:root {
  color-scheme: light;
  --paper: #f2eee5;
  --paper-deep: #e7dfd1;
  --ink: #171815;
  --ink-soft: #505149;
  --line: #c8bfae;
  --line-strong: #968b7c;
  --signal: #c44732;
  --signal-dark: #8e2e20;
  --blue: #214e68;
  --blue-pale: #dce6e8;
  --white: #fffefa;
  --display: "Iowan Old Style", "Baskerville", "Palatino Linotype", Palatino, Georgia, serif;
  --sans: "Avenir Next", Avenir, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  --mono: "SFMono-Regular", "Cascadia Code", "Roboto Mono", Consolas, monospace;
  --max: 1220px;
  --gutter: clamp(1.25rem, 4vw, 4rem);
}

* {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  color: var(--ink);
  background:
    radial-gradient(circle at 14% 8%, rgb(255 255 255 / 48%) 0 10rem, transparent 28rem),
    linear-gradient(90deg, transparent 0 calc(100% - 1px), rgb(23 24 21 / 3%) 100%),
    var(--paper);
  font-family: var(--sans);
  font-size: 1rem;
  line-height: 1.65;
  text-rendering: optimizeLegibility;
  -webkit-font-smoothing: antialiased;
}

body::before {
  position: fixed;
  inset: 0;
  z-index: -1;
  pointer-events: none;
  content: "";
  opacity: 0.22;
  background-image: url("data:image/svg+xml,%3Csvg viewBox='0 0 180 180' xmlns='http://www.w3.org/2000/svg'%3E%3Cfilter id='n'%3E%3CfeTurbulence type='fractalNoise' baseFrequency='.92' numOctaves='3' stitchTiles='stitch'/%3E%3C/filter%3E%3Crect width='100%25' height='100%25' filter='url(%23n)' opacity='.12'/%3E%3C/svg%3E");
}

::selection {
  color: var(--white);
  background: var(--signal);
}

a {
  color: inherit;
  text-decoration-color: rgb(23 24 21 / 40%);
  text-underline-offset: 0.2em;
}

a:hover {
  text-decoration-color: currentColor;
}

img {
  display: block;
  max-width: 100%;
  height: auto;
}

button,
a {
  -webkit-tap-highlight-color: transparent;
}

button:focus-visible,
a:focus-visible,
[tabindex]:focus-visible {
  outline: 3px solid var(--signal);
  outline-offset: 4px;
}

.skip-link {
  position: fixed;
  top: 0.75rem;
  left: 0.75rem;
  z-index: 100;
  padding: 0.65rem 0.9rem;
  color: var(--white);
  background: var(--ink);
  transform: translateY(-150%);
}

.skip-link:focus {
  transform: translateY(0);
}

/* Header */
.site-header {
  position: relative;
  z-index: 10;
  display: grid;
  grid-template-columns: 1fr auto 1fr;
  align-items: center;
  width: min(calc(100% - (2 * var(--gutter))), var(--max));
  min-height: 5.4rem;
  margin: 0 auto;
  border-bottom: 1px solid var(--ink);
}

.wordmark {
  display: inline-flex;
  gap: 0.7rem;
  align-items: center;
  width: max-content;
  font-weight: 700;
  font-size: 1.05rem;
  letter-spacing: -0.02em;
  text-decoration: none;
}

.wordmark img {
  width: 2.35rem;
  height: 2.35rem;
  object-fit: contain;
}

.site-header nav {
  display: flex;
  gap: clamp(1rem, 2.4vw, 2.1rem);
  font-size: 0.78rem;
  font-weight: 650;
  letter-spacing: 0.08em;
  text-transform: uppercase;
}

.site-header nav a,
.header-links a {
  text-decoration: none;
}

.site-header nav a {
  position: relative;
}

.site-header nav a::after {
  position: absolute;
  right: 0;
  bottom: -0.35rem;
  left: 0;
  height: 1px;
  content: "";
  background: currentColor;
  transform: scaleX(0);
  transform-origin: right;
  transition: transform 180ms ease;
}

