:root {
  --ink: #20242b;
  --muted: #606976;
  --blue: #2859a8;
  --blue-dark: #183f79;
  --light: #f4f6f8;
  --line: #dfe3e8;
  --pku-red: #8c0000;
  --red: var(--pku-red);
  --white: #fff;
  --paper: #fcfcfb;
  --shadow: 0 18px 48px rgba(25, 35, 49, .08);
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  margin: 0;
  color: var(--ink);
  background: var(--paper);
  font-family: Arial, Helvetica, sans-serif;
  font-size: 16px;
  line-height: 1.65;
}
img { max-width: 100%; }
a { color: var(--blue); text-decoration: none; }
.container { width: min(1080px, calc(100% - 40px)); margin: 0 auto; }

.paper-header {
  border-top: 5px solid var(--pku-red);
  background:
    radial-gradient(circle at 50% 0%, rgba(140, 0, 0, .045), transparent 34%),
    linear-gradient(180deg, #fdfafa 0%, #fff 74%);
}
.top-nav {
  width: min(1180px, calc(100% - 40px));
  height: 66px;
  margin: 0 auto;
  display: flex;
  align-items: center;
  justify-content: space-between;
  border-bottom: 1px solid var(--line);
}
.wordmark {
  color: var(--ink);
  font-size: 21px;
  font-weight: 700;
  letter-spacing: -0.04em;
}
.wordmark b { color: var(--red); }
.top-nav div { display: flex; gap: 28px; }
.top-nav div a { color: var(--muted); font-size: 13px; }
.top-nav div a { transition: color .2s ease; }
.top-nav div a:hover { color: var(--pku-red); }

.hero {
  padding: 62px 0 68px;
  text-align: center;
}
.institution-mark {
  width: max-content;
  margin: 0 auto 10px;
  display: flex;
  align-items: center;
  gap: 12px;
  color: var(--ink);
}
.institution-mark img {
  width: 46px;
  height: 46px;
  object-fit: contain;
}
.institution-mark strong {
  color: var(--pku-red);
  font-family: Georgia, "Times New Roman", serif;
  font-size: 17px;
  font-weight: 600;
  letter-spacing: .01em;
}
.publication-meta {
  margin: 0 auto 28px;
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  color: #77716f;
  font-size: 10px;
  font-weight: 600;
  letter-spacing: .1em;
  text-transform: uppercase;
}
.publication-meta::before {
  width: 22px;
  height: 1px;
  margin-right: 3px;
  background: rgba(140,0,0,.52);
  content: "";
}
.publication-meta i { color: #bbb4b1; font-style: normal; }
.publication-meta a {
  color: var(--pku-red);
  font-weight: 700;
  text-underline-offset: 3px;
}
.publication-meta a:hover { text-decoration: underline; }
h1, h2, h3 { line-height: 1.25; }
h1 {
  max-width: 950px;
  margin: 0 auto;
  font-family: Georgia, "Times New Roman", serif;
  font-size: clamp(44px, 6.2vw, 68px);
  font-weight: 500;
  letter-spacing: -0.03em;
}
.subtitle {
  max-width: 850px;
  margin: 18px auto 30px;
  color: var(--muted);
  font-family: Georgia, "Times New Roman", serif;
  font-size: clamp(20px, 2.8vw, 27px);
}
.authors {
  max-width: 1040px;
  margin: 0 auto;
  font-size: 17px;
  font-weight: 700;
  line-height: 1.82;
}
.authors a { color: var(--blue); }
.authors a {
  text-decoration: underline;
  text-decoration-color: rgba(40, 89, 168, .28);
  text-underline-offset: 3px;
}
.authors a:hover { color: var(--pku-red); text-decoration-color: currentColor; }
.authors sup, .affiliation sup, .author-note sup { font-size: .65em; }
.affiliation {
  margin: 7px 0 0;
  display: flex;
  justify-content: center;
  gap: 22px;
  flex-wrap: wrap;
  color: #626b76;
  font-family: Georgia, "Times New Roman", serif;
  font-size: 14px;
}
.author-note { margin: 6px 0 0; color: #8b929b; font-size: 11px; }
.link-row {
  margin-top: 34px;
  display: flex;
  justify-content: center;
  gap: 10px;
  flex-wrap: wrap;
}
.resource {
  min-width: 155px;
  padding: 11px 15px;
  color: #fff;
  background: var(--blue-dark);
  border: 1px solid rgba(255,255,255,.08);
  border-radius: 6px;
  box-shadow: 0 6px 16px rgba(24,63,121,.1);
  font-size: 13px;
  font-weight: 700;
  transition: transform .18s ease, background .18s ease, box-shadow .18s ease;
}
.resource small {
  display: block;
  color: rgba(255,255,255,.65);
  font-size: 9px;
  font-weight: 400;
  text-transform: uppercase;
}
.resource.disabled { cursor: not-allowed; box-shadow: none; opacity: .62; }
.resource .icon { margin-right: 6px; }
.resource:hover:not(.disabled) { background: var(--blue); box-shadow: 0 9px 22px rgba(24,63,121,.16); transform: translateY(-1px); }
.resource.video-link { background: #a9362c; }
.resource.video-link:hover { background: #c14438; }

