:root {
  color-scheme: light;
  --ink: #14233b;
  --ink-deep: #0b172b;
  --paper: #f5f2e9;
  --paper-bright: #fffdf7;
  --line: #cbd2d8;
  --line-dark: #46566d;
  --muted: #5d6878;
  --muted-light: #aab6c7;
  --accent: #0d6f78;
  --accent-light: #7fd1ca;
  --warning: #835425;
  --measure: 74rem;
  --reading: 47rem;
  --sans: Inter, ui-sans-serif, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  --serif: Charter, "Iowan Old Style", "Palatino Linotype", Palatino, Georgia, serif;
  --mono: "SFMono-Regular", Consolas, "Liberation Mono", monospace;
}

*,
*::before,
*::after {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  background: var(--paper);
  color: var(--ink);
  font-family: var(--sans);
  font-size: 1rem;
  line-height: 1.62;
  text-rendering: optimizeLegibility;
}

a {
  color: inherit;
  text-decoration-color: var(--accent);
  text-decoration-thickness: 0.1em;
  text-underline-offset: 0.18em;
}

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

a:focus-visible,
button:focus-visible {
  outline: 3px solid var(--accent-light);
  outline-offset: 4px;
}

img,
svg {
  display: block;
  max-width: 100%;
}

code {
  font-family: var(--mono);
  font-size: 0.89em;
  overflow-wrap: anywhere;
}

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

h1,
h2,
h3 {
  font-family: var(--serif);
  font-weight: 600;
  line-height: 1.08;
  text-wrap: balance;
}

h1 {
  font-size: clamp(2.85rem, 7vw, 6.4rem);
  letter-spacing: -0.045em;
}

h2 {
  font-size: clamp(2rem, 4vw, 3.75rem);
  letter-spacing: -0.03em;
}

h3 {
  font-size: clamp(1.35rem, 2vw, 1.85rem);
  letter-spacing: -0.018em;
}

.skip-link {
  position: fixed;
  top: 0.75rem;
  left: 0.75rem;
  z-index: 20;
  padding: 0.65rem 0.85rem;
  background: var(--paper-bright);
  color: var(--ink-deep);
  transform: translateY(-160%);
}

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

.site-header {
  position: sticky;
  top: 0;
  z-index: 10;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1.5rem;
  min-height: 4.5rem;
  padding: 0.8rem max(1.25rem, calc((100vw - var(--measure)) / 2));
  border-bottom: 1px solid var(--line);
  background: color-mix(in srgb, var(--paper-bright) 94%, transparent);
  backdrop-filter: blur(12px);
}

.wordmark {
  color: var(--ink-deep);
  font-family: var(--serif);
  font-size: 1.45rem;
  font-weight: 700;
  letter-spacing: -0.03em;
  text-decoration: none;
}

.site-header nav {
  display: flex;
  flex-wrap: wrap;
  justify-content: flex-end;
  gap: 0.45rem 1.3rem;
}

.site-header nav a {
  color: var(--ink);
  font-size: 0.83rem;
  font-weight: 650;
  letter-spacing: 0.04em;
  text-decoration: none;
  text-transform: uppercase;
}

.site-header nav a:hover {
  color: var(--accent);
}

.hero {
  display: grid;
  grid-template-columns: minmax(0, 0.95fr) minmax(24rem, 1.05fr);
  gap: clamp(2rem, 6vw, 6rem);
  align-items: center;
  min-height: calc(100vh - 4.5rem);
  padding-block: clamp(3.25rem, 6vh, 4.75rem);
  padding-inline: max(1.25rem, calc((100vw - var(--measure)) / 2));
  background: var(--ink-deep);
  color: var(--paper-bright);
}

.hero-copy {
  max-width: 48rem;
  animation: enter 700ms ease-out both;
}

.eyebrow,
.status {
  margin-bottom: 1rem;
  color: var(--accent);
  font-size: 0.76rem;
  font-weight: 750;
  letter-spacing: 0.13em;
  text-transform: uppercase;
}

.hero .eyebrow,
.hero .status,
.closing .eyebrow {
  color: var(--accent-light);
}

