/* Swiss-grid editorial — Zekang Zhang */
:root {
  --paper: #f5f3ec;
  --ink: #0e0e0c;
  --dim: #6b6962;
  --line: #1a1a18;
  --accent: oklch(0.62 0.18 25);
  --accent-2: oklch(0.62 0.18 220);
  --hairline: rgba(14,14,12,0.18);
}

* { box-sizing: border-box; }
html, body { margin: 0; padding: 0; }
html { scroll-behavior: smooth; }
body {
  font-family: 'Inter Tight', 'Helvetica Neue', Helvetica, Arial, sans-serif;
  background: var(--paper);
  color: var(--ink);
  font-size: 16px;
  line-height: 1.45;
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
}

a { color: inherit; text-decoration: none; border-bottom: 1px solid var(--hairline); transition: border-color .2s, color .2s; }
a:hover { border-color: var(--ink); }
a:focus-visible { outline: 2px solid var(--accent); outline-offset: 2px; border-radius: 2px; }

.static-fallback {
  max-width: 920px;
  margin: 0 auto;
  padding: 48px 28px 80px;
}
.static-fallback h1,
.static-fallback h2 {
  font-weight: 500;
  letter-spacing: 0;
}
.static-fallback h1 {
  font-size: clamp(40px, 8vw, 76px);
  line-height: 0.98;
  margin: 0 0 24px;
}
.static-fallback h2 {
  font-size: 28px;
  margin: 44px 0 16px;
}
.static-fallback p,
.static-fallback li {
  max-width: 68ch;
  font-size: 17px;
  line-height: 1.55;
}

.page {
  position: relative;
  min-height: 100vh;
  padding: 0 56px;
  max-width: 1440px;
  margin: 0 auto;
}

/* Header */
.hdr {
  display: grid;
  grid-template-columns: 1fr auto;
  align-items: start;
  padding: 40px 0 24px;
  border-bottom: 1px solid var(--line);
  position: sticky;
  top: 0;
  background: var(--paper);
  z-index: 50;
  mix-blend-mode: normal;
  overflow: hidden;
}
.hdr-l, .hdr-r { position: relative; z-index: 1; }
.hdr-seal {
  position: absolute;
  right: 40px; top: 50%;
  transform: translateY(-50%);
  display: flex; align-items: center;
  opacity: 0.2;
  z-index: 0;
  pointer-events: none;
  user-select: none;
}
.hdr-seal img { height: 114px; width: auto; display: block; }
.hdr-seal img + img { margin-left: -11px; }
.hdr-l { display: flex; gap: 20px; align-items: flex-start; }
.mark {
  width: 44px; height: 44px;
  border: 1px solid var(--ink);
  display: grid; place-items: center;
  font-family: 'IBM Plex Mono', ui-monospace, monospace;
  font-weight: 600;
  letter-spacing: 0.02em;
}
.meta { font-family: 'IBM Plex Mono', ui-monospace, monospace; font-size: 12px; line-height: 1.5; padding-top: 4px; }
.meta-line.dim { color: var(--dim); }
.hdr-r {
  display: flex; gap: 28px; align-items: center;
  font-family: 'IBM Plex Mono', ui-monospace, monospace;
  font-size: 12px;
  padding-top: 12px;
}
.hdr-r a { border: none; color: var(--dim); position: relative; transition: color .25s; }
.hdr-r a::after {
  content: '';
  position: absolute;
  left: 0; right: 0; bottom: -4px;
  height: 1.5px;
  background: var(--ink);
  transform: scaleX(0);
  transform-origin: left;
  transition: transform .25s cubic-bezier(0.4, 0, 0.2, 1);
}
.hdr-r a:hover { color: var(--ink); }
.hdr-r a:hover::after { transform: scaleX(1); }
.hdr-r a.active { color: var(--ink); }
.hdr-r a.active::after { transform: scaleX(1); background: var(--accent); }

/* Hero — interactive cosmic-structure field */
.hero { position: relative; border-bottom: 1px solid var(--line); overflow: hidden; }
.hero-field { position: absolute; inset: 0; z-index: 0; }
#cosmo { width: 100%; height: 100%; display: block; }
.hero-field::after {
  content: ''; position: absolute; inset: 0; pointer-events: none;
  background: linear-gradient(100deg, var(--paper) 22%, rgba(245,243,236,0.55) 42%, rgba(245,243,236,0.0) 70%);
}
.hero-inner {
  position: relative; z-index: 1; pointer-events: none;
  min-height: 540px; padding: 84px 0 92px;
  display: flex; flex-direction: column; justify-content: center;
}
.hero-inner a { pointer-events: auto; }

/* Hero entrance animation */
@keyframes heroFadeUp {
  from { opacity: 0; transform: translateY(24px); }
  to { opacity: 1; transform: translateY(0); }
}
.hero-tag { animation: heroFadeUp .7s cubic-bezier(0.16, 1, 0.3, 1) .1s both; }
.hero-h { animation: heroFadeUp .7s cubic-bezier(0.16, 1, 0.3, 1) .2s both; }
.hero-lede { animation: heroFadeUp .7s cubic-bezier(0.16, 1, 0.3, 1) .35s both; }

.hero-tag {
  font-family: 'IBM Plex Mono', monospace; font-size: 11px; color: var(--dim);
  display: flex; gap: 10px; align-items: center;
  margin: 0 0 26px; letter-spacing: 0.04em; text-transform: uppercase; white-space: nowrap;
}
.dot { width: 7px; height: 7px; border-radius: 50%; background: var(--accent); }
.hero-h {
  font-family: 'Inter Tight', sans-serif; font-weight: 500;
  font-size: clamp(48px, 7.2vw, 96px); line-height: 0.95; letter-spacing: -0.01em;
  margin: 0; max-width: 13ch; text-wrap: balance;
}