:root {
  color-scheme: light dark;
  --paper: #eee6d4;
  --paper-deep: #e3d8c0;
  --ink: #132548;
  --ink-soft: #3f4d65;
  --line: #8d8a80;
  --line-soft: rgba(19, 37, 72, 0.22);
  --panel: rgba(255, 252, 242, 0.54);
  --panel-solid: #f4eddd;
  --accent: #b94f27;
  --accent-soft: rgba(185, 79, 39, 0.12);
  --good: #2f6b57;
  --muted: #77766f;
  --shadow: rgba(19, 37, 72, 0.12);
  --serif: Georgia, "Times New Roman", serif;
  --mono: "Courier New", Courier, monospace;
  --sans: Inter, ui-sans-serif, system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
}

:root[data-theme="dark"] {
  color-scheme: dark;
  --paper: #0e2147;
  --paper-deep: #0a1936;
  --ink: #efe6d3;
  --ink-soft: #c5cadd;
  --line: #8491a9;
  --line-soft: rgba(239, 230, 211, 0.25);
  --panel: rgba(17, 39, 78, 0.68);
  --panel-solid: #132b55;
  --accent: #e47742;
  --accent-soft: rgba(228, 119, 66, 0.13);
  --good: #83c0a7;
  --muted: #8c98ae;
  --shadow: rgba(0, 0, 0, 0.22);
}

@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) {
    color-scheme: dark;
    --paper: #0e2147;
    --paper-deep: #0a1936;
    --ink: #efe6d3;
    --ink-soft: #c5cadd;
    --line: #8491a9;
    --line-soft: rgba(239, 230, 211, 0.25);
    --panel: rgba(17, 39, 78, 0.68);
    --panel-solid: #132b55;
    --accent: #e47742;
    --accent-soft: rgba(228, 119, 66, 0.13);
    --good: #83c0a7;
    --muted: #8c98ae;
    --shadow: rgba(0, 0, 0, 0.22);
  }
}

* {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
  scroll-padding-top: 7.5rem;
}

body {
  margin: 0;
  min-width: 320px;
  background:
    repeating-linear-gradient(0deg, transparent 0 4px, rgba(75, 61, 42, 0.018) 4px 5px),
    var(--paper);
  color: var(--ink);
  font-family: var(--serif);
  font-size: 18px;
  line-height: 1.62;
}

a {
  color: inherit;
  text-decoration-color: var(--accent);
  text-underline-offset: 0.18em;
}

a:hover {
  color: var(--accent);
}

button,
input {
  font: inherit;
}

button {
  color: inherit;
}

sup,
sub {
  line-height: 0;
}

code {
  font-family: var(--mono);
  font-size: 0.9em;
}

.skip-link {
  position: fixed;
  top: -5rem;
  left: 1rem;
  z-index: 100;
  padding: 0.5rem 0.75rem;
  background: var(--paper);
  border: 1px solid var(--ink);
}

.skip-link:focus {
  top: 1rem;
}

.site-header,
.section-nav,
main,
footer {
  width: min(1180px, calc(100% - 2rem));
  margin-inline: auto;
}

.site-header {
  min-height: 4.6rem;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
  border-bottom: 3px double var(--line);
}

.site-identity {
  display: flex;
  align-items: baseline;
  gap: 0.8rem;
}

.site-identity a {
  font-family: var(--serif);
  font-size: 1.16rem;
  font-weight: 700;
  text-decoration: none;
}

.site-identity span,
.theme-control button,
.section-nav,
.eyebrow,
.label,
figcaption,
.two-culls > div > span,
.storage-summary > span,
.packing-stat span,
.state-example span,
.walk-toolbar span,
.walk-readout span,
.founder-readout span,
.representation-tradeoff span,
.three-findings span,
.reference-grid small,
footer,
.fine-print {
  font-family: var(--mono);
}

.site-identity span {
  color: var(--ink-soft);
  font-size: 0.84rem;
}

.theme-control,
.segmented {
  display: inline-flex;
  flex-wrap: wrap;
}

.theme-control button,
.segmented button {
  min-height: 2.15rem;
  padding: 0.32rem 0.65rem;
  border: 1px solid var(--line);
  border-right-width: 0;
  border-radius: 0;
  background: transparent;
  cursor: pointer;
  font-family: var(--mono);
  font-size: 0.78rem;
}

.theme-control button:last-child,
.segmented button:last-child {
  border-right-width: 1px;
}

.theme-control button[aria-pressed="true"],
.segmented button[aria-pressed="true"] {
  background: var(--ink);
  color: var(--paper);
  box-shadow: inset 0 -3px 0 var(--accent);
}

.theme-control button:focus-visible,
.segmented button:focus-visible,
.walk-node:focus-visible,
.trie-node:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: 2px;
}