.hero h1 {
  max-width: 17ch;
  margin-bottom: 1.6rem;
  font-size: clamp(2.85rem, 5.1vw, 4.9rem);
  line-height: 1.03;
}

.lede {
  max-width: 45rem;
  color: #d8dfeb;
  font-size: clamp(1.08rem, 1.8vw, 1.28rem);
  line-height: 1.55;
}

.actions {
  display: flex;
  flex-wrap: wrap;
  gap: 0.8rem;
  margin-top: 2rem;
}

.button {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 3rem;
  padding: 0.75rem 1.1rem;
  border: 1px solid currentColor;
  font-size: 0.87rem;
  font-weight: 720;
  letter-spacing: 0.025em;
  text-decoration: none;
}

.button-primary {
  border-color: var(--accent-light);
  background: var(--accent-light);
  color: var(--ink-deep);
}

.button-primary:hover {
  border-color: var(--paper-bright);
  background: var(--paper-bright);
  color: var(--ink-deep);
}

.button-secondary {
  color: var(--paper-bright);
}

.button-secondary:hover {
  border-color: var(--accent-light);
  color: var(--accent-light);
}

.hero-figure {
  margin: 0;
  animation: enter 800ms 100ms ease-out both;
}

.theorem-map-link {
  position: relative;
  display: block;
  overflow: hidden;
  border: 1px solid var(--line-dark);
  background: var(--ink);
  cursor: zoom-in;
}

.hero-figure img {
  width: 100%;
  height: auto;
  transition: transform 220ms ease;
}

.theorem-map-link:hover img {
  transform: scale(1.012);
}

.map-action {
  position: absolute;
  right: 0.75rem;
  bottom: 0.75rem;
  padding: 0.45rem 0.65rem;
  background: color-mix(in srgb, var(--ink-deep) 92%, transparent);
  color: var(--paper-bright);
  font-size: 0.72rem;
  font-weight: 720;
  letter-spacing: 0.02em;
}

.hero-figure figcaption {
  max-width: 34rem;
  margin-top: 1rem;
  color: var(--muted-light);
  font-size: 0.78rem;
  letter-spacing: 0.02em;
}

.research-map-section {
  scroll-margin-top: 5.5rem;
  width: min(calc(100% - 2.5rem), var(--measure));
  margin-inline: auto;
  padding: clamp(4.5rem, 8vw, 8rem) 0;
}

.research-map-intro {
  display: grid;
  grid-template-columns: minmax(0, 0.95fr) minmax(18rem, 0.55fr);
  gap: 1.5rem clamp(2rem, 8vw, 7rem);
  align-items: end;
  margin-bottom: clamp(2.2rem, 5vw, 4rem);
}

.research-map-intro .eyebrow,
.research-map-intro h2 {
  grid-column: 1;
}

.research-map-intro h2 {
  max-width: 15ch;
  margin-bottom: 0;
}

.research-map-intro > p:last-child {
  grid-column: 2;
  grid-row: 1 / span 2;
  align-self: end;
  margin-bottom: 0.35rem;
  color: var(--muted);
}

.proof-lab {
  border: 1px solid var(--line-dark);
  background: var(--ink-deep);
  color: var(--paper-bright);
  box-shadow: 0 1.4rem 4rem rgb(11 23 43 / 0.15);
}

.proof-lab-tabs {
  display: grid;
  grid-template-columns: repeat(5, minmax(0, 1fr));
  border-bottom: 1px solid var(--line-dark);
}

.proof-lab-tabs button {
  min-height: 3.75rem;
  padding: 0.8rem 1rem;
  border: 0;
  border-right: 1px solid var(--line-dark);
  background: transparent;
  color: var(--muted-light);
  font: 680 0.76rem/1.3 var(--sans);
  letter-spacing: 0.04em;
  text-align: left;
  text-transform: uppercase;
  cursor: pointer;
}