.core-focus {
  color: white;
  background:
    radial-gradient(circle at 82% 28%, rgba(140,0,0,.16), transparent 28%),
    linear-gradient(120deg, #172231 0%, #1a2637 100%);
  border-top: 1px solid #283548;
  border-bottom: 1px solid #263446;
}
.core-focus-inner {
  padding-top: 52px;
  padding-bottom: 52px;
  display: grid;
  grid-template-columns: minmax(0, 1.3fr) 58px minmax(300px, .7fr);
  gap: 32px;
  align-items: center;
}
.focus-label {
  display: block;
  margin-bottom: 10px;
  color: #aebbd0;
  font-size: 10px;
  font-weight: 700;
  letter-spacing: .14em;
  text-transform: uppercase;
}
.focus-question h2 {
  max-width: 720px;
  margin: 0;
  color: white;
  font-size: clamp(25px, 3vw, 38px);
  font-weight: 500;
  line-height: 1.2;
  text-align: left;
}
.focus-question p,
.focus-solution p {
  margin: 14px 0 0;
  color: #c3ccd8;
  font-size: 14px;
  line-height: 1.65;
}
.focus-flow {
  position: relative;
  height: 1px;
  background: rgba(255,255,255,.22);
  font-size: 0;
}
.focus-flow::after {
  position: absolute;
  top: 50%;
  right: -1px;
  color: #d9a6a6;
  content: "›";
  font-family: Georgia, "Times New Roman", serif;
  font-size: 31px;
  line-height: 1;
  transform: translateY(-53%);
}
.focus-solution {
  padding: 27px 28px;
  background: rgba(255,255,255,.06);
  border: 1px solid rgba(255,255,255,.13);
  border-left: 3px solid #bb3b3b;
  border-radius: 7px;
  box-shadow: 0 16px 36px rgba(0,0,0,.13);
}
.focus-solution .focus-label { color: #e1adad; }
.focus-solution h3 {
  margin: 0;
  color: white;
  font-family: Georgia, "Times New Roman", serif;
  font-size: 23px;
  font-weight: 600;
  line-height: 1.3;
}

.teaser {
  padding: 62px 0 76px;
}
.teaser img, .paper-figure {
  display: block;
  width: 100%;
  padding: 11px;
  background: #fff;
  border: 1px solid var(--line);
  border-radius: 8px;
  box-shadow: var(--shadow);
}
.figure-caption {
  max-width: 920px;
  margin: 20px auto 0;
  color: #535c68;
  font-family: Georgia, "Times New Roman", serif;
  font-size: 15px;
  text-align: center;
}
.prose { max-width: 880px; padding: 78px 0 86px; }
h2 {
  margin: 0 0 26px;
  font-family: Georgia, "Times New Roman", serif;
  font-size: 37px;
  font-weight: 500;
  text-align: center;
}
.prose p { color: #3d4652; font-family: Georgia, "Times New Roman", serif; font-size: 17px; line-height: 1.78; text-align: justify; }