.section-nav {
  position: sticky;
  top: 0;
  z-index: 20;
  display: grid;
  grid-template-columns: repeat(6, 1fr);
  background: var(--paper);
  border-bottom: 1px solid var(--line);
  box-shadow: 0 3px 8px var(--shadow);
}

.section-nav a {
  padding: 0.62rem 0.5rem;
  border-right: 1px solid var(--line-soft);
  color: var(--ink-soft);
  font-size: 0.78rem;
  text-align: center;
  text-decoration: none;
}

.section-nav a:last-child {
  border-right: 0;
}

.section-nav a span {
  margin-right: 0.35rem;
  color: var(--accent);
}

.section-nav a[aria-current="location"] {
  background: var(--accent-soft);
  color: var(--ink);
  box-shadow: inset 0 -2px 0 var(--accent);
}

main {
  border-inline: 1px solid var(--line-soft);
}

.hero,
.chapter {
  padding: 4.6rem clamp(1.2rem, 4vw, 3.5rem);
}

.hero {
  padding-top: 5.2rem;
}

.eyebrow,
.label {
  margin: 0 0 0.75rem;
  color: var(--accent);
  font-size: 0.77rem;
  font-weight: 700;
  letter-spacing: 0.08em;
  text-transform: uppercase;
}

h1,
h2,
h3 {
  margin-top: 0;
  font-weight: 500;
  line-height: 1.13;
}

h1 {
  max-width: 850px;
  margin-bottom: 1.4rem;
  font-size: clamp(2.1rem, 4.2vw, 3.25rem);
  letter-spacing: -0.025em;
}

h2 {
  margin-bottom: 0.8rem;
  font-size: clamp(1.75rem, 2.8vw, 2.3rem);
}

h3 {
  margin-bottom: 0.65rem;
  font-size: clamp(1.25rem, 1.8vw, 1.55rem);
}

p {
  margin: 0 0 1rem;
}

.lede {
  max-width: 830px;
  color: var(--ink-soft);
  font-size: 1.17rem;
}

.definition {
  max-width: 830px;
  margin: 2rem 0 0;
  padding-left: 1rem;
  border-left: 3px solid var(--accent);
}

.project-index {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  margin-top: 3rem;
  border: 1px solid var(--line);
}

.project-index a {
  min-height: 9rem;
  display: grid;
  align-content: start;
  gap: 0.3rem;
  padding: 1.2rem;
  border-right: 1px solid var(--line);
  text-decoration: none;
}

.project-index a:last-child {
  border-right: 0;
}

.project-index span {
  color: var(--accent);
  font-family: var(--mono);
  font-size: 0.8rem;
}

.project-index strong {
  font-size: 1.18rem;
}

.project-index small {
  color: var(--ink-soft);
  font-size: 0.93rem;
  line-height: 1.4;
}

.chapter {
  border-top: 3px double var(--line);
}

.chapter-header {
  display: grid;
  grid-template-columns: 9.5rem minmax(0, 1.1fr) minmax(18rem, 0.9fr);
  gap: 1.5rem 2rem;
  align-items: start;
  margin-bottom: 3.2rem;
}

.chapter-header > div {
  display: flex;
  flex-direction: column;
  gap: 0.15rem;
}

.chapter-header > div span {
  color: var(--accent);
  font-family: var(--mono);
  font-size: 1.25rem;
}

.chapter-header > div small {
  color: var(--ink-soft);
  font-family: var(--mono);
  font-size: 0.75rem;
  line-height: 1.35;
}

.chapter-header p {
  color: var(--ink-soft);
}

.two-column,
.two-culls,
.conclusions {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
}

.note-block {
  padding: 1.5rem;
  border: 1px solid var(--line);
  background: var(--panel);
}

.note-block + .note-block {
  border-left: 0;
}

.piecewise {
  display: flex;
  align-items: center;
  gap: 1rem;
  margin: 1rem 0 1.25rem;
}

.piecewise > strong {
  font-size: 1.25rem;
}

.piecewise span {
  padding-left: 1rem;
  border-left: 2px solid var(--ink);
}

.equation {
  margin: 1.3rem 0;
  padding: 0.9rem;
  background: var(--accent-soft);
  border-block: 1px solid var(--line-soft);
  font-size: clamp(1.1rem, 2vw, 1.35rem);
  text-align: center;
}

.text-link {
  font-family: var(--mono);
  font-size: 0.8rem;
}

.plate {
  margin: 3.2rem 0;
  border: 1px solid var(--line);
  background: var(--panel);
}

figcaption {
  padding: 0.6rem 0.85rem;
  border-bottom: 3px double var(--line);
  color: var(--accent);
  font-size: 0.78rem;
  font-weight: 700;
  letter-spacing: 0.04em;
  text-transform: uppercase;
}

.pair-grid {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
}

.pair-grid > div {
  min-height: 9.5rem;
  display: flex;
  flex-direction: column;
  justify-content: center;
  gap: 0.5rem;
  padding: 1.3rem;
  border-right: 1px solid var(--line);
}