.site-header nav a:hover::after {
  transform: scaleX(1);
  transform-origin: left;
}

.header-links {
  justify-self: end;
  display: flex;
  gap: 1.15rem;
  font-size: 0.82rem;
  font-weight: 650;
}

.header-links a:hover {
  color: var(--signal-dark);
}

/* Layout Containers */
.hero,
.method,
.evidence,
.scaling,
.citation,
footer {
  width: min(calc(100% - (2 * var(--gutter))), var(--max));
  margin-inline: auto;
}

/* Hero */
.hero {
  padding: clamp(2.8rem, 6vw, 5.8rem) 0 clamp(3.8rem, 7vw, 6.8rem);
}

.hero-kicker {
  display: flex;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 0.75rem;
  margin-bottom: clamp(2rem, 4.5vw, 3.8rem);
  color: var(--ink-soft);
  font-size: 0.72rem;
  font-weight: 650;
  letter-spacing: 0.12em;
  text-transform: uppercase;
}

.hero-grid {
  display: grid;
  grid-template-columns: minmax(0, 1.32fr) minmax(18rem, 23.5rem);
  gap: clamp(2.5rem, 6vw, 5.5rem);
  align-items: end;
}

.eyebrow {
  margin: 0 0 0.9rem;
  color: var(--signal-dark);
  font-size: 0.72rem;
  font-weight: 700;
  letter-spacing: 0.15em;
  text-transform: uppercase;
}

h1,
h2,
h3,
p {
  margin-top: 0;
}

h1,
h2,
h3 {
  font-family: var(--display);
  font-weight: 600;
}

.title-row {
  display: flex;
  align-items: center;
  gap: 1.15rem;
  margin-bottom: 0.45rem;
}

.hero-mascot {
  width: clamp(3.6rem, 6.5vw, 5.4rem);
  height: auto;
  flex-shrink: 0;
}

h1 {
  margin-bottom: 1.5rem;
  font-size: clamp(3.4rem, 7.4vw, 6.6rem);
  letter-spacing: -0.055em;
  line-height: 0.9;
}

h1 > span {
  display: block;
  max-width: 26ch;
  margin-top: 0.38em;
  color: var(--ink-soft);
  font-family: var(--sans);
  font-size: clamp(1.18rem, 2.15vw, 1.82rem);
  font-weight: 600;
  letter-spacing: -0.025em;
  line-height: 1.22;
}

.deck {
  max-width: 45rem;
  margin-bottom: 1.85rem;
  font-family: var(--display);
  font-size: clamp(1.12rem, 1.8vw, 1.42rem);
  line-height: 1.5;
}

.hero-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 0.65rem;
  margin-bottom: 1.7rem;
}

.button {
  display: inline-flex;
  min-height: 2.9rem;
  align-items: center;
  justify-content: center;
  padding: 0.65rem 1.05rem;
  border: 1px solid var(--ink);
  font-size: 0.78rem;
  font-weight: 700;
  letter-spacing: 0.06em;
  text-decoration: none;
  text-transform: uppercase;
  transition:
    color 160ms ease,
    background 160ms ease,
    transform 160ms ease;
}

.button:hover {
  transform: translateY(-2px);
}

.button-primary {
  color: var(--white);
  background: var(--ink);
}

.button-primary:hover {
  background: var(--signal-dark);
  border-color: var(--signal-dark);
}

.button-accent {
  color: var(--white);
  background: var(--signal-dark);
  border-color: var(--signal-dark);
}

.button-accent:hover {
  background: var(--ink);
  border-color: var(--ink);
}

.button-secondary:hover {
  color: var(--paper);
  background: var(--blue);
  border-color: var(--blue);
}