.proof-lab-tabs button:last-child {
  border-right: 0;
}

.proof-lab-tabs button:hover {
  color: var(--paper-bright);
}

.proof-lab-tabs button[aria-selected="true"] {
  background: var(--accent-light);
  color: var(--ink-deep);
}

.proof-lab-display {
  display: grid;
  grid-template-columns: minmax(0, 1.55fr) minmax(18rem, 0.75fr);
  min-height: 30rem;
}

.proof-route {
  align-self: center;
  width: 100%;
  overflow: visible;
}

.proof-route-mobile {
  display: none;
}

.proof-edge {
  fill: none;
  stroke: var(--accent-light);
  stroke-width: 2.5;
  stroke-dasharray: 8 9;
  marker-end: url("#route-arrow");
  animation: route-flow 1.8s linear infinite;
}

#route-arrow path {
  fill: var(--accent-light);
}

.proof-node rect {
  fill: var(--ink);
  stroke: var(--line-dark);
  stroke-width: 1.5;
}

.proof-node-endpoint rect {
  fill: var(--accent-light);
  stroke: var(--accent-light);
}

.proof-node text {
  font-family: var(--sans);
}

.proof-node-step {
  fill: var(--muted-light);
  font-size: 10px;
  font-weight: 750;
  letter-spacing: 0.08em;
}

.proof-node-label {
  fill: var(--paper-bright);
  font-family: var(--serif);
  font-size: 16px;
  font-weight: 650;
}

.proof-node-detail {
  fill: var(--muted-light);
  font-size: 10.5px;
}

.proof-node-endpoint .proof-node-step,
.proof-node-endpoint .proof-node-label,
.proof-node-endpoint .proof-node-detail {
  fill: var(--ink-deep);
}

.proof-route-panel {
  padding: clamp(2rem, 4vw, 3.5rem);
  border-left: 1px solid var(--line-dark);
  background: var(--ink);
}

.proof-route-panel .status {
  color: var(--accent-light);
}

.proof-route-panel h3 {
  margin-bottom: 1rem;
  color: var(--paper-bright);
  font-size: clamp(1.65rem, 2.5vw, 2.35rem);
}

.proof-route-panel > p:not(.status) {
  color: #d8dfeb;
}

.proof-route-panel dl {
  margin: 2rem 0;
  padding-block: 0.9rem;
  border-block: 1px solid var(--line-dark);
}

.proof-route-panel dl > div {
  display: grid;
  grid-template-columns: 5.4rem 1fr;
  gap: 1rem;
  padding-block: 0.55rem;
}

.proof-route-panel dt {
  color: var(--muted-light);
  font-size: 0.68rem;
  font-weight: 750;
  letter-spacing: 0.08em;
  text-transform: uppercase;
}

.proof-route-panel dd {
  margin: 0;
  color: var(--paper-bright);
  font-size: 0.82rem;
}

.proof-route-panel .text-link {
  color: var(--accent-light);
}

.noscript-note {
  padding: 1rem;
  border: 1px solid var(--line);
}

.overview-film {
  scroll-margin-top: 5.5rem;
  display: grid;
  grid-template-columns: minmax(17rem, 0.55fr) minmax(0, 1.45fr);
  gap: clamp(2rem, 7vw, 6rem);
  align-items: center;
  width: min(calc(100% - 2.5rem), var(--measure));
  margin: 0 auto clamp(4.5rem, 8vw, 8rem);
  padding: clamp(2rem, 5vw, 4rem);
  background: var(--ink-deep);
  color: var(--paper-bright);
}

.overview-film-copy h2 {
  margin-bottom: 1rem;
  font-size: clamp(2.2rem, 4vw, 3.7rem);
}

.overview-film-copy > p:not(.eyebrow) {
  color: #d8dfeb;
}

.overview-film-copy .text-link {
  color: var(--accent-light);
}

.overview-film figure {
  min-width: 0;
  margin: 0;
}

.overview-film video {
  display: block;
  width: 100%;
  height: auto;
  aspect-ratio: 16 / 9;
  object-fit: contain;
  border: 1px solid var(--line-dark);
  background: #08111e;
}

