; font-size: 1.1rem; }
.mod summary .mod__learn { color: var(--ink-muted); font-size: 0.98rem; }
.mod summary::after {
  content: "+";
  font-family: var(--font-code);
  font-size: 1.1rem;
  color: var(--positron);
  transition: transform 200ms var(--ease-out);
}
.mod[open] summary::after { transform: rotate(45deg); }
.mod__body {
  padding: 0 var(--space-2xs) var(--space-lg);
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
  gap: var(--space-lg);
}
.mod__body h4 {
  font: 500 0.78rem var(--font-code);
  letter-spacing: 0.07em;
  text-transform: uppercase;
  color: var(--ink-muted);
  margin-bottom: var(--space-xs);
}
.mod__body p { font-size: 0.98rem; margin: 0; }

/* ---------- Flow tabs ---------- */

.flows { margin-top: var(--space-xl); }
.flows__tabs {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-xs);
  margin-bottom: var(--space-lg);
}
.flows__tabs button {
  font: 600 0.98rem var(--font-display);
  padding: 0.5em 1em;
  border: 1px solid var(--line);
  border-radius: 999px;
  background: transparent;
  color: var(--ink-muted);
  cursor: pointer;
  transition: color 150ms var(--ease-out), border-color 150ms var(--ease-out), background-color 150ms var(--ease-out);
}
.flows__tabs button:hover { border-color: var(--positron); color: var(--ink); }
.flows__tabs button[aria-selected="true"] {
  background: var(--positron);
  border-color: var(--positron);
  color: oklch(98% 0.008 262);
}
.flow-panel[hidden] { display: none; }
.flow-panel {
  display: grid;
  grid-template-columns: minmax(300px, 5fr) minmax(280px, 4fr);
  gap: clamp(var(--space-lg), 4vw, var(--space-3xl));
  align-items: start;
}
.flow-panel--single { grid-template-columns: 1fr; }

.steps { list-style: none; counter-reset: step; margin: 0; padding: 0; max-width: 56ch; }
.steps li {
  counter-increment: step;
  position: relative;
  padding: 0 0 var(--space-md) 52px;
}
.steps li::before {
  content: counter(step, decimal-leading-zero);
  position: absolute;
  left: 0; top: 1px;
  font: 600 0.85rem var(--font-code);
  color: var(--positron);
}
.steps li::after {
  content: "";
  position: absolute;
  left: 14px; top: 26px; bottom: 6px;
  width: 1px;
  background: var(--line);
}
.steps li:last-child::after { display: none; }
.flow-panel .guarantee {
  border: 1px solid var(--line);
  border-radius: var(--radius-md);
  background: var(--surface-raised);
  padding: var(--space-md) var(--space-lg);
  font-size: 0.98rem;
  max-width: 56ch;
}
.flow-panel .guarantee b { font-family: var(--font-display); }

/* ---------- State machines ---------- */

.machines {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: var(--space-lg);
  margin-top: var(--space-lg);
}

/* ---------- Crate graph ---------- */

.crate-note { font-size: 0.95rem; color: var(--ink-muted); max-width: var(--measure); }
g[data-crate] { cursor: pointer; }
g[data-crate] rect { transition: stroke 150ms var(--ease-out), fill 150ms var(--ease-out); }
g[data-crate].is-dim { opacity: 0.28; }
g[data-crate].is-focus > rect { stroke: oklch(72% 0.14 262); fill: oklch(27% 0.06 275); }
path[data-dep] { transition: opacity 150ms var(--ease-out), stroke 150ms var(--ease-out); }
path[data-dep].is-dim { opacity: 0.08; }
path[data-dep].is-focus { stroke: oklch(72% 0.14 262); opacity: 1; }

/* ---------- Seams table ---------- */

.table-wrap { overflow-x: auto; margin-top: var(--space-lg); border: 1px solid var(--line); border-radius: var(--radius-md); }
.seams { border-collapse: collapse; width: 100%; min-width: 720px; font-size: 0.95rem; }
.seams th, .seams td { text-align: left; padding: var(--space-sm) var(--space-md); vertical-align: top; }
.seams thead th {
  font: 500 0.78rem var(--font-code);
  letter-spacing: 0.06em;
  text-transform: uppercase;
  color: var(--ink-muted);
  border-bottom: 1px solid var(--line);
  background: var(--surface-raised);
}
.seams tbody tr + tr td { border-top: 1px solid var(--line); }
.seams td:first-child { font-family: var(--font-display); font-weight: 600; white-space: nowrap; }
.seams .mono { font-size: 0.85rem; color: var(--ink-muted); }

/* ---------- Invariant families ---------- */

.invariants {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
  gap: 0 var(--space-2xl);
  margin-top: var(--space-lg);
}
.invariants dl { margin: 0; }
.invariants .inv {
  display: grid;
  grid-template-columns: 96px 1fr;
  gap: var(--space-md);
  padding-block: var(--space-sm);
  border-top: 1px solid var(--line);
}
.invariants dt { font: 600 0.9rem var(--font-code); color: var(--positron); }
.invariants dd { margin: 0; font-size: 0.95rem; color: var(--ink-muted); }

/* ---------- Milestone ladder ---------- */

.ladder { list-style: none; margin: var(--space-xl) 0 0; padding: 0; max-width: 760px; }
.ladder li {
  position: relative;
  display: grid;
  grid-template-columns: 72px 1fr;
  gap: var(--space-lg);
  padding-bottom: var(--space-xl);
}
.ladder li::before {
  content: "";
  position: absolute;
  left: 26px; top: 40px; bottom: 4px;
  width: 2px;
  background: var(--line);
}
.ladder li:last-child::before { display: none; }
.ladder .m {
  width: 52px; height: 52px;
  border-radius: 50%;
  display: grid;
  place-items: center;
  font: 600 1rem var(--font-code);
  background: var(--deep);
  color: var(--positron-bright);
  border: 2px solid var(--deep-line);
}
.ladder li[data-now] .m { border-color: var(--positron-bright); }
.ladder h3 { margin-bottom: 2px; font-size: 1.15rem; }
.ladder p { margin: 0; color: var(--ink-muted); font-size: 0.98rem; max-width: 56ch; }
.ladder .now-tag {
  display: inline-block;
  margin-left: var(--space-xs);
  font: 500 0.72rem var(--font-code);
  letter-spacing: 0.06em;
  text-transform: uppercase;
  color: var(--verify);
  border: 1px solid color-mix(in oklch, var(--verify), transparent 55%);
  border-radius: 999px;
  padding: 2px 9px;
  vertical-align: middle;
}

/* ---------- Responsive ---------- */

@media (max-width: 980px) {
  .arch-layout { grid-template-columns: minmax(0, 1fr); }
  .rail { display: none; }
  .flow-panel { grid-template-columns: 1fr; }
  .mod summary { grid-template-columns: 1fr auto; }
  .mod summary .mod__learn { display: none; }
}