.authors-block {
  border-top: 1px solid var(--line);
  padding-top: 1rem;
}

.authors {
  display: flex;
  flex-wrap: wrap;
  gap: 0.35rem 0.75rem;
  margin-bottom: 0.35rem;
  color: var(--ink);
  font-size: 0.96rem;
  font-weight: 600;
}

.authors sup,
.affiliations sup {
  color: var(--signal-dark);
  font-weight: 700;
}

.affiliations {
  display: flex;
  flex-wrap: wrap;
  gap: 0.25rem 1.1rem;
  margin: 0;
  color: var(--ink-soft);
  font-size: 0.83rem;
}

/* Hero Ledger */
.hero-ledger {
  border-top: 5px solid var(--signal);
  border-bottom: 1px solid var(--ink);
}

.ledger-label {
  margin: 0;
  padding: 0.75rem 0;
  border-bottom: 1px solid var(--line);
  color: var(--ink-soft);
  font-size: 0.7rem;
  font-weight: 700;
  letter-spacing: 0.14em;
  text-transform: uppercase;
}

.hero-ledger dl {
  margin: 0;
}

.hero-ledger dl > div {
  display: grid;
  grid-template-columns: 6.1rem 1fr;
  gap: 0.95rem;
  align-items: center;
  padding: 0.95rem 0;
  border-bottom: 1px solid var(--line);
}

.hero-ledger dt {
  font-family: var(--display);
  font-size: 2.15rem;
  font-weight: 600;
  letter-spacing: -0.05em;
  color: var(--ink);
}

.hero-ledger dl > div:first-child dt {
  color: var(--signal-dark);
}

.hero-ledger dd {
  margin: 0;
  color: var(--ink-soft);
  font-size: 0.83rem;
  line-height: 1.45;
}

.ledger-note {
  margin: 0;
  padding: 0.9rem 0;
  color: var(--signal-dark);
  font-family: var(--display);
  font-size: 0.92rem;
  line-height: 1.45;
}

/* Problem / Abstract Dark Band */
.section-grid {
  display: grid;
  grid-template-columns: minmax(3.5rem, 0.18fr) minmax(0, 1.1fr) minmax(18rem, 0.95fr);
  gap: clamp(1.5rem, 4vw, 3.8rem);
  width: min(100%, 1500px);
  margin-inline: auto;
  padding: clamp(3.8rem, 7vw, 6.8rem) var(--gutter);
  color: var(--white);
  background: var(--ink);
}

.section-index {
  color: #928f84;
  font-family: var(--display);
  font-size: clamp(2rem, 3.8vw, 4rem);
}

.question .eyebrow {
  color: #e87b65;
}

.question h2 {
  max-width: 22ch;
  margin: 0;
  font-size: clamp(2rem, 4vw, 3.7rem);
  letter-spacing: -0.04em;
  line-height: 1.06;
}

.question-answer {
  align-self: end;
  margin: 0;
  color: #dcd8ce;
  font-family: var(--display);
  font-size: clamp(1rem, 1.35vw, 1.16rem);
  line-height: 1.58;
}

/* Signal Callout Band */
.definition {
  display: grid;
  grid-template-columns: minmax(9rem, 0.32fr) minmax(0, 1fr) minmax(15rem, 0.48fr);
  gap: clamp(1.8rem, 4.5vw, 4.5rem);
  width: min(100%, 1500px);
  margin: 0 auto;
  padding: clamp(3rem, 5.5vw, 5rem) var(--gutter);
  background: var(--signal);
}

.definition-label {
  padding-top: 0.45rem;
  color: #4a140c;
  font-size: 0.72rem;
  font-weight: 750;
  letter-spacing: 0.14em;
  text-transform: uppercase;
}

.definition h2 {
  margin-bottom: 0.85rem;
  font-size: clamp(2.1rem, 4.2vw, 3.9rem);
  letter-spacing: -0.045em;
  line-height: 1.02;
  color: #171815;
}

.definition-copy p,
.definition-stat span {
  max-width: 46rem;
  margin: 0;
  color: #350f09;
}