.pair-grid > div:last-child {
  border-right: 0;
}

.pair-grid span,
.pair-grid small {
  color: var(--ink-soft);
  font-family: var(--mono);
  font-size: 0.79rem;
}

.pair-grid strong {
  font-size: 1.22rem;
}

.accent-cell {
  background: var(--accent-soft);
}

.formula-strip {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  border-top: 1px solid var(--line);
}

.formula-strip > span {
  padding: 0.85rem 1.2rem;
  border-right: 1px solid var(--line);
  font-size: 0.95rem;
  text-align: center;
}

.formula-strip > span:last-child {
  border-right: 0;
}

.two-culls {
  margin-bottom: 3.5rem;
  border: 1px solid var(--line);
}

.two-culls > div {
  padding: 1.3rem;
  border-right: 1px solid var(--line);
}

.two-culls > div:last-child {
  border-right: 0;
}

.two-culls > div > span {
  display: block;
  margin-bottom: 0.45rem;
  color: var(--accent);
  font-size: 0.76rem;
}

.two-culls strong {
  font-size: 1.08rem;
}

.two-culls p {
  margin: 0.6rem 0 0;
  color: var(--ink-soft);
}

.prior-rules {
  display: grid;
  grid-template-columns: 0.8fr 1.6fr;
  gap: 2rem;
  margin: 3.5rem 0;
}

.prior-rules ol {
  margin: 0;
  padding: 0;
  border-top: 1px solid var(--line);
  list-style: none;
}

.prior-rules li {
  display: grid;
  grid-template-columns: 3rem 1fr;
  gap: 1rem;
  padding: 1rem 0;
  border-bottom: 1px solid var(--line);
}

.prior-rules li > b {
  color: var(--accent);
  font-family: var(--mono);
}

.prior-rules li p {
  margin: 0;
}

.reverse-definition,
.length-cull,
.founder-text,
.descent-example,
.machine-context,
.lut-intro {
  display: grid;
  grid-template-columns: minmax(0, 1.1fr) minmax(18rem, 0.9fr);
  gap: 2.4rem;
  align-items: start;
  margin: 3.5rem 0;
}

.formula-box {
  display: grid;
  gap: 0.7rem;
  padding: 1.2rem;
  border: 1px solid var(--line);
  background: var(--accent-soft);
}

.formula-box strong,
.formula-box b {
  font-size: 1.1rem;
}

.formula-box small {
  color: var(--ink-soft);
  font-size: 0.84rem;
}

.walk-toolbar {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  border-bottom: 1px solid var(--line);
}

.walk-toolbar > div,
.walk-toolbar label {
  display: flex;
  flex-direction: column;
  gap: 0.25rem;
  padding: 0.8rem 1rem;
  border-right: 1px solid var(--line);
}

.walk-toolbar > *:last-child {
  border-right: 0;
}

.walk-toolbar span {
  color: var(--ink-soft);
  font-size: 0.75rem;
}

.walk-toolbar input {
  width: 100%;
  accent-color: var(--accent);
}

.walk-canvas {
  position: relative;
  min-width: 760px;
  height: 330px;
  overflow: hidden;
}

.walk-canvas-wrap {
  overflow-x: auto;
  border-bottom: 1px solid var(--line);
}

.walk-svg,
.trie-svg {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
  pointer-events: none;
}

.walk-svg line,
.trie-svg line {
  stroke: var(--line);
  stroke-width: 0.7;
  vector-effect: non-scaling-stroke;
}

.walk-svg line.path {
  stroke: var(--accent);
  stroke-width: 1.6;
}

.walk-svg line.continuation {
  stroke-dasharray: 5 4;
}

.walk-node,
.trie-node {
  position: absolute;
  translate: -50% -50%;
  z-index: 2;
  border: 1px solid var(--line);
  border-radius: 0;
  background: var(--panel-solid);
  cursor: pointer;
}

.walk-node {
  width: 6.7rem;
  min-height: 3.2rem;
  padding: 0.3rem;
}

.walk-node span,
.walk-node strong {
  display: block;
}

.walk-node span {
  color: var(--ink-soft);
  font-family: var(--mono);
  font-size: 0.75rem;
}

.walk-node strong {
  font-size: 0.88rem;
}

.walk-node.path {
  border-color: var(--accent);
}

.walk-node.certified {
  background: var(--accent);
  color: var(--paper);
}

.walk-node[aria-pressed="true"] {
  outline: 3px double var(--accent);
  outline-offset: 3px;
}

.walk-readout {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
}

.walk-readout > div {
  display: grid;
  gap: 0.35rem;
  padding: 1rem;
  border-right: 1px solid var(--line);
}

.walk-readout > div:last-child {
  border-right: 0;
}

.walk-readout span,
.walk-readout small {
  color: var(--ink-soft);
  font-size: 0.76rem;
}

.walk-readout strong {
  display: flex;
  flex-wrap: wrap;
  gap: 0.45rem 1.2rem;
}

