:root {
  --paper: #f5f8fd;
  --paper-deep: #e4ecf8;
  --ink: #14243e;
  --muted: #56677e;
  --blue: #173d78;
  --blue-light: #dde9fb;
  --accent: #245fbd;
  --line: rgba(20, 36, 62, 0.16);
  --display: Georgia, "Times New Roman", "Noto Serif CJK SC", "Songti SC", serif;
  --sans: Inter, ui-sans-serif, system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Microsoft YaHei", sans-serif;
  --max: 1240px;
}

* {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  color: var(--ink);
  background:
    radial-gradient(circle at 84% 5%, rgba(36, 95, 189, 0.08), transparent 27rem),
    var(--paper);
  font-family: var(--sans);
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
}

a {
  color: inherit;
}

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

::selection {
  color: var(--paper);
  background: var(--accent);
}

.skip-link {
  position: fixed;
  top: 0.75rem;
  left: 0.75rem;
  z-index: 100;
  padding: 0.65rem 0.9rem;
  color: white;
  background: var(--blue);
  transform: translateY(-160%);
  transition: transform 160ms ease;
}

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

.site-header {
  position: relative;
  z-index: 20;
  display: grid;
  grid-template-columns: 1fr auto 1fr;
  align-items: center;
  width: min(calc(100% - 3rem), var(--max));
  margin: 0 auto;
  padding: 1.65rem 0;
  border-bottom: 1px solid var(--line);
}

.wordmark {
  display: inline-flex;
  align-items: center;
  gap: 0.75rem;
  width: max-content;
  font-size: 0.76rem;
  font-weight: 700;
  letter-spacing: 0.08em;
  text-decoration: none;
  text-transform: uppercase;
}

.wordmark-symbol {
  display: grid;
  width: 2.25rem;
  height: 2.25rem;
  place-items: center;
  border: 1px solid var(--ink);
  border-radius: 50%;
  font-family: var(--display);
  font-size: 0.72rem;
  letter-spacing: -0.04em;
}

.site-nav {
  display: flex;
  align-items: center;
  gap: clamp(1.2rem, 3vw, 2.6rem);
}

.site-nav a,
.language-toggle {
  position: relative;
  font-family: var(--sans);
  font-size: 0.77rem;
  font-weight: 600;
  letter-spacing: 0.08em;
  text-decoration: none;
  text-transform: uppercase;
}

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

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

.language-toggle {
  justify-self: end;
  padding: 0.45rem 0;
  color: var(--muted);
  background: transparent;
  border: 0;
  cursor: pointer;
}

.language-option.is-active {
  color: var(--accent);
}

.hero {
  display: grid;
  grid-template-columns: minmax(0, 1.03fr) minmax(24rem, 0.97fr);
  align-items: center;
  width: min(calc(100% - 3rem), var(--max));
  min-height: min(780px, calc(100vh - 5.6rem));
  margin: 0 auto;
  padding: 5.5rem 0 6.5rem;
}

.eyebrow {
  margin: 0 0 1.35rem;
  color: var(--accent);
  font-size: 0.73rem;
  font-weight: 700;
  letter-spacing: 0.15em;
  text-transform: uppercase;
}

.hero h1 {
  margin: 0;
  font-family: var(--display);
  font-size: clamp(5rem, 9.6vw, 9.2rem);
  font-weight: 400;
  letter-spacing: -0.075em;
  line-height: 0.8;
}

.hero h1 > span {
  display: block;
}

.hero h1 > span:last-child {
  margin-left: clamp(1.8rem, 5vw, 5.4rem);
}

.accent-dot {
  color: var(--accent);
}

.hero-cn {
  margin: 1.7rem 0 0 clamp(1.8rem, 5vw, 5.4rem);
  color: var(--muted);
  font-family: var(--display);
  font-size: 1.05rem;
  letter-spacing: 0.42em;
}

.hero-intro {
  max-width: 34rem;
  margin: 2.6rem 0 0 clamp(1.8rem, 5vw, 5.4rem);
  font-family: var(--display);
  font-size: clamp(1.25rem, 2vw, 1.7rem);
  line-height: 1.42;
}

.hero-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 0.75rem;
  margin: 2.3rem 0 0 clamp(1.8rem, 5vw, 5.4rem);
}

.button {
  display: inline-flex;
  align-items: center;
  justify-content: space-between;
  min-width: 10.4rem;
  padding: 0.85rem 1.1rem;
  border: 1px solid var(--blue);
  font-size: 0.82rem;
  font-weight: 700;
  letter-spacing: 0.025em;
  text-decoration: none;
  transition: color 180ms ease, background 180ms ease, transform 180ms ease;
}