.overview-film figcaption {
  margin-top: 0.75rem;
  color: var(--muted-light);
  font-size: 0.75rem;
}

@keyframes route-flow {
  to {
    stroke-dashoffset: -34;
  }
}

.proof-key,
.section,
.reader-intro,
.reader-section,
.site-footer {
  width: min(calc(100% - 2.5rem), var(--measure));
  margin-inline: auto;
}

.proof-key {
  padding: clamp(3rem, 6vw, 5rem) 0;
  border-bottom: 1px solid var(--line);
}

.proof-key h2 {
  margin-bottom: 1.8rem;
  font-family: var(--sans);
  font-size: 0.82rem;
  font-weight: 750;
  letter-spacing: 0.12em;
  text-transform: uppercase;
}

.proof-key dl {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(13rem, 1fr));
  gap: 1.8rem;
  margin: 0;
}

.proof-key dl > div {
  padding-top: 1rem;
  border-top: 3px solid var(--ink);
}

.proof-key dt {
  font-weight: 760;
}

.proof-key dd {
  margin: 0.4rem 0 0;
  color: var(--muted);
  font-size: 0.88rem;
}

.section {
  padding: clamp(4.5rem, 8vw, 8rem) 0;
}

.section-heading {
  max-width: 56rem;
  margin-bottom: clamp(2.5rem, 5vw, 4.5rem);
}

.section-heading h2 {
  margin-bottom: 1.2rem;
}

.section-heading > p:last-child {
  max-width: 48rem;
  color: var(--muted);
  font-size: 1.05rem;
}

.research-family {
  display: grid;
  grid-template-columns: 4rem minmax(0, 1fr) minmax(11rem, 15rem);
  gap: clamp(1rem, 3vw, 2.5rem);
  align-items: start;
  padding: 2.4rem 0;
  border-top: 1px solid var(--line);
}

.research-family:last-child {
  border-bottom: 1px solid var(--line);
}

.research-family-number {
  color: var(--accent);
  font-family: var(--mono);
  font-size: 0.86rem;
}

.research-family h3 {
  margin-bottom: 0.75rem;
}

.research-family p:not(.status) {
  max-width: 48rem;
  margin-bottom: 0;
  color: var(--muted);
}

.text-link {
  align-self: center;
  font-size: 0.88rem;
  font-weight: 720;
}

.endpoint-section {
  width: 100%;
  max-width: none;
  padding-inline: max(1.25rem, calc((100vw - var(--measure)) / 2));
  background: var(--paper-bright);
}

.endpoint-list {
  margin: 0;
  padding: 0;
  list-style: none;
  counter-reset: none;
}

.endpoint-list > li {
  display: grid;
  grid-template-columns: 4rem minmax(0, 1fr);
  gap: clamp(1rem, 3vw, 2.5rem);
  padding: 2.4rem 0;
  border-top: 1px solid var(--line);
}

.endpoint-list > li:last-child {
  border-bottom: 1px solid var(--line);
}

.endpoint-index {
  display: grid;
  width: 2rem;
  height: 2rem;
  place-items: center;
  border: 1px solid var(--ink);
  font-family: var(--mono);
  font-size: 0.78rem;
}

.endpoint-body h3 {
  max-width: 57rem;
  margin-bottom: 0.85rem;
  font-family: var(--mono);
  font-size: clamp(1rem, 1.7vw, 1.24rem);
  line-height: 1.35;
}

.endpoint-body > p:not(.status) {
  max-width: 57rem;
}

.boundary {
  margin-bottom: 0;
  color: var(--muted);
  font-size: 0.91rem;
}

.boundary strong {
  color: var(--warning);
}

.readers {
  padding-bottom: clamp(5rem, 9vw, 9rem);
}

.reader-links {
  border-top: 1px solid var(--ink);
}

.reader-links > a {
  display: grid;
  grid-template-columns: minmax(12rem, 0.45fr) minmax(0, 1fr);
  gap: 1rem;
  padding: 1.35rem 0;
  border-bottom: 1px solid var(--line);
  text-decoration: none;
  transition: color 160ms ease, padding-left 160ms ease;
}