.definition-copy p {
  font-family: var(--display);
  font-size: clamp(1.04rem, 1.45vw, 1.24rem);
  line-height: 1.52;
}

.definition-stat {
  display: flex;
  flex-direction: column;
  justify-content: flex-end;
  border-left: 1px solid rgb(53 15 9 / 36%);
  padding-left: clamp(1.4rem, 3vw, 2.6rem);
}

.definition-stat strong {
  display: block;
  font-family: var(--display);
  font-size: clamp(2.8rem, 5.5vw, 5.2rem);
  font-weight: 600;
  letter-spacing: -0.06em;
  line-height: 0.96;
  color: #171815;
}

.definition-stat span {
  margin-top: 0.85rem;
  font-size: 0.83rem;
  line-height: 1.48;
}

/* Main Sections */
.method,
.evidence,
.scaling,
.citation {
  padding: clamp(4.2rem, 8vw, 7.5rem) 0;
}

.evidence,
.scaling,
.citation {
  border-top: 1px solid var(--line-strong);
}

.section-heading {
  display: grid;
  grid-template-columns: minmax(0, 1.2fr) minmax(16rem, 0.6fr);
  gap: clamp(2rem, 6vw, 6rem);
  align-items: end;
  margin-bottom: clamp(2.6rem, 5vw, 4.2rem);
  padding-bottom: 1.35rem;
  border-bottom: 1px solid var(--ink);
}

.section-heading h2,
.citation h2 {
  max-width: 20ch;
  margin: 0;
  font-size: clamp(2.3rem, 4.8vw, 4.4rem);
  letter-spacing: -0.048em;
  line-height: 1.01;
}

.section-heading > p {
  margin: 0;
  color: var(--ink-soft);
  font-size: 0.93rem;
  line-height: 1.58;
}

/* Paper Figures */
.paper-figure {
  margin: 0;
  padding: clamp(0.9rem, 2vw, 1.5rem);
  background: var(--white);
  border: 1px solid var(--line);
  box-shadow: 0 18px 60px rgb(49 39 25 / 9%);
}

.paper-figure img {
  width: 100%;
}

.paper-figure figcaption {
  display: grid;
  grid-template-columns: auto 1fr;
  gap: 1.1rem;
  margin-top: 1rem;
  padding-top: 0.85rem;
  border-top: 1px solid var(--line);
  color: var(--ink-soft);
  font-family: var(--display);
  font-size: 0.92rem;
  line-height: 1.52;
}

.paper-figure figcaption span {
  color: var(--signal-dark);
  font-family: var(--sans);
  font-size: 0.68rem;
  font-weight: 750;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  padding-top: 0.18rem;
}

.wide-figure {
  margin-bottom: clamp(2.8rem, 5.5vw, 4.5rem);
}

/* Method Pillars & Primitives */
.method-steps {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 0;
  margin: 0 0 clamp(2.8rem, 5vw, 4.2rem);
  padding: 0;
  list-style: none;
  border-top: 1px solid var(--ink);
  border-bottom: 1px solid var(--ink);
}

.method-steps li {
  position: relative;
  padding: 1.6rem clamp(1.2rem, 2.6vw, 2.2rem) 2.2rem;
  border-right: 1px solid var(--line);
}

.method-steps li:first-child {
  padding-left: 0;
}

.method-steps li:last-child {
  padding-right: 0;
  border-right: 0;
}

.step-number {
  display: block;
  margin-bottom: 2rem;
  color: var(--signal);
  font-family: var(--display);
  font-size: 1.05rem;
  font-weight: 700;
}

.method-steps h3 {
  margin-bottom: 0.65rem;
  font-size: 1.65rem;
  letter-spacing: -0.03em;
  line-height: 1.15;
}

.method-steps p {
  margin: 0;
  color: var(--ink-soft);
  font-size: 0.9rem;
  line-height: 1.6;
}