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

.button-primary {
  color: var(--paper);
  background: var(--blue);
}

.button-primary:hover,
.button-primary:focus-visible {
  background: #2456a0;
}

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

.hero-figure {
  position: relative;
  display: grid;
  place-items: center;
}

.geometry {
  width: min(100%, 37rem);
  overflow: visible;
}

.orbit {
  fill: none;
  stroke: rgba(20, 36, 62, 0.13);
  stroke-width: 1;
  stroke-dasharray: 3 8;
}

.orbit-a {
  transform-origin: 310px 310px;
  animation: spin 34s linear infinite;
}

.orbit-b {
  transform-origin: 310px 310px;
  animation: spin-reverse 25s linear infinite;
}

.curve {
  fill: none;
  stroke-linecap: round;
  stroke-linejoin: round;
}

.curve-a {
  stroke: url(#curve-gradient);
  stroke-width: 2;
}

.curve-b {
  stroke: rgba(36, 95, 189, 0.23);
  stroke-width: 1;
}

.graph-lines line {
  stroke: rgba(23, 61, 120, 0.33);
  stroke-width: 1.2;
}

.graph-nodes circle {
  fill: var(--paper);
  stroke: var(--blue);
  stroke-width: 1.5;
}

.graph-nodes circle:nth-child(3),
.graph-nodes circle:nth-child(6) {
  fill: var(--accent);
  stroke: var(--accent);
}

.geometry text {
  fill: var(--blue);
  font-family: var(--display);
  font-size: 35px;
  font-style: italic;
}

.figure-note {
  position: absolute;
  right: 8%;
  bottom: 11%;
  margin: 0;
  color: var(--muted);
  font-size: 0.66rem;
  font-weight: 700;
  letter-spacing: 0.2em;
  text-transform: uppercase;
  transform: rotate(90deg) translateX(100%);
  transform-origin: right bottom;
}

.section {
  width: min(calc(100% - 3rem), var(--max));
  margin: 0 auto;
  padding: 7.5rem 0;
  border-top: 1px solid var(--line);
}

.section-label {
  display: flex;
  gap: 1.1rem;
  margin-bottom: 4rem;
  color: var(--muted);
  font-size: 0.72rem;
  font-weight: 700;
  letter-spacing: 0.16em;
  text-transform: uppercase;
}

.section-label span:first-child {
  color: var(--accent);
}

.section-title {
  max-width: 50rem;
  margin: 0;
  font-family: var(--display);
  font-size: clamp(2.5rem, 5vw, 5.4rem);
  font-weight: 400;
  letter-spacing: -0.05em;
  line-height: 1.02;
}

.about-grid {
  display: grid;
  grid-template-columns: minmax(0, 1.05fr) minmax(20rem, 0.75fr);
  gap: clamp(4rem, 10vw, 10rem);
  align-items: start;
}

.about-copy {
  max-width: 35rem;
  padding-top: 0.4rem;
}

.about-copy > p {
  margin: 0 0 1.35rem;
  color: #34465f;
  font-family: var(--display);
  font-size: clamp(1.08rem, 1.5vw, 1.3rem);
  line-height: 1.62;
}

.interest-list {
  display: flex;
  flex-wrap: wrap;
  gap: 0.55rem;
  margin: 2.2rem 0 0;
  padding: 0;
  list-style: none;
}

.interest-list li {
  padding: 0.44rem 0.72rem;
  border: 1px solid var(--line);
  border-radius: 999px;
  color: var(--blue);
  font-size: 0.74rem;
  font-weight: 650;
}

.profile-facts {
  margin: 2.4rem 0 0;
  border-top: 1px solid var(--line);
}

.profile-facts > div {
  display: grid;
  grid-template-columns: 5.5rem 1fr;
  gap: 1rem;
  padding: 0.9rem 0;
  border-bottom: 1px solid var(--line);
}

.profile-facts dt {
  color: var(--accent);
  font-size: 0.68rem;
  font-weight: 700;
  letter-spacing: 0.09em;
  text-transform: uppercase;
}

.profile-facts dd {
  margin: 0;
  color: #445671;
  font-size: 0.8rem;
  line-height: 1.5;
}

.section-heading {
  display: flex;
  align-items: end;
  justify-content: space-between;
  gap: 2rem;
  margin-bottom: 3.8rem;
}

.text-link {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  width: max-content;
  color: var(--blue);
  font-size: 0.78rem;
  font-weight: 700;
  text-decoration-color: rgba(23, 61, 120, 0.35);
  text-underline-offset: 0.3rem;
}

.text-link:hover,
.text-link:focus-visible {
  color: var(--accent);
}

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

.paper {
  display: grid;
  grid-template-columns: 3rem minmax(0, 1fr) 6.6rem;
  gap: 2rem;
  padding: 2.35rem 0;
  border-top: 1px solid var(--line);
}