.walk-readout .passed {
  background: color-mix(in srgb, var(--good) 13%, transparent);
}

.walk-readout .pass {
  color: var(--good);
}

.walk-readout .fail {
  color: var(--accent);
}

.certificate {
  display: grid;
  grid-template-columns: auto auto auto auto minmax(15rem, 1fr);
  gap: 1rem;
  align-items: center;
  margin: 3.5rem 0;
  padding: 1.1rem 1.3rem;
  border-block: 3px double var(--line);
}

.certificate > span {
  color: var(--accent);
  font-family: var(--mono);
  font-size: 0.78rem;
  text-transform: uppercase;
}

.certificate > strong {
  padding: 0.25rem 0.6rem;
  border: 1px solid var(--accent);
  font-size: 1.2rem;
}

.certificate p {
  margin: 0;
  padding-left: 1rem;
  border-left: 1px solid var(--line);
}

.conclusions {
  border: 1px solid var(--line);
}

.conclusions > div {
  padding: 1.3rem;
  border-right: 1px solid var(--line);
}

.conclusions > div:last-child {
  border-right: 0;
}

.storage-section {
  display: grid;
  grid-template-columns: minmax(0, 1fr) minmax(17rem, 0.65fr);
  gap: 1.5rem 2rem;
  margin-bottom: 4rem;
}

.storage-summary {
  display: flex;
  flex-direction: column;
  justify-content: center;
  gap: 0.45rem;
  padding: 1.3rem;
  border: 1px solid var(--line);
  background: var(--accent-soft);
}

.storage-summary span,
.storage-summary small {
  font-size: 0.78rem;
}

.storage-summary strong {
  font-size: 1.2rem;
}

.storage-bars {
  grid-column: 1 / -1;
  display: grid;
  gap: 0.75rem;
  padding: 1rem;
  border: 1px solid var(--line);
}

.storage-bars > div {
  display: grid;
  grid-template-columns: minmax(13rem, 0.85fr) minmax(10rem, 1.7fr) 6rem;
  gap: 0.7rem;
  align-items: center;
}

.storage-bars span {
  font-size: 0.9rem;
}

.storage-bars i {
  width: var(--size);
  height: 0.8rem;
  display: block;
  background: var(--ink);
  border-right: 5px solid var(--accent);
}

.storage-bars b {
  font-family: var(--mono);
  font-size: 0.78rem;
  text-align: right;
}

.fine-print {
  grid-column: 1 / -1;
  margin: 0;
  color: var(--ink-soft);
  font-size: 0.78rem;
}

.bitmap-opening,
.ternary-intro {
  display: grid;
  grid-template-columns: minmax(0, 1.3fr) minmax(13rem, 0.45fr);
  gap: 2rem;
  align-items: start;
}

.bitmap-opening aside {
  display: flex;
  flex-direction: column;
  gap: 0.25rem;
  padding: 1.2rem;
  border: 1px solid var(--line);
}

.bitmap-opening aside strong {
  color: var(--accent);
  font-size: 2.4rem;
  line-height: 1;
}

.bitmap-opening aside span {
  font-size: 1.05rem;
}

.bitmap-opening aside small {
  color: var(--ink-soft);
  font-size: 0.82rem;
}

.bitmap-controls,
.founder-controls {
  padding: 0.8rem;
  border-bottom: 1px solid var(--line);
}

.bitmap-stage {
  min-height: 9rem;
  padding: 1rem;
  overflow-x: auto;
}

.bitmap-heading {
  display: flex;
  justify-content: space-between;
  gap: 1rem;
  margin-bottom: 0.7rem;
  font-family: var(--mono);
  font-size: 0.8rem;
}

.bitmap-cells {
  min-width: 640px;
  display: grid;
  grid-template-columns: repeat(var(--count), minmax(7px, 1fr));
  gap: 2px;
}

.bitmap-cell {
  height: 2.25rem;
  display: grid;
  place-items: center;
  border: 1px solid var(--line-soft);
  color: transparent;
  font-family: var(--mono);
  font-size: 0.72rem;
}

.bitmap-cell.survivor {
  background: var(--ink);
  border-color: var(--ink);
  color: var(--paper);
}

.bitmap-cell.removed {
  background:
    linear-gradient(45deg, transparent 44%, var(--accent) 45% 55%, transparent 56%),
    linear-gradient(-45deg, transparent 44%, var(--accent) 45% 55%, transparent 56%);
  border-color: var(--accent);
}

.bitmap-key {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: 0.8rem 1.4rem;
  padding: 0.65rem;
  border-top: 1px solid var(--line);
  font-family: var(--mono);
  font-size: 0.74rem;
}

.bitmap-key span {
  display: inline-flex;
  align-items: center;
  gap: 0.35rem;
}

.bitmap-key i {
  width: 0.85rem;
  height: 0.85rem;
  border: 1px solid var(--line);
}