/* Tables */
.table-wrap {
  overflow-x: auto;
  margin-bottom: clamp(2.8rem, 5.5vw, 4.5rem);
  border-top: 2px solid var(--ink);
  border-bottom: 2px solid var(--ink);
}

.table-wrap:last-child {
  margin-bottom: 0;
}

table {
  width: 100%;
  min-width: 780px;
  border-collapse: collapse;
  font-size: 0.85rem;
}

caption {
  padding: 0.95rem 0;
  color: var(--ink-soft);
  font-family: var(--display);
  font-size: 1rem;
  text-align: left;
}

th,
td {
  padding: 0.95rem 0.8rem;
  border-top: 1px solid var(--line);
  text-align: left;
  vertical-align: top;
}

thead th {
  color: var(--ink-soft);
  font-size: 0.68rem;
  letter-spacing: 0.08em;
  text-transform: uppercase;
}

tbody th {
  font-family: var(--display);
  font-size: 0.96rem;
  font-weight: 600;
}

tr.highlight-row {
  background: rgb(196 71 50 / 8%);
}

tr.highlight-row th,
tr.highlight-row td {
  color: var(--ink);
  font-weight: 600;
}

tr.highlight-row td strong {
  color: var(--signal-dark);
}

code {
  font-family: var(--mono);
  font-size: 0.83em;
}

p code,
td code,
th code,
li code {
  padding: 0.12em 0.36em;
  background: rgb(23 24 21 / 6%);
  border-radius: 3px;
}

/* Phase Transition Box */
.composition {
  display: grid;
  grid-template-columns: minmax(0, 1.05fr) minmax(18rem, 0.75fr);
  gap: clamp(2.2rem, 5.5vw, 5.5rem);
  margin-top: clamp(2.8rem, 5vw, 4.2rem);
  padding: clamp(2rem, 4.5vw, 3.8rem);
  color: var(--white);
  background: var(--ink);
}

.composition h3 {
  max-width: 20ch;
  margin-bottom: 1.1rem;
  font-size: clamp(1.9rem, 3.5vw, 3.1rem);
  letter-spacing: -0.04em;
  line-height: 1.06;
}

.composition-copy > p:not(.eyebrow) {
  max-width: 42rem;
  color: #d8d4ca;
  font-size: 0.94rem;
}

.composition .eyebrow {
  color: #e87b65;
}

.composition .boundary {
  padding-top: 1rem;
  margin-bottom: 0;
  border-top: 1px solid #55564f;
  font-family: var(--display);
  font-size: 1.05rem;
  color: var(--white);
}

.composition-ledger {
  margin: 0;
  border-top: 1px solid #72736a;
}

.composition-ledger div {
  display: grid;
  grid-template-columns: 1fr auto;
  gap: 1rem;
  padding: 0.9rem 0;
  border-bottom: 1px solid #55564f;
}

.composition-ledger dt {
  color: #bebbb2;
  font-size: 0.8rem;
}

.composition-ledger dd {
  margin: 0;
  font-family: var(--display);
  font-size: 1.02rem;
}

.composition-ledger strong {
  color: #f1846d;
}

/* Citation */
.citation {
  display: grid;
  grid-template-columns: minmax(18rem, 0.55fr) minmax(0, 1.25fr);
  gap: clamp(2.5rem, 6vw, 6rem);
}

.citation-copy > p:not(.eyebrow) {
  max-width: 28rem;
  margin-top: 1.25rem;
  color: var(--ink-soft);
  font-size: 0.93rem;
}

.citation-links {
  display: flex;
  flex-wrap: wrap;
  gap: 0.65rem 1.15rem;
  margin-top: 1.7rem;
  font-size: 0.76rem;
  font-weight: 700;
  letter-spacing: 0.06em;
  text-transform: uppercase;
}

.code-card {
  align-self: end;
  overflow: hidden;
  color: #f0ece2;
  background: var(--ink);
}

