:root {
  --ink: #14213d;
  --muted: #5d6678;
  --paper: #f8fafc;
  --white: #ffffff;
  --line: #dfe5ec;
  --blue: #316bb3;
  --blue-dark: #1f4f88;
  --teal: #238b8e;
  --orange: #e8702a;
  --shadow: 0 18px 45px rgba(29, 48, 77, 0.09);
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  margin: 0;
  color: var(--ink);
  background: var(--paper);
  font-family: Inter, ui-sans-serif, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  line-height: 1.65;
}

a { color: var(--blue-dark); }
.hero {
  position: relative;
  overflow: hidden;
  padding: 80px 24px 72px;
  text-align: center;
  background:
    radial-gradient(circle at 20% 15%, rgba(49,107,179,.17), transparent 36%),
    radial-gradient(circle at 83% 18%, rgba(35,139,142,.13), transparent 32%),
    linear-gradient(180deg, #fff 0%, #f3f7fb 100%);
  border-bottom: 1px solid var(--line);
}
.hero::after {
  content: "";
  position: absolute;
  left: 50%; bottom: -180px;
  width: 760px; height: 300px;
  transform: translateX(-50%);
  border: 1px solid rgba(49,107,179,.18);
  border-radius: 50%;
}
.hero-inner { position: relative; z-index: 1; max-width: 1120px; margin: auto; }
.eyebrow {
  margin: 0 0 10px;
  color: var(--blue);
  font-size: .78rem;
  font-weight: 800;
  letter-spacing: .13em;
  text-transform: uppercase;
}
h1, h2, h3 { line-height: 1.18; letter-spacing: -.025em; }
h1 { max-width: 1050px; margin: 0 auto 22px; font-size: clamp(2.35rem, 5vw, 4.8rem); }
h1 span { color: var(--blue); }
h2 { margin: 0 0 22px; font-size: clamp(1.9rem, 3.5vw, 3rem); }
h3 { margin: 0 0 10px; font-size: 1.45rem; }
.lead { max-width: 760px; margin: 0 auto 28px; color: var(--muted); font-size: 1.2rem; }
.authors { display: flex; flex-wrap: wrap; justify-content: center; gap: 5px 22px; font-size: 1.04rem; font-weight: 700; }
.authors sup, .affiliations sup { color: var(--blue); }
.affiliations { margin: 9px auto 24px; color: var(--muted); font-size: .88rem; }
.actions { display: flex; flex-wrap: wrap; justify-content: center; gap: 10px; }
.button {
  display: inline-flex;
  align-items: center;
  min-height: 42px;
  padding: 9px 18px;
  color: white;
  background: var(--ink);
  border: 1px solid var(--ink);
  border-radius: 999px;
  font-size: .9rem;
  font-weight: 750;
  text-decoration: none;
  transition: transform .18s ease, box-shadow .18s ease;
}
a.button:hover { transform: translateY(-2px); box-shadow: 0 8px 20px rgba(20,33,61,.16); }
.button.secondary { color: var(--ink); background: white; border-color: var(--line); }
.button.disabled { color: #7a8392; background: #edf0f4; border-color: #e0e4ea; cursor: default; }

main { overflow: hidden; }
section { max-width: 1180px; margin: 0 auto; padding: 86px 28px; }
.narrow { max-width: 850px; }
.figure-section.first { padding-top: 46px; padding-bottom: 46px; }
.hero-figure, .method-figure, .result-card img {
  display: block;
  width: 100%;
  background: white;
  border: 1px solid var(--line);
  border-radius: 18px;
  box-shadow: var(--shadow);
}
.motion-section { padding-top: 46px; padding-bottom: 46px; }
.section-heading.compact { margin-bottom: 24px; }
.video-grid {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 18px;
}
.video-grid.attention-grid {
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 22px;
}
.video-grid.feature-grid {
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 22px;
}
.video-card {
  overflow: hidden;
  margin: 0;
  background: white;
  border: 1px solid var(--line);
  border-radius: 15px;
  box-shadow: 0 10px 28px rgba(29, 48, 77, 0.08);
}
.video-card video {
  display: block;
  width: 100%;
  aspect-ratio: 16 / 9;
  object-fit: cover;
  background: #111827;
}
.video-card.attention-card video {
  aspect-ratio: 798 / 562;
  object-fit: contain;
  background: #f7f9fc;
}
.video-card.correspondence-card video {
  aspect-ratio: 3 / 1;
  object-fit: contain;
  background: #0d1117;
}
.video-card figcaption {
  padding: 10px 14px 12px;
  color: var(--ink);
  font-size: .9rem;
  font-weight: 700;
}
.method-figure { margin: 0 0 28px; }
.caption { max-width: 990px; margin: 18px auto 0; color: var(--muted); font-size: .93rem; text-align: center; }
.section-heading { max-width: 850px; margin-bottom: 38px; }
.method-grid { display: grid; grid-template-columns: 1.3fr .7fr; gap: 28px; align-items: stretch; }
.method-copy, .principle-card {
  background: var(--white);
  border: 1px solid var(--line);
  border-radius: 18px;
  box-shadow: var(--shadow);
}
.method-copy { padding: 30px 34px; }
.method-copy ol { margin: 0 0 20px; padding-left: 22px; }
.method-copy li { margin: 0 0 13px; }
.principle-card {
  display: flex;
  flex-direction: column;
  justify-content: center;
  padding: 34px;
  color: white;
  background: linear-gradient(145deg, var(--blue-dark), var(--teal));
  border: 0;
}
.principle-card p { margin: 10px 0 0; font-size: 1.35rem; line-height: 1.45; }
.card-label { font-size: .75rem; font-weight: 800; letter-spacing: .12em; text-transform: uppercase; opacity: .75; }
.result-stack { display: grid; gap: 28px; }
.result-card {
  display: grid;
  grid-template-columns: minmax(0, 1.6fr) minmax(260px, .75fr);
  gap: 32px;
  align-items: center;
  padding: 24px;
  background: white;
  border: 1px solid var(--line);
  border-radius: 20px;
}
.result-card.reverse { grid-template-columns: minmax(260px, .75fr) minmax(0, 1.6fr); }
.result-card.reverse img { order: 2; }
.result-card p { margin: 0; color: var(--muted); }
pre {
  overflow-x: auto;
  margin: 0;
  padding: 20px;
  color: #eaf1f9;
  background: #101827;
  border-radius: 12px;
  font-size: .84rem;
  line-height: 1.55;
}
.citation pre { margin-top: 22px; }
footer { padding: 28px; color: var(--muted); border-top: 1px solid var(--line); text-align: center; font-size: .85rem; }

@media (max-width: 800px) {
  .hero { padding-top: 58px; }
  .wide-only { display: none; }
  section { padding: 64px 20px; }
  .method-grid, .result-card, .result-card.reverse { grid-template-columns: 1fr; }
  .video-grid, .video-grid.attention-grid { grid-template-columns: repeat(2, minmax(0, 1fr)); }
  .result-card.reverse img { order: 0; }
}

@media (max-width: 520px) {
  .video-grid, .video-grid.attention-grid { grid-template-columns: 1fr; }
}

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  .button { transition: none; }
}