.bitmap-key i.survivor {
  background: var(--ink);
}

.bitmap-key i.removed {
  background:
    linear-gradient(45deg, transparent 42%, var(--accent) 43% 57%, transparent 58%),
    linear-gradient(-45deg, transparent 42%, var(--accent) 43% 57%, transparent 58%);
}

.descent-example {
  padding: 1.3rem;
  border-block: 1px solid var(--line);
}

.descent-example > div:last-child strong {
  font-size: 1.2rem;
}

.founder-text > p {
  margin: 0;
}

.founder-display {
  display: grid;
  grid-template-columns: minmax(0, 1fr) 18rem;
}

.founder-bits {
  display: grid;
  grid-template-columns: repeat(7, 1fr);
  gap: 0.5rem;
  align-items: center;
  min-height: 12rem;
  padding: 1.5rem;
  border-right: 1px solid var(--line);
}

.founder-bit {
  min-height: 5rem;
  display: grid;
  place-items: center;
  border: 1px solid var(--line);
  color: var(--muted);
  font-family: var(--mono);
}

.founder-bit.active {
  background: var(--ink);
  border-color: var(--accent);
  color: var(--paper);
  box-shadow: inset 0 -4px 0 var(--accent);
}

.founder-readout {
  display: flex;
  flex-direction: column;
  justify-content: center;
  gap: 0.5rem;
  padding: 1.2rem;
}

.founder-readout span,
.founder-readout small {
  color: var(--ink-soft);
  font-size: 0.76rem;
}

.founder-readout strong {
  font-size: 1.15rem;
}

.founder-lineage {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: 0.6rem 1rem;
  padding: 0.8rem;
  border-top: 1px solid var(--line);
  font-family: var(--mono);
  font-size: 0.75rem;
}

.founder-lineage b {
  color: var(--accent);
}

.archive-grid {
  display: grid;
  grid-template-columns: minmax(0, 1fr) 11rem;
  min-height: 22rem;
}

.archive-grid svg {
  width: 100%;
  height: auto;
  border-right: 1px solid var(--line);
}

.archive-lines path {
  fill: none;
  stroke: var(--line);
  stroke-width: 2;
}

.archive-node rect {
  fill: var(--panel-solid);
  stroke: var(--line);
}

.archive-node text {
  fill: var(--ink);
  font-family: var(--mono);
  font-size: 17px;
  text-anchor: middle;
}

.archive-node.active rect {
  stroke: var(--accent);
}

.archive-node.muted {
  opacity: 0.38;
}

.archive-key {
  display: grid;
  grid-template-columns: 2.4rem 1fr;
  align-content: center;
  gap: 0.7rem;
  padding: 1rem;
  font-family: var(--mono);
  font-size: 0.75rem;
}

.archive-key strong {
  padding: 0.2rem;
  border: 1px solid var(--line);
  text-align: center;
}

.archive-key strong.accent {
  border-color: var(--accent);
  color: var(--accent);
}

.representation-tradeoff,
.three-findings {
  display: grid;
  border: 1px solid var(--line);
}

.representation-tradeoff {
  grid-template-columns: repeat(2, 1fr);
}

.representation-tradeoff > div,
.three-findings > div {
  padding: 1.2rem;
  border-right: 1px solid var(--line);
}

.representation-tradeoff > div:last-child,
.three-findings > div:last-child {
  border-right: 0;
}

.representation-tradeoff span,
.three-findings span {
  display: block;
  color: var(--accent);
  font-size: 0.74rem;
}

.representation-tradeoff p,
.three-findings p {
  margin: 0.5rem 0 0;
  color: var(--ink-soft);
}

.state-example {
  display: grid;
  grid-template-columns: auto auto;
  gap: 0.25rem 1rem;
  padding: 1.1rem;
  border: 1px solid var(--line);
}

.state-example i {
  grid-row: 1 / 3;
  grid-column: 3;
  align-self: center;
}

.state-example span {
  color: var(--ink-soft);
  font-size: 0.75rem;
}

.state-example strong {
  font-size: 1.4rem;
}

.transducer-section {
  margin: 4rem 0;
}

.transducer-section > .section-intro {
  max-width: 720px;
}

table {
  width: min(650px, 100%);
  margin: 1.5rem auto;
  border-collapse: collapse;
  font-family: var(--mono);
  font-size: 0.88rem;
}

caption {
  padding: 0.45rem;
  color: var(--ink-soft);
  font-size: 0.74rem;
}

th,
td {
  padding: 0.6rem;
  border: 1px solid var(--line);
  text-align: center;
}

th {
  background: var(--accent-soft);
}

.child-law {
  display: grid;
  gap: 0.5rem;
  max-width: 760px;
  margin: 1.5rem auto 0;
  padding: 1rem;
  border-block: 3px double var(--line);
  text-align: center;
}