.code-toolbar {
  display: grid;
  grid-template-columns: 1fr auto minmax(0, auto);
  gap: 0.8rem;
  align-items: center;
  min-height: 3.1rem;
  padding: 0.55rem 1rem;
  border-bottom: 1px solid #44453f;
  color: #b7b4aa;
  font-size: 0.68rem;
  letter-spacing: 0.08em;
  text-transform: uppercase;
}

.code-toolbar button {
  padding: 0.42rem 0.75rem;
  color: var(--ink);
  background: #e7dfd1;
  border: 0;
  cursor: pointer;
  font: inherit;
  font-weight: 750;
  letter-spacing: inherit;
  text-transform: inherit;
}

.code-toolbar button:hover {
  background: #f1846d;
}

.copy-status {
  min-width: 4.5rem;
  color: #f1846d;
  text-align: right;
}

pre {
  margin: 0;
  overflow-x: auto;
  padding: clamp(1.2rem, 2.6vw, 2.1rem);
}

pre code {
  padding: 0;
  background: transparent;
  font-size: 0.78rem;
  line-height: 1.72;
}

/* Footer */
footer {
  display: flex;
  justify-content: space-between;
  gap: 2rem;
  align-items: center;
  padding: 2rem 0 3rem;
  border-top: 1px solid var(--ink);
}

footer > div:first-child {
  display: flex;
  gap: 0.9rem;
  align-items: center;
}

footer > div:first-child img {
  width: 2.1rem;
  height: 2.1rem;
}

footer p {
  max-width: 34rem;
  margin: 0;
  color: var(--ink-soft);
  font-size: 0.78rem;
}

.footer-links {
  display: flex;
  flex-wrap: wrap;
  gap: 0.6rem 1.25rem;
  justify-content: flex-end;
  font-size: 0.75rem;
  font-weight: 650;
}

/* Responsive */
@media (max-width: 920px) {
  .site-header {
    grid-template-columns: 1fr auto;
  }

  .site-header nav {
    display: none;
  }

  .hero-grid,
  .section-heading,
  .composition,
  .citation {
    grid-template-columns: 1fr;
  }

  .hero-ledger {
    max-width: 38rem;
  }

  .section-grid {
    grid-template-columns: 3.5rem 1fr;
  }

  .question-answer {
    grid-column: 2;
  }

  .definition {
    grid-template-columns: 0.35fr 1fr;
  }

  .definition-stat {
    grid-column: 2;
    border-top: 1px solid rgb(53 15 9 / 36%);
    border-left: 0;
    padding-top: 1.25rem;
    padding-left: 0;
  }
}

@media (max-width: 680px) {
  body {
    font-size: 0.95rem;
  }

  .section-grid,
  .definition,
  .method-steps {
    grid-template-columns: 1fr;
  }

  .question-answer,
  .definition-stat {
    grid-column: 1;
  }

  .method-steps li,
  .method-steps li:first-child,
  .method-steps li:last-child {
    padding: 1.4rem 0 1.8rem;
    border-right: 0;
    border-bottom: 1px solid var(--line);
  }

  .method-steps li:last-child {
    border-bottom: 0;
  }

  .paper-figure figcaption {
    grid-template-columns: 1fr;
    gap: 0.35rem;
  }

  footer {
    align-items: flex-start;
    flex-direction: column;
  }

  .footer-links {
    justify-content: flex-start;
  }
}

@media (prefers-reduced-motion: no-preference) {
  .hero-copy > *,
  .hero-ledger {
    animation: reveal 650ms both;
  }

  .hero-copy > :nth-child(2) { animation-delay: 60ms; }
  .hero-copy > :nth-child(3) { animation-delay: 120ms; }
  .hero-copy > :nth-child(4) { animation-delay: 180ms; }
  .hero-copy > :nth-child(5),
  .hero-ledger { animation-delay: 240ms; }

  @keyframes reveal {
    from {
      opacity: 0;
      transform: translateY(14px);
    }
    to {
      opacity: 1;
      transform: translateY(0);
    }
  }
}