.reader-links > a:hover {
  padding-left: 0.55rem;
}

.reader-links span {
  font-family: var(--serif);
  font-size: 1.35rem;
  font-weight: 650;
}

.reader-links small {
  align-self: center;
  color: var(--muted);
  font-size: 0.9rem;
}

.closing {
  padding: clamp(4.5rem, 8vw, 7rem) max(1.25rem, calc((100vw - var(--measure)) / 2));
  background: var(--ink);
  color: var(--paper-bright);
}

.closing h2 {
  max-width: 17ch;
}

.site-footer {
  display: flex;
  justify-content: space-between;
  gap: 2rem;
  padding: 2rem 0 3rem;
  color: var(--muted);
  font-size: 0.78rem;
}

.site-footer p {
  margin: 0;
}

.site-footer p:last-child {
  max-width: 46rem;
  text-align: right;
}

/* Reader routes */
.reader-hero {
  padding: clamp(4.5rem, 9vw, 8rem) max(1.25rem, calc((100vw - var(--measure)) / 2));
  background: var(--ink-deep);
  color: var(--paper-bright);
}

.reader-hero .eyebrow {
  color: var(--accent-light);
}

.reader-hero h1 {
  max-width: 13ch;
  margin-bottom: 1.4rem;
  font-size: clamp(2.7rem, 6vw, 5.4rem);
}

.reader-hero p:last-child {
  max-width: 46rem;
  margin-bottom: 0;
  color: #d8dfeb;
  font-size: 1.1rem;
}

.reader-intro {
  display: grid;
  grid-template-columns: 0.34fr minmax(0, 1fr);
  gap: clamp(2rem, 7vw, 7rem);
  padding: clamp(3.5rem, 7vw, 6rem) 0;
  border-bottom: 1px solid var(--line);
}

.reader-intro h2,
.reader-section h2 {
  font-size: clamp(1.7rem, 3vw, 2.6rem);
}

.reader-intro .reading,
.reader-section .reading {
  max-width: var(--reading);
}

.reader-intro ul,
.reader-section ul {
  padding-left: 1.2rem;
}

.reader-intro li + li,
.reader-section li + li {
  margin-top: 0.65rem;
}

.reader-section {
  display: grid;
  grid-template-columns: 0.34fr minmax(0, 1fr);
  gap: clamp(2rem, 7vw, 7rem);
  padding: clamp(3.5rem, 7vw, 6rem) 0;
  border-bottom: 1px solid var(--line);
}

.route-list {
  margin: 0;
  padding: 0;
  list-style: none;
}

.route-list li {
  padding: 1.15rem 0;
  border-top: 1px solid var(--line);
}

.route-list li:last-child {
  border-bottom: 1px solid var(--line);
}

.route-list a {
  font-weight: 720;
}

.route-list p {
  margin: 0.4rem 0 0;
  color: var(--muted);
  font-size: 0.9rem;
}

.callout {
  margin-top: 1.5rem;
  padding: 1.2rem 1.35rem;
  border-left: 3px solid var(--accent);
  background: var(--paper-bright);
}

.callout p:last-child {
  margin-bottom: 0;
}

.reader-next {
  width: min(calc(100% - 2.5rem), var(--measure));
  margin: clamp(4rem, 8vw, 7rem) auto;
  padding: clamp(2rem, 5vw, 4rem);
  background: var(--ink);
  color: var(--paper-bright);
}

.reader-next h2 {
  max-width: 19ch;
  margin-bottom: 1rem;
}

.reader-next p {
  max-width: 46rem;
  color: #d8dfeb;
}

@keyframes enter {
  from {
    opacity: 0;
    transform: translateY(1rem);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

@media (max-width: 1040px) {
  .hero {
    grid-template-columns: 1fr;
    min-height: auto;
  }

  .hero-figure {
    width: 100%;
    max-width: 46rem;
  }

  .proof-lab-display {
    grid-template-columns: 1fr;
  }

  .overview-film {
    grid-template-columns: 1fr;
  }

  .proof-route-panel {
    border-top: 1px solid var(--line-dark);
    border-left: 0;
  }
}