.child-law span {
  color: var(--accent);
  font-family: var(--mono);
  font-size: 0.75rem;
}

.child-law strong {
  font-size: 1.25rem;
}

.worked-branch {
  display: grid;
  grid-template-columns: 0.8fr 1.3fr;
  gap: 2rem;
  margin: 4rem 0;
}

.worked-branch ol {
  margin: 0;
  padding: 0;
  border-top: 1px solid var(--line);
  list-style: none;
}

.worked-branch li {
  display: grid;
  grid-template-columns: 7rem minmax(0, 1fr);
  gap: 0.2rem 1rem;
  padding: 0.8rem;
  border-bottom: 1px solid var(--line);
}

.worked-branch li span,
.worked-branch li small {
  color: var(--ink-soft);
  font-family: var(--mono);
  font-size: 0.75rem;
}

.worked-branch li small {
  grid-column: 2;
}

.trie-toolbar {
  display: flex;
  justify-content: space-between;
  gap: 1rem;
  padding: 0.8rem;
  border-bottom: 1px solid var(--line);
}

.trit-key {
  display: flex;
  flex-wrap: wrap;
  gap: 0.7rem;
  align-items: center;
  font-family: var(--mono);
  font-size: 0.72rem;
}

.trit-key b {
  color: var(--accent);
}

.trie-body {
  display: grid;
  grid-template-columns: minmax(0, 1fr) 17rem;
}

.trie-scroll {
  overflow: auto;
  border-right: 1px solid var(--line);
}

.trie-canvas {
  position: relative;
  min-width: 620px;
  min-height: 450px;
}

.trie-node {
  width: 2.6rem;
  min-height: 2.6rem;
  display: grid;
  place-items: center;
  padding: 0.15rem;
  font-family: var(--mono);
}

.trie-node small {
  color: var(--ink-soft);
  font-size: 0.75rem;
  line-height: 1;
}

.trie-node.root {
  width: 3.8rem;
  border: 3px double var(--accent);
}

.trie-node.terminal {
  width: 2rem;
  min-height: 2rem;
  border-color: var(--accent);
  color: var(--accent);
}

.trie-node[aria-pressed="true"] {
  background: var(--ink);
  color: var(--paper);
}

.trie-body aside {
  padding: 1.2rem;
}

.trie-body aside span,
.trie-words span {
  color: var(--accent);
  font-family: var(--mono);
  font-size: 0.73rem;
}

.trie-body aside strong {
  display: block;
  margin: 0.4rem 0;
}

.trie-body aside p {
  color: var(--ink-soft);
  font-size: 0.92rem;
}

.trie-words {
  display: grid;
  gap: 0.35rem;
  padding: 0.8rem;
  border-top: 1px solid var(--line);
}

.trie-words strong {
  font-family: var(--mono);
  font-size: 0.75rem;
  line-height: 1.8;
  overflow-wrap: anywhere;
}

.machine-context {
  grid-template-columns: 0.8fr 1fr 0.7fr;
}

.machine-context aside {
  padding-left: 1rem;
  border-left: 3px solid var(--accent);
  color: var(--ink-soft);
  font-size: 0.9rem;
}

.machine-tabs {
  padding: 0.8rem;
  border-bottom: 1px solid var(--line);
}

.machine-layout {
  display: grid;
  grid-template-columns: minmax(0, 1.6fr) minmax(16rem, 0.7fr);
}

.machine-diagram {
  min-height: 34rem;
  display: grid;
  place-items: center;
  padding: 1rem;
  border-right: 1px solid var(--line);
  overflow-x: auto;
}

.machine-diagram svg {
  width: 100%;
  min-width: 650px;
  height: auto;
}

.machine-edge {
  fill: none;
  stroke: var(--line);
  stroke-width: 2;
}

.machine-label-bg {
  fill: var(--panel-solid);
  stroke: var(--line-soft);
}

.machine-label-text,
.machine-state text {
  fill: var(--ink);
  font-family: var(--mono);
  text-anchor: middle;
}

.machine-label-text {
  font-size: 16px;
}

.machine-state circle,
.machine-state rect {
  fill: var(--panel-solid);
  stroke: var(--ink);
  stroke-width: 2;
}

.machine-state.start circle:first-child,
.machine-state.return rect {
  stroke: var(--accent);
}

.machine-state text {
  font-size: 20px;
  font-weight: 700;
}

.machine-guide {
  align-content: start;
  display: grid;
  gap: 0.8rem;
  padding: 1rem;
}

.machine-guide > p {
  margin: 0;
  color: var(--ink-soft);
  font-family: var(--mono);
  font-size: 0.75rem;
}

.machine-state-card {
  border-top: 1px solid var(--line);
}

.machine-state-card h4 {
  display: flex;
  justify-content: space-between;
  margin: 0;
  padding: 0.45rem 0;
  color: var(--accent);
  font-family: var(--mono);
  font-size: 0.82rem;
}

