styles.css

:root {
  color-scheme: light;

  /* Surfaces — warm off-white paper */
  --bg: #f6f5f1;
  --paper: #ffffff;
  --paper-soft: #fbfaf7;
  --band: #f0efe9;

  /* Ink + text */
  --ink: #1a2233;
  --ink-soft: #2a3346;
  --muted: #626c7e;
  --faint: #8b94a3;
  --line: #e4e2da;
  --line-strong: #d4d2c8;

  /* Cohesive navy accent family */
  --accent: #2d4f8e;
  --accent-strong: #213d72;
  --accent-tint: rgba(45, 79, 142, 0.08);
  --accent-tint-2: rgba(45, 79, 142, 0.14);

  /* Warm amber — reserved for key numbers / stats */
  --warm: #b9712a;
  --warm-tint: rgba(185, 113, 42, 0.1);

  --shadow-sm: 0 1px 2px rgba(26, 34, 51, 0.04), 0 4px 14px rgba(26, 34, 51, 0.05);
  --shadow: 0 12px 34px rgba(26, 34, 51, 0.09);
  --shadow-lg: 0 22px 55px rgba(26, 34, 51, 0.12);
  --radius: 12px;
  --radius-sm: 8px;

  --serif: "Newsreader", Georgia, "Times New Roman", serif;
  --sans: Inter, system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  --mono: "JetBrains Mono", ui-monospace, SFMono-Regular, Menlo, monospace;

  --content: 1080px;
}

* {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  background: var(--bg);
  color: var(--ink);
  font-family: var(--sans);
  font-size: 17px;
  line-height: 1.7;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  text-rendering: optimizeLegibility;
}

a {
  color: inherit;
  text-decoration: none;
}

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

::selection {
  background: var(--accent-tint-2);
}

/* ---------------------------------------------------------------- Hero */

.hero {
  position: relative;
  padding-top: 68px;
  border-bottom: 1px solid var(--line);
  background:
    radial-gradient(1100px 480px at 50% -8%, rgba(45, 79, 142, 0.09), transparent 60%),
    radial-gradient(640px 360px at 88% 4%, rgba(185, 113, 42, 0.07), transparent 55%),
    linear-gradient(180deg, #ffffff 0%, var(--paper-soft) 60%, var(--bg) 100%);
}

.topbar {
  position: fixed;
  top: 0;
  left: 0;
  z-index: 100;
  width: 100%;
  min-height: 62px;
  padding-inline: max(20px, calc((100% - var(--content)) / 2));
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 20px;
  border-bottom: 1px solid rgba(228, 226, 218, 0.8);
  background: rgba(250, 249, 246, 0.82);
  backdrop-filter: saturate(160%) blur(16px);
  -webkit-backdrop-filter: saturate(160%) blur(16px);
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 11px;
  font-family: var(--serif);
  font-weight: 600;
  font-size: 19px;
  letter-spacing: 0.01em;
  color: var(--ink);
}

.brand img {
  width: 30px;
  height: 30px;
  object-fit: contain;
  border-radius: 7px;
}

.navlinks {
  display: flex;
  align-items: center;
  gap: 2px;
  color: var(--muted);
  font-size: 14px;
  font-weight: 500;
}

.navlinks a {
  position: relative;
  padding: 7px 11px;
  border-radius: 7px;
  transition: color 160ms ease, background 160ms ease;
}

.navlinks a:hover {
  color: var(--ink);
  background: rgba(26, 34, 51, 0.05);
}

.navlinks a.is-active {
  color: var(--accent-strong);
}

.navlinks a.is-active::after {
  content: "";
  position: absolute;
  left: 11px;
  right: 11px;
  bottom: 1px;
  height: 2px;
  border-radius: 2px;
  background: var(--accent);
}

.hero-inner {
  width: min(var(--content), calc(100% - 40px));
  margin: 0 auto;
  padding: 70px 0 76px;
  text-align: center;
}

.eyebrow {
  width: fit-content;
  margin: 0 auto 22px;
  padding: 6px 15px;
  border: 1px solid var(--accent-tint-2);
  border-radius: 999px;
  color: var(--accent);
  background: var(--accent-tint);
  font-size: 12px;
  font-weight: 700;
  letter-spacing: 0.07em;
  text-transform: uppercase;
}

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

h1 {
  max-width: 980px;
  margin: 0 auto 18px;
  font-family: var(--serif);
  font-size: clamp(34px, 6vw, 64px);
  font-weight: 500;
  line-height: 1.06;
  letter-spacing: -0.01em;
}