@media (max-width: 860px) {
  .site-header {
    position: static;
    align-items: flex-start;
  }

  .site-header nav {
    max-width: 25rem;
  }

  .proof-key dl {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }

  .research-map-intro {
    grid-template-columns: 1fr;
  }

  .research-map-intro .eyebrow,
  .research-map-intro h2,
  .research-map-intro > p:last-child {
    grid-column: 1;
    grid-row: auto;
  }

  .research-map-intro > p:last-child {
    max-width: 44rem;
  }

  .research-family {
    grid-template-columns: 3rem minmax(0, 1fr);
  }

  .research-family .text-link {
    grid-column: 2;
  }

  .reader-intro,
  .reader-section {
    grid-template-columns: 1fr;
    gap: 1.4rem;
  }

  .site-footer {
    display: block;
  }

  .site-footer p:last-child {
    margin-top: 0.8rem;
    text-align: left;
  }
}

@media (max-width: 590px) {
  .site-header {
    display: block;
  }

  .site-header nav {
    display: grid;
    grid-template-columns: repeat(2, minmax(0, 1fr));
    justify-content: stretch;
    gap: 0.2rem 0.8rem;
    width: 100%;
    margin-top: 0.55rem;
  }

  .site-header nav a {
    display: flex;
    align-items: center;
    min-height: 2.75rem;
    font-size: 0.78rem;
  }

  .hero {
    padding-top: 4.5rem;
  }

  .proof-lab-tabs {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }

  .proof-lab-tabs button:nth-child(2),
  .proof-lab-tabs button:nth-child(4) {
    border-right: 0;
  }

  .proof-lab-tabs button:nth-child(-n + 4) {
    border-bottom: 1px solid var(--line-dark);
  }

  .proof-lab-tabs button:last-child {
    grid-column: 1 / -1;
  }

  .proof-route {
    display: none;
  }

  .proof-route-mobile {
    display: grid;
    gap: 0;
    margin: 0;
    padding: 1.5rem;
    list-style: none;
  }

  .proof-route-mobile li {
    position: relative;
    display: grid;
    gap: 0.15rem;
    min-height: 5.7rem;
    padding: 1rem 1rem 1rem 3.25rem;
    border: 1px solid var(--line-dark);
    background: var(--ink);
  }

  .proof-route-mobile li:not(:last-child) {
    border-bottom: 0;
  }

  .proof-route-mobile li:not(:last-child)::after {
    position: absolute;
    bottom: -0.7rem;
    left: 1.5rem;
    z-index: 1;
    color: var(--accent-light);
    content: "↓";
    font-size: 1rem;
  }

  .proof-route-mobile li:last-child {
    border-color: var(--accent-light);
    background: var(--accent-light);
    color: var(--ink-deep);
  }

  .proof-route-mobile span {
    color: var(--muted-light);
    font-size: 0.62rem;
    font-weight: 750;
    letter-spacing: 0.09em;
    text-transform: uppercase;
  }

  .proof-route-mobile strong {
    color: var(--paper-bright);
    font-family: var(--serif);
    font-size: 1.15rem;
    line-height: 1.15;
  }

  .proof-route-mobile small {
    color: var(--muted-light);
    font-size: 0.72rem;
  }

  .proof-route-mobile li:last-child span,
  .proof-route-mobile li:last-child strong,
  .proof-route-mobile li:last-child small {
    color: var(--ink-deep);
  }

  .proof-route-panel dl > div {
    grid-template-columns: 1fr;
    gap: 0.2rem;
  }

  .proof-key dl {
    grid-template-columns: 1fr;
  }

  .research-family,
  .endpoint-list > li {
    grid-template-columns: 1fr;
  }

  .research-family .text-link {
    grid-column: 1;
  }

  .reader-links > a {
    grid-template-columns: 1fr;
    gap: 0.2rem;
  }

  .actions {
    display: grid;
  }

  .button {
    width: 100%;
  }
}

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

  *,
  *::before,
  *::after {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
  }
}