.machine-state-card p {
  display: grid;
  grid-template-columns: 4.8rem 1fr;
  gap: 0.5rem;
  margin: 0;
  padding: 0.25rem 0;
  font-family: var(--mono);
  font-size: 0.72rem;
}

.machine-state-card p b {
  text-align: right;
}

.lut-intro {
  align-items: center;
}

.packing-stat {
  padding: 1.1rem;
  border: 1px solid var(--line);
  text-align: center;
}

.packing-stat strong,
.packing-stat span {
  display: block;
}

.packing-stat strong {
  color: var(--accent);
  font-size: 1.7rem;
}

.packing-stat span {
  font-size: 0.78rem;
}

.lut-grid {
  display: grid;
  grid-template-columns: 1.4fr 0.8fr 0.8fr;
}

.lut-grid > div {
  min-height: 10rem;
  display: flex;
  flex-direction: column;
  justify-content: center;
  gap: 0.55rem;
  padding: 1rem;
  border-right: 1px solid var(--line);
}

.lut-grid > div:last-child {
  border-right: 0;
}

.lut-grid span,
.lut-grid small {
  color: var(--ink-soft);
  font-family: var(--mono);
  font-size: 0.73rem;
}

.lut-grid strong {
  font-size: 1.08rem;
}

.three-findings {
  grid-template-columns: repeat(3, 1fr);
}

.comparison-table {
  border: 1px solid var(--line);
}

.table-row {
  display: grid;
  grid-template-columns: 0.8fr 1.25fr 1fr 1.2fr;
  border-bottom: 1px solid var(--line);
}

.table-row:last-child {
  border-bottom: 0;
}

.table-row > * {
  padding: 0.75rem;
  border-right: 1px solid var(--line);
}

.table-row > *:last-child {
  border-right: 0;
}

.table-head {
  background: var(--accent-soft);
  font-family: var(--mono);
  font-size: 0.75rem;
}

.references {
  padding-bottom: 3.8rem;
}

.reference-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  border: 1px solid var(--line);
}

.reference-grid > a,
.reference-grid > div {
  min-height: 7rem;
  display: flex;
  flex-direction: column;
  justify-content: center;
  gap: 0.4rem;
  padding: 1rem;
  border-right: 1px solid var(--line);
  border-bottom: 1px solid var(--line);
  text-decoration: none;
}

.reference-grid > :nth-child(3) {
  border-right: 0;
}

.reference-grid > :nth-last-child(-n + 2) {
  border-bottom: 0;
}

.reference-grid > :last-child {
  grid-column: span 2;
  border-right: 0;
}

.reference-grid p {
  margin: 0;
}

.reference-grid small {
  color: var(--ink-soft);
  font-size: 0.75rem;
}

.archive-link {
  margin-left: 0.45rem;
  color: var(--ink-soft);
  font-family: var(--mono);
  font-size: 0.75rem;
  font-weight: 400;
}

footer {
  display: flex;
  justify-content: space-between;
  gap: 1rem;
  padding: 1.2rem 0;
  border-top: 3px double var(--line);
  color: var(--ink-soft);
  font-size: 0.75rem;
}

@media (max-width: 900px) {
  html {
    scroll-padding-top: 10rem;
  }

  .section-nav {
    grid-template-columns: repeat(3, 1fr);
  }

  .chapter-header {
    grid-template-columns: 7rem 1fr;
  }

  .chapter-header > p {
    grid-column: 2;
  }

  .project-index,
  .pair-grid,
  .three-findings {
    grid-template-columns: 1fr;
  }

  .project-index a,
  .pair-grid > div,
  .three-findings > div {
    min-height: auto;
    border-right: 0;
    border-bottom: 1px solid var(--line);
  }

  .project-index a:last-child,
  .pair-grid > div:last-child,
  .three-findings > div:last-child {
    border-bottom: 0;
  }

  .prior-rules,
  .worked-branch,
  .machine-context {
    grid-template-columns: 1fr;
  }

  .machine-context aside {
    padding: 0.9rem 0 0;
    border-left: 0;
    border-top: 3px solid var(--accent);
  }

  .certificate {
    grid-template-columns: auto auto auto auto;
  }

  .certificate p {
    grid-column: 1 / -1;
    padding: 0.8rem 0 0;
    border-top: 1px solid var(--line);
    border-left: 0;
  }

  .storage-section,
  .bitmap-opening,
  .ternary-intro {
    grid-template-columns: 1fr;
  }

  .machine-layout {
    grid-template-columns: 1fr;
  }

  .machine-diagram {
    border-right: 0;
    border-bottom: 1px solid var(--line);
  }

  .machine-guide {
    grid-template-columns: repeat(2, 1fr);
  }

  .machine-guide > p {
    grid-column: 1 / -1;
  }

  .lut-grid {
    grid-template-columns: 1fr 1fr;
  }

  .lut-grid > div:first-child {
    grid-column: 1 / -1;
    border-right: 0;
    border-bottom: 1px solid var(--line);
  }