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

.paper-index,
.paper-meta {
  color: var(--muted);
  font-size: 0.68rem;
  font-weight: 650;
  letter-spacing: 0.1em;
  text-transform: uppercase;
}

.paper-index {
  padding-top: 0.25rem;
  color: var(--accent);
  font-family: var(--display);
  font-size: 0.8rem;
}

.paper-meta {
  margin: 0 0 0.65rem;
}

.paper h3 {
  max-width: 49rem;
  margin: 0;
  font-family: var(--display);
  font-size: clamp(1.35rem, 2.4vw, 2.15rem);
  font-weight: 400;
  letter-spacing: -0.025em;
  line-height: 1.2;
}

.paper-authors {
  margin: 0.8rem 0 0;
  color: #445671;
  font-size: 0.84rem;
}

.paper-summary {
  max-width: 43rem;
  margin: 1.05rem 0 0;
  color: var(--muted);
  font-size: 0.88rem;
  line-height: 1.65;
}

.paper-links {
  display: flex;
  flex-direction: column;
  gap: 0.45rem;
  align-items: flex-start;
  padding-top: 0.15rem;
}

.paper-links a {
  font-size: 0.74rem;
  font-weight: 700;
  text-decoration-color: rgba(20, 36, 62, 0.25);
  text-underline-offset: 0.22rem;
}

.paper-links a:hover,
.paper-links a:focus-visible {
  color: var(--accent);
}

.projects-grid {
  display: grid;
  grid-template-columns: minmax(18rem, 0.8fr) minmax(0, 1.2fr);
  gap: clamp(4rem, 10vw, 10rem);
  align-items: start;
}

.projects-intro {
  max-width: 32rem;
  margin: 1.7rem 0 0;
  color: var(--muted);
  font-family: var(--display);
  font-size: 1.15rem;
  line-height: 1.6;
}

.project-card {
  position: relative;
  padding: clamp(2rem, 5vw, 4rem);
  overflow: hidden;
  color: var(--paper);
  background: var(--blue);
}

.project-card .paper-meta {
  position: relative;
  z-index: 1;
  color: #9fcaff;
}

.project-card h3 {
  position: relative;
  z-index: 1;
  max-width: 30rem;
  margin: 1rem 0 0;
  font-family: var(--display);
  font-size: clamp(2rem, 4vw, 3.8rem);
  font-weight: 400;
  letter-spacing: -0.04em;
  line-height: 1.04;
}

.project-card > p:not(.paper-meta) {
  position: relative;
  z-index: 1;
  max-width: 35rem;
  margin: 1.6rem 0 2.4rem;
  color: rgba(245, 248, 253, 0.76);
  font-size: 0.9rem;
  line-height: 1.72;
}

.project-card .button-secondary {
  position: relative;
  z-index: 1;
  color: var(--paper);
  border-color: rgba(245, 248, 253, 0.55);
}

.project-card .button-secondary:hover,
.project-card .button-secondary:focus-visible {
  color: var(--blue);
  background: var(--paper);
}

.project-mark {
  position: absolute;
  top: -4rem;
  right: -4rem;
  width: 20rem;
  height: 20rem;
  opacity: 0.15;
}

.project-mark::before,
.project-mark::after {
  position: absolute;
  inset: 2rem;
  content: "";
  border: 1px solid var(--paper);
  border-radius: 50%;
}

.project-mark::after {
  inset: 5.5rem;
}

.project-mark span {
  position: absolute;
  width: 0.65rem;
  height: 0.65rem;
  background: var(--paper);
  border-radius: 50%;
}

.project-mark span:nth-child(1) { top: 2rem; left: 9.7rem; }
.project-mark span:nth-child(2) { top: 7rem; left: 3rem; }
.project-mark span:nth-child(3) { top: 9.7rem; left: 9.7rem; background: #9fcaff; }
.project-mark span:nth-child(4) { right: 2.6rem; bottom: 6rem; }
.project-mark span:nth-child(5) { bottom: 2rem; left: 8rem; }

.talks-grid {
  display: grid;
  grid-template-columns: minmax(18rem, 0.8fr) minmax(0, 1.2fr);
  gap: clamp(4rem, 10vw, 10rem);
}

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

.talk {
  display: grid;
  grid-template-columns: 7.6rem 1fr;
  gap: 1.6rem;
  padding: 2rem 0;
  border-bottom: 1px solid var(--line);
}

.talk time {
  color: var(--accent);
  font-family: var(--display);
  font-size: 0.86rem;
}

.talk h3 {
  margin: 0;
  font-family: var(--display);
  font-size: 1.3rem;
  font-weight: 400;
  line-height: 1.32;
}

.talk p {
  margin: 0.65rem 0 0.7rem;
  color: var(--muted);
  font-size: 0.82rem;
}