.video-section {
  padding: 78px 0;
  background: #111823;
  color: white;
}
.video-section h2 { color: white; }
.video-section .section-intro { color: #aeb8c7; }
.video-frame {
  position: relative;
  width: min(980px, 100%);
  margin: 0 auto;
  aspect-ratio: 16 / 9;
  overflow: hidden;
  background: #05080d;
  border: 1px solid #303b4b;
  border-radius: 9px;
  box-shadow: 0 24px 70px rgba(0,0,0,.34);
}
.video-frame iframe { width: 100%; height: 100%; border: 0; }
.video-poster {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
  padding: 0;
  overflow: hidden;
  color: white;
  background: #05080d;
  border: 0;
  cursor: pointer;
}
.video-poster img {
  width: 100%;
  height: 100%;
  display: block;
  object-fit: cover;
  transition: transform .45s ease, filter .45s ease;
}
.video-shade {
  position: absolute;
  inset: 0;
  background: linear-gradient(180deg, rgba(3,8,15,.06) 45%, rgba(3,8,15,.74) 100%);
  transition: background .25s ease;
}
.play-button {
  position: absolute;
  top: 50%;
  left: 50%;
  width: 74px;
  height: 52px;
  display: grid;
  place-items: center;
  background: #e62117;
  border-radius: 14px;
  box-shadow: 0 8px 28px rgba(0,0,0,.35);
  transform: translate(-50%, -50%);
  transition: transform .2s ease, background .2s ease;
}
.play-button i {
  width: 0;
  height: 0;
  margin-left: 4px;
  border-top: 9px solid transparent;
  border-bottom: 9px solid transparent;
  border-left: 15px solid white;
}
.video-poster-label {
  position: absolute;
  left: 24px;
  bottom: 20px;
  font-size: 14px;
  font-weight: 700;
  letter-spacing: .01em;
  text-shadow: 0 2px 8px rgba(0,0,0,.65);
}
.video-poster:hover img { transform: scale(1.015); filter: brightness(.92); }
.video-poster:hover .play-button { background: #ff2920; transform: translate(-50%, -50%) scale(1.06); }
.video-poster:focus-visible { outline: 3px solid #b7cfff; outline-offset: -3px; }
.video-poster:focus-visible .play-button { transform: translate(-50%, -50%) scale(1.06); }
.video-fallback { margin: 15px 0 0; color: #8f9aaa; font-size: 12px; text-align: center; }
.video-fallback a { color: #b7cfff; text-decoration: underline; }

.soft-section {
  padding: 82px 0;
  background: #f5f6f7;
  border-top: 1px solid #e9ecef;
  border-bottom: 1px solid #e9ecef;
}
.contribution-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 18px;
}
.contribution-grid article {
  padding: 30px;
  background: white;
  border: 1px solid var(--line);
  border-radius: 8px;
  box-shadow: 0 10px 28px rgba(25,35,49,.045);
}
.number { color: var(--blue); font-family: Georgia, serif; font-size: 28px; }
.contribution-grid h3 { margin: 10px 0; font-family: Georgia, serif; font-size: 20px; }
.contribution-grid p { margin: 0; color: var(--muted); font-size: 14px; }