  .table-row {
    grid-template-columns: 0.8fr 1.2fr 1fr;
  }

  .table-row > :last-child {
    display: none;
  }
}

@media (max-width: 680px) {
  body {
    font-size: 17px;
  }

  .site-header {
    align-items: flex-start;
    flex-direction: column;
    padding: 0.8rem 0;
  }

  .site-identity {
    align-items: flex-start;
    flex-direction: column;
    gap: 0;
  }

  .theme-control {
    width: 100%;
  }

  .theme-control button {
    flex: 1;
  }

  .section-nav {
    width: 100%;
  }

  .section-nav a {
    font-size: 0.75rem;
  }

  .section-nav a span {
    display: block;
    margin: 0;
  }

  main {
    width: 100%;
    border-inline: 0;
  }

  .hero,
  .chapter {
    padding: 3.4rem 1rem;
  }

  .hero {
    padding-top: 3.8rem;
  }

  h1 {
    font-size: 2.25rem;
  }

  h2 {
    font-size: 1.9rem;
  }

  .chapter-header {
    grid-template-columns: 1fr;
    gap: 0.7rem;
  }

  .chapter-header > div {
    flex-direction: row;
    align-items: baseline;
    gap: 0.7rem;
  }

  .chapter-header > p {
    grid-column: auto;
  }

  .two-column,
  .two-culls,
  .conclusions,
  .representation-tradeoff {
    grid-template-columns: 1fr;
  }

  .note-block + .note-block {
    border-top: 0;
    border-left: 1px solid var(--line);
  }

  .two-culls > div,
  .conclusions > div,
  .representation-tradeoff > div {
    border-right: 0;
    border-bottom: 1px solid var(--line);
  }

  .two-culls > div:last-child,
  .conclusions > div:last-child,
  .representation-tradeoff > div:last-child {
    border-bottom: 0;
  }

  .reverse-definition,
  .length-cull,
  .founder-text,
  .descent-example,
  .lut-intro {
    grid-template-columns: 1fr;
  }

  .formula-strip {
    grid-template-columns: 1fr;
  }

  .formula-strip > span {
    border-right: 0;
    border-bottom: 1px solid var(--line);
  }

  .formula-strip > span:last-child {
    border-bottom: 0;
  }

  .walk-toolbar,
  .walk-readout {
    grid-template-columns: 1fr;
  }

  .walk-toolbar > div,
  .walk-toolbar label,
  .walk-readout > div {
    border-right: 0;
    border-bottom: 1px solid var(--line);
  }

  .walk-toolbar > *:last-child,
  .walk-readout > div:last-child {
    border-bottom: 0;
  }

  .certificate {
    grid-template-columns: 1fr auto 2rem auto;
  }

  .certificate > span {
    grid-column: 1 / -1;
  }

  .storage-bars > div {
    grid-template-columns: 1fr 5rem;
  }

  .storage-bars i {
    grid-column: 1 / -1;
    grid-row: 2;
  }

  .storage-bars b {
    grid-column: 2;
    grid-row: 1;
  }

  .founder-display,
  .trie-body,
  .archive-grid {
    grid-template-columns: 1fr;
  }

  .founder-bits,
  .trie-scroll,
  .archive-grid svg {
    border-right: 0;
    border-bottom: 1px solid var(--line);
  }

  .founder-bits {
    gap: 0.25rem;
    padding: 0.7rem;
  }

  .founder-bit {
    min-height: 3.5rem;
    font-size: 0.72rem;
  }

  .archive-key {
    grid-template-columns: 2.4rem 1fr 2.4rem 1fr;
  }

  .trie-toolbar {
    align-items: flex-start;
    flex-direction: column;
  }

  .machine-guide {
    grid-template-columns: 1fr;
  }

  .lut-grid {
    grid-template-columns: 1fr;
  }

  .lut-grid > div,
  .lut-grid > div:first-child {
    grid-column: auto;
    border-right: 0;
    border-bottom: 1px solid var(--line);
  }

  .lut-grid > div:last-child {
    border-bottom: 0;
  }

  .table-row,
  .table-row.table-head {
    grid-template-columns: 1fr 1.5fr;
  }

  .table-row > :nth-child(n + 3) {
    display: none;
  }

  .reference-grid {
    grid-template-columns: 1fr;
  }

  .reference-grid > a,
  .reference-grid > div,
  .reference-grid > :nth-child(3),
  .reference-grid > :last-child {
    grid-column: auto;
    min-height: 5.5rem;
    border-right: 0;
    border-bottom: 1px solid var(--line);
  }

  .reference-grid > :last-child {
    border-bottom: 0;
  }

  footer {
    width: calc(100% - 2rem);
    align-items: flex-start;
    flex-direction: column;
  }
}

@media (prefers-reduced-motion: reduce) {
  html {
    scroll-behavior: auto;
  }
}