.hero-title {
  max-width: 1000px;
  margin: 0 auto 22px;
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 22px;
  text-align: left;
  font-family: var(--serif);
  font-weight: 500;
  font-size: clamp(26px, 3.3vw, 39px);
  line-height: 1.12;
  letter-spacing: -0.012em;
  color: var(--ink);
}

.hero-title span {
  flex: 0 1 auto;
  max-width: 22em;
}

.hero-title u {
  text-decoration: none;
  color: var(--accent);
  text-underline-offset: 6px;
  text-decoration-line: underline;
  text-decoration-thickness: 2px;
  text-decoration-color: var(--accent-tint-2);
}

.hero-title img {
  flex: 0 0 auto;
  height: 2.24em; /* exactly the two-line title height (2 × line-height) */
  width: auto;
  object-fit: contain;
}

.authors {
  max-width: 880px;
  margin: 0 auto 4px;
  color: var(--accent-strong);
  font-size: clamp(15px, 1.5vw, 17px);
  font-weight: 600;
}

.affiliation {
  margin-bottom: 30px;
  color: var(--muted);
  font-size: 15px;
}

.button-row {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: 11px;
  margin: 0 auto 44px;
}

.pill {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 9px;
  min-height: 44px;
  padding: 10px 20px;
  border: 1px solid var(--ink);
  border-radius: 999px;
  background: var(--ink);
  color: #fff;
  font-weight: 600;
  font-size: 15px;
  letter-spacing: 0.01em;
  box-shadow: var(--shadow-sm);
  transition: transform 160ms ease, box-shadow 160ms ease, background 160ms ease;
}

.pill:hover {
  transform: translateY(-2px);
  background: var(--ink-soft);
  box-shadow: var(--shadow);
}

.icon {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-width: 20px;
  height: 20px;
  padding: 0 4px;
  border-radius: 999px;
  background: rgba(255, 255, 255, 0.16);
  font-size: 11px;
  font-family: var(--mono);
  line-height: 1;
}

.icon i {
  font-size: 14px;
  line-height: 1;
}

.arxiv-icon {
  min-width: 28px;
}

.arxiv-icon .ai {
  font-family: Academicons;
  font-size: 15px;
}

/* --------------------------------------------------------- Hero figure */

.hero-figure {
  --hero-video-width: clamp(552px, 58vw, 752px);
  display: flex;
  gap: 18px;
  align-items: stretch;
  justify-content: center;
  text-align: left;
}

.hero-image-card {
  display: flex;
  align-items: stretch;
  flex: 0 1 var(--hero-video-width);
  overflow: hidden;
}

.hero-video-card {
  aspect-ratio: 431 / 242;
  padding: 0;
  background: #0f172a;
}

.figure-card.hero-image-card img,
.figure-card.hero-image-card video {
  width: 100%;
  height: 100%;
  min-height: 0;
  object-fit: contain;
}

.figure-card.hero-image-card video {
  display: block;
  background: #0f172a;
}

.hero-stats {
  display: grid;
  flex: 0 1 250px;
  grid-template-rows: repeat(3, minmax(0, 1fr));
  gap: 12px;
}

.hero-stats div {
  display: flex;
  flex-direction: column;
  justify-content: center;
  min-height: 0;
  padding: 15px 18px;
  border: 1px solid var(--line);
  border-radius: var(--radius-sm);
  background: var(--paper);
  box-shadow: var(--shadow-sm);
}

.hero-stats strong {
  display: block;
  font-family: var(--serif);
  color: var(--warm);
  font-size: 24px;
  font-weight: 600;
  line-height: 1;
  letter-spacing: -0.01em;
}

.hero-stats span {
  display: block;
  margin-top: 9px;
  color: var(--muted);
  font-weight: 500;
  font-size: 12px;
  line-height: 1.45;
}

/* ---------------------------------------------------------- Hero copy */

.hero-overview {
  margin-top: 46px;
  text-align: left;
}

.hero-overview .lead {
  max-width: none;
  font-size: 17px;
  margin-inline: 0;
}

.hero-overview .lead + .lead {
  margin-top: 16px;
}

/* Subtle, refined emphasis — no filled boxes */
.text-highlight {
  color: var(--accent-strong);
  font-weight: 600;
  box-shadow: inset 0 -0.5em 0 var(--accent-tint);
  border-radius: 1px;
  padding: 0 1px;
}

/* ------------------------------------------------------------ Sections */

.section {
  width: min(var(--content), calc(100% - 40px));
  margin: 0 auto;
  padding: 76px 0;
}