.paper-section { padding: 88px 0; }
.soft-section .paper-section { padding: 0; }
.section-intro {
  max-width: 760px;
  margin: -13px auto 38px;
  color: var(--muted);
  text-align: center;
}
.method-grid {
  margin-top: 38px;
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 30px;
}
.method-grid h3 { margin: 0 0 10px; font-family: Georgia, serif; font-size: 18px; }
.method-grid article { padding-top: 20px; border-top: 2px solid #dfe4eb; }
.method-grid h3 span {
  width: 26px;
  height: 26px;
  margin-right: 7px;
  display: inline-grid;
  place-items: center;
  color: white;
  background: var(--blue);
  border-radius: 50%;
  font-family: Arial, sans-serif;
  font-size: 12px;
}
.method-grid p { margin: 0; color: var(--muted); font-size: 14px; }

.stats {
  margin: 38px 0;
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  background: white;
  border: 1px solid var(--line);
  border-radius: 8px;
  box-shadow: 0 10px 28px rgba(25,35,49,.045);
  overflow: hidden;
}
.stats div { padding: 22px; text-align: center; border-left: 1px solid var(--line); }
.stats div:first-child { border-left: 0; }
.stats strong { display: block; color: var(--blue-dark); font-family: Georgia, serif; font-size: 35px; }
.stats span { color: var(--muted); font-size: 12px; text-transform: uppercase; letter-spacing: .08em; }
.benchmark-content { display: grid; grid-template-columns: .8fr 1.2fr; gap: 45px; align-items: center; }
.benchmark-content img { padding: 9px; background: white; border: 1px solid var(--line); border-radius: 8px; box-shadow: 0 12px 32px rgba(25,35,49,.06); }
.benchmark-content h3 { margin: 0 0 12px; font-family: Georgia, serif; font-size: 22px; }
.benchmark-content p { color: var(--muted); font-size: 14px; }

.citation-section { max-width: 900px; }
.citation-box { position: relative; }
.citation-box pre {
  margin: 0;
  padding: 26px 82px 26px 28px;
  overflow-x: auto;
  color: #263142;
  background: #f3f5f8;
  border: 1px solid var(--line);
  border-radius: 8px;
  font-family: "SFMono-Regular", Consolas, "Liberation Mono", monospace;
  font-size: 12px;
  line-height: 1.65;
  white-space: pre-wrap;
}
.citation-box button {
  position: absolute;
  z-index: 1;
  top: 12px;
  right: 12px;
  padding: 7px 11px;
  color: #465367;
  background: white;
  border: 1px solid #cfd5dd;
  border-radius: 3px;
  cursor: pointer;
  font-size: 11px;
}
.citation-box button:hover { color: white; background: var(--blue); border-color: var(--blue); }

footer { padding: 32px 0; color: #858c95; background: #252b33; font-size: 12px; }
footer .container { display: flex; justify-content: space-between; gap: 20px; }
footer p { margin: 0; }

@media (max-width: 760px) {
  .top-nav div { display: none; }
  .hero { padding-top: 52px; }
  .institution-mark img { width: 46px; height: 46px; }
  .institution-mark strong { font-size: 16px; }
  .publication-meta { max-width: 310px; flex-wrap: wrap; gap: 6px 8px; line-height: 1.6; }
  .publication-meta::before { display: none; }
  .core-focus-inner { grid-template-columns: 1fr; gap: 20px; padding-top: 36px; padding-bottom: 36px; }
  .focus-flow { display: none; }
  .focus-question h2 { font-size: 28px; }
  .focus-solution { padding: 22px; }
  h1 { font-size: 40px; }
  .subtitle { font-size: 20px; }
  .authors { font-size: 15px; line-height: 1.75; }
  .affiliation { align-items: center; flex-direction: column; gap: 2px; }
  .contribution-grid, .method-grid, .benchmark-content { grid-template-columns: 1fr; }
  .stats { grid-template-columns: repeat(2, 1fr); }
  .stats div:nth-child(3) { border-left: 0; border-top: 1px solid var(--line); }
  .stats div:nth-child(4) { border-top: 1px solid var(--line); }
  .paper-section, .soft-section, .prose { padding-top: 58px; padding-bottom: 58px; }
  h2 { font-size: 31px; }
  .prose p { text-align: left; }
  footer .container { flex-direction: column; text-align: center; }
}