.contact {
  color: var(--paper);
  background: var(--blue);
}

.contact-inner {
  width: min(calc(100% - 3rem), var(--max));
  margin: 0 auto;
  padding: 7.5rem 0 8rem;
}

.contact .eyebrow {
  color: #9fcaff;
}

.contact h2 {
  max-width: 57rem;
  margin: 0;
  font-family: var(--display);
  font-size: clamp(2.7rem, 6vw, 6rem);
  font-weight: 400;
  letter-spacing: -0.055em;
  line-height: 1.02;
}

.contact-email {
  display: inline-block;
  margin-top: 3.6rem;
  font-family: var(--display);
  font-size: clamp(1.15rem, 3vw, 2rem);
  text-decoration-color: rgba(245, 248, 253, 0.42);
  text-underline-offset: 0.42rem;
}

.contact-email:hover,
.contact-email:focus-visible {
  color: #b6d9ff;
}

.contact-links {
  display: flex;
  flex-wrap: wrap;
  gap: 1.7rem;
  margin-top: 4.8rem;
}

.contact-links a {
  color: rgba(245, 248, 253, 0.72);
  font-size: 0.75rem;
  font-weight: 700;
  letter-spacing: 0.08em;
  text-underline-offset: 0.25rem;
  text-transform: uppercase;
}

.contact-links a:hover,
.contact-links a:focus-visible {
  color: white;
}

.site-footer {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 1.5rem max(1.5rem, calc((100vw - var(--max)) / 2));
  color: var(--paper);
  background: #10294f;
  font-size: 0.7rem;
  letter-spacing: 0.07em;
  text-transform: uppercase;
}

.site-footer p {
  margin: 0;
}

.site-footer a {
  text-underline-offset: 0.25rem;
}

.js .reveal {
  opacity: 0;
  transform: translateY(18px);
  transition: opacity 650ms ease, transform 650ms cubic-bezier(0.22, 1, 0.36, 1);
}

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

@keyframes spin {
  to { transform: rotate(360deg); }
}

@keyframes spin-reverse {
  to { transform: rotate(-360deg); }
}

@media (max-width: 900px) {
  .site-header {
    grid-template-columns: 1fr auto;
  }

  .site-nav {
    display: flex;
    grid-column: 1 / -1;
    grid-row: 2;
    flex-wrap: wrap;
    gap: 0.8rem 1.3rem;
    padding-top: 1.25rem;
  }

  .hero {
    grid-template-columns: 1fr;
    min-height: auto;
    padding: 5rem 0 4rem;
  }

  .hero-figure {
    width: min(92%, 34rem);
    margin: 1rem auto 0;
  }

  .about-grid,
  .projects-grid,
  .talks-grid {
    grid-template-columns: 1fr;
    gap: 3rem;
  }

  .about-copy {
    padding: 0;
  }
}

@media (max-width: 650px) {
  .site-header,
  .hero,
  .section,
  .contact-inner {
    width: min(calc(100% - 2rem), var(--max));
  }

  .site-header {
    padding: 1rem 0;
  }

  .wordmark > span:last-child {
    display: none;
  }

  .hero {
    padding-top: 4.5rem;
  }

  .hero h1 {
    font-size: clamp(4.2rem, 22vw, 6.4rem);
  }

  .hero h1 > span:last-child,
  .hero-cn,
  .hero-intro,
  .hero-actions {
    margin-left: 0;
  }

  .hero h1 > span:last-child {
    margin-top: 0.15em;
  }

  .hero-figure {
    width: 108%;
    margin-left: -4%;
  }

  .section {
    padding: 5.2rem 0;
  }

  .section-label {
    margin-bottom: 2.6rem;
  }

  .section-heading {
    align-items: start;
    flex-direction: column;
    margin-bottom: 2.8rem;
  }

  .paper {
    grid-template-columns: 2rem minmax(0, 1fr);
    gap: 1rem;
  }

  .paper-links {
    grid-column: 2;
    flex-direction: row;
    flex-wrap: wrap;
    gap: 1.1rem;
  }

  .talk {
    grid-template-columns: 1fr;
    gap: 0.65rem;
  }

  .contact-inner {
    padding: 5.5rem 0 6rem;
  }

  .contact-email {
    word-break: break-word;
  }

  .site-footer {
    padding-right: 1rem;
    padding-left: 1rem;
  }
}

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

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

/* Blue accents and a compact overview of the preprint list. */
:focus-visible { outline: 2px solid var(--accent); outline-offset: 5px; }
.hero h1, .section-title, .paper h3 { color: var(--blue); }
.papers-intro { max-width: 48rem; margin: -1.5rem 0 2.8rem; color: var(--muted); font-size: 0.95rem; }
.paper-links a { color: var(--blue); }