.section + .section {
  border-top: 1px solid var(--line);
}

.visual-band {
  width: 100%;
  padding-inline: max(20px, calc((100% - var(--content)) / 2));
  background: var(--band);
  border-top: 1px solid var(--line-strong);
  border-bottom: 1px solid var(--line-strong);
}

.section-heading {
  display: flex;
  align-items: center;
  gap: 14px;
  margin-bottom: 26px;
}

.section-icon {
  flex: 0 0 auto;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-width: 40px;
  height: 40px;
  padding: 0 9px;
  border-radius: 10px;
  background: var(--ink);
  color: #fff;
  font-family: var(--mono);
  font-size: 14px;
  font-weight: 700;
  box-shadow: var(--shadow-sm);
}

.section-icon-image {
  width: 40px;
  min-width: 40px;
  padding: 0;
  overflow: hidden;
  background: var(--paper);
  border: 1px solid var(--line);
}

.section-icon-image img {
  width: 100%;
  height: 100%;
  object-fit: cover;
}

h2 {
  margin: 0;
  font-family: var(--serif);
  font-size: clamp(25px, 3vw, 35px);
  font-weight: 500;
  line-height: 1.18;
  letter-spacing: -0.01em;
  color: var(--ink);
}

h3 {
  margin-bottom: 8px;
  font-family: var(--serif);
  font-size: 19px;
  font-weight: 600;
  line-height: 1.3;
}

.lead {
  max-width: 900px;
  color: var(--ink-soft);
  font-size: 19px;
  line-height: 1.7;
}

.visual-band > .lead {
  width: 100%;
  max-width: none;
  font-size: 18px;
}

.section > p,
.split p {
  max-width: 860px;
  color: var(--muted);
  font-size: 17px;
}

.section > p + p,
.split p + p {
  margin-top: 4px;
}

.section > .full-width-text {
  width: 100%;
  max-width: none;
}

.results-layout > .full-width-text,
.wide-grid > .full-width-text,
.two-panel > .full-width-text {
  grid-column: 1 / -1;
  width: 100%;
  max-width: none;
}

.section.visual-band > p {
  width: 100%;
  max-width: none;
}

/* --------------------------------------------------------- Desiderata */

.desiderata-layout {
  display: grid;
  grid-template-columns: minmax(0, 7fr) minmax(260px, 3fr);
  gap: 36px;
  align-items: center;
}

.section-copy p,
.section-copy .lead {
  max-width: none;
  color: var(--muted);
  font-size: 17px;
}

.section-copy .lead {
  width: 100%;
}

.section-copy ul.lead {
  margin: 8px 0 18px;
  padding-left: 0;
  list-style: none;
}

.section-copy ul.lead li {
  position: relative;
  padding-left: 26px;
  color: var(--muted);
  font-size: 17px;
}

.section-copy ul.lead li + li {
  margin-top: 12px;
}

.section-copy ul.lead li::before {
  content: "";
  position: absolute;
  left: 4px;
  top: 0.72em;
  width: 7px;
  height: 7px;
  border-radius: 50%;
  background: var(--accent);
}

.side-figure img {
  min-height: 0;
}

.limitation-list {
  max-width: 900px;
  margin: -4px 0 18px;
  padding-left: 24px;
  color: var(--muted);
  font-size: 17px;
}

.limitation-list li + li {
  margin-top: 10px;
}

.limitation-list strong {
  color: var(--ink);
  font-weight: 700;
}

/* ------------------------------------------------------- Grid layouts */

.insight-grid,
.three-panel,
.wide-grid,
.results-layout,
.two-panel,
.page-preview {
  display: grid;
  gap: 18px;
}

.insight-grid {
  grid-template-columns: repeat(3, minmax(0, 1fr));
  margin-top: 28px;
}

.insight-grid article {
  padding: 22px;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: var(--paper);
  box-shadow: var(--shadow-sm);
}

.insight-grid p {
  margin: 0;
  color: var(--muted);
}

.insight-grid ul {
  margin: 0;
  padding-left: 18px;
  color: var(--muted);
}

.insight-grid li + li {
  margin-top: 4px;
}

.three-panel,
.results-layout {
  grid-template-columns: repeat(3, minmax(0, 1fr));
  margin-top: 28px;
}

.paired-figures {
  --paired-figure-height: clamp(220px, 30vw, 360px);
  grid-template-columns: minmax(0, 1.29fr) minmax(0, 2.54fr);
  align-items: stretch;
}

.paired-figures .figure-card {
  display: flex;
  flex-direction: column;
}

.paired-figures img {
  height: var(--paired-figure-height);
  min-height: 0;
  object-fit: contain;
}

.balanced-figures {
  --paired-figure-height: clamp(260px, 34vw, 420px);
  grid-template-columns: repeat(2, minmax(0, 1fr));
}

.wide-grid {
  grid-template-columns: repeat(3, minmax(0, 1fr));
  margin-top: 28px;
}

.wide-grid.single-figure {
  grid-template-columns: 1fr;
}

.two-panel {
  grid-template-columns: repeat(2, minmax(0, 1fr));
  margin-top: 28px;
}

.split {
  display: grid;
  grid-template-columns: minmax(0, 0.9fr) minmax(360px, 1.1fr);
  gap: 38px;
  align-items: center;
}

.full-width-section {
  grid-template-columns: 1fr;
}

.full-width-section > div,
.full-width-section p {
  max-width: none;
}

/* ------------------------------------------------ Hypothesis / takeaway */

.hypothesis-box {
  width: 100%;
  max-width: none;
  margin: 26px 0 0;
  padding: 22px 26px;
  border: 1px solid var(--line-strong);
  border-left: 4px solid var(--accent);
  border-radius: var(--radius-sm);
  background:
    linear-gradient(180deg, rgba(45, 79, 142, 0.05), rgba(45, 79, 142, 0.02));
  color: var(--ink-soft);
  font-size: 17px;
  line-height: 1.65;
  box-shadow: var(--shadow-sm);
}

.section > .hypothesis-box {
  max-width: none;
}

.hypothesis-box strong {
  color: var(--accent-strong);
  font-weight: 700;
}

/* -------------------------------------------------------------- Figures */

.figure-card {
  margin: 0;
  padding: 16px;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: var(--paper);
  box-shadow: var(--shadow);
  transition: transform 200ms ease, box-shadow 200ms ease;
}

.figure-card:hover {
  transform: translateY(-3px);
  box-shadow: var(--shadow-lg);
}

.figure-card.large {
  padding: 18px;
}

.figure-card img {
  width: 100%;
  min-height: 180px;
  object-fit: contain;
  border-radius: 6px;
  background: #fff;
}

figcaption {
  margin-top: 12px;
  padding-top: 11px;
  border-top: 1px solid var(--line);
  color: var(--muted);
  font-size: 13.5px;
  line-height: 1.5;
}

/* ---------------------------------------------------------- Cost model */

.formula {
  margin: 22px 0;
  padding: 18px 20px;
  border-left: 4px solid var(--accent);
  border-radius: var(--radius-sm);
  background: var(--accent-tint);
}

.cost-model {
  grid-column: 1 / -1;
  padding: 0;
  border-left: none;
  background: transparent;
}

.cost-model summary {
  display: inline-flex;
  align-items: center;
  gap: 9px;
  width: fit-content;
  max-width: 100%;
  padding: 11px 18px;
  border: 1px solid var(--accent-tint-2);
  border-radius: 999px;
  color: var(--accent);
  background: var(--paper);
  font-size: 14px;
  font-weight: 600;
  cursor: pointer;
  list-style: none;
  box-shadow: var(--shadow-sm);
  transition: background 160ms ease, border-color 160ms ease;
}

.cost-model summary:hover {
  background: var(--accent-tint);
  border-color: var(--accent);
}

.cost-model summary::-webkit-details-marker {
  display: none;
}

.cost-model summary::after {
  content: "+";
  font-family: var(--mono);
  font-weight: 700;
  font-size: 16px;
}

.cost-model[open] summary {
  margin-bottom: 18px;
}

.cost-model[open] summary::after {
  content: "\2013";
}

.cost-model p {
  margin: 0;
  color: var(--muted);
  font-size: 16px;
  line-height: 1.7;
}

.cost-model p + .cost-equation,
.cost-equation + p {
  margin-top: 16px;
}

.cost-equation {
  padding: 16px 18px;
  border: 1px solid var(--line);
  border-radius: var(--radius-sm);
  background: var(--paper-soft);
  overflow-x: auto;
}

.cost-model .formula-label {
  margin-bottom: 9px;
  color: var(--accent);
  font-size: 12px;
  font-weight: 700;
  letter-spacing: 0.06em;
  text-transform: uppercase;
}

.cost-equation pre {
  margin: 0;
  padding: 0;
  color: var(--ink);
  background: transparent;
  font-family: var(--mono);
  font-size: clamp(12px, 1.35vw, 15px);
  line-height: 1.7;
  white-space: pre;
}

code {
  font-family: var(--mono);
  font-size: 0.92em;
}

/* --------------------------------------------------------- Metric strip */

.metric-strip {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 16px;
  margin-top: 22px;
}

.metric-strip div {
  padding: 22px 20px;
  text-align: center;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: var(--paper);
  box-shadow: var(--shadow-sm);
}

.metric-strip b {
  display: block;
  font-family: var(--serif);
  color: var(--warm);
  font-size: 36px;
  font-weight: 600;
  line-height: 1;
}

.metric-strip span {
  display: block;
  margin-top: 9px;
  color: var(--muted);
  font-weight: 500;
  line-height: 1.4;
}

/* --------------------------------------------------------- Page preview */

.page-preview {
  grid-template-columns: repeat(3, minmax(0, 1fr));
  margin-top: 28px;
}

.page-preview figure {
  margin: 0;
  padding: 10px;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: var(--paper);
  box-shadow: var(--shadow);
}

.page-preview img {
  width: 100%;
  aspect-ratio: 612 / 792;
  object-fit: cover;
  object-position: top center;
  border: 1px solid var(--line);
  border-radius: 6px;
}

/* ------------------------------------------------------------ Citation */

.citation-section {
  padding-bottom: 84px;
}

.codebox {
  position: relative;
  margin-top: 22px;
  border: 1px solid #29303f;
  border-radius: var(--radius);
  background: #161c28;
  overflow: hidden;
  box-shadow: var(--shadow-lg);
}

pre {
  margin: 0;
  padding: 24px;
  overflow-x: auto;
  color: #eef1f7;
  font-family: var(--mono);
  font-size: 13px;
  line-height: 1.7;
}

.copy-button {
  position: absolute;
  top: 12px;
  right: 12px;
  min-height: 34px;
  padding: 7px 14px;
  border: 1px solid rgba(255, 255, 255, 0.18);
  border-radius: 999px;
  background: rgba(255, 255, 255, 0.08);
  color: #fff;
  font: inherit;
  font-size: 12px;
  font-weight: 600;
  cursor: pointer;
  transition: background 160ms ease;
}

.copy-button:hover {
  background: rgba(255, 255, 255, 0.18);
}

/* -------------------------------------------------------------- Footer */

.footer {
  border-top: 1px solid var(--line);
  padding: 30px 16px 40px;
  background: var(--paper-soft);
  color: var(--faint);
  text-align: center;
  font-size: 13.5px;
}

.footer p {
  margin: 0;
}

/* ------------------------------------------------- Scroll reveal (subtle) */

.reveal {
  opacity: 0;
  transform: translateY(16px);
  transition: opacity 620ms cubic-bezier(0.22, 1, 0.36, 1),
    transform 620ms cubic-bezier(0.22, 1, 0.36, 1);
  will-change: opacity, transform;
}

.reveal.is-visible {
  opacity: 1;
  transform: none;
}

@media (prefers-reduced-motion: reduce) {
  .reveal {
    opacity: 1;
    transform: none;
    transition: none;
  }

  .figure-card:hover,
  .pill:hover {
    transform: none;
  }
}

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

@media (max-width: 860px) {
  .hero {
    padding-top: 120px;
  }

  .topbar {
    align-items: flex-start;
    flex-direction: column;
    gap: 8px;
    padding: 14px 18px;
  }

  .navlinks {
    width: 100%;
    overflow-x: auto;
    padding-bottom: 2px;
  }

  .hero-inner {
    padding-top: 46px;
  }

  .hero-title {
    flex-direction: column;
    gap: 12px;
    text-align: center;
  }

  .hero-figure {
    flex-direction: column;
    align-items: stretch;
  }

  .hero-image-card,
  .hero-stats {
    width: 100%;
    height: auto;
  }

  .hero-stats {
    grid-template-rows: none;
  }

  .hero-figure,
  .desiderata-layout,
  .split,
  .insight-grid,
  .three-panel,
  .wide-grid,
  .results-layout,
  .two-panel,
  .page-preview,
  .metric-strip {
    grid-template-columns: 1fr;
  }

  .split {
    gap: 24px;
  }

  .paired-figures {
    --paired-figure-height: auto;
  }

  .section,
  .visual-band {
    padding-top: 54px;
    padding-bottom: 54px;
  }

  .lead {
    font-size: 18px;
  }
}

@media (max-width: 520px) {
  body {
    font-size: 16px;
  }

  .hero-inner,
  .section {
    width: min(100% - 28px, var(--content));
  }

  .visual-band {
    padding-inline: 14px;
  }

  .button-row {
    justify-content: stretch;
  }

  .pill {
    flex: 1 1 calc(50% - 11px);
    padding-inline: 12px;
  }

  .hero-stats strong,
  .metric-strip b {
    font-size: 30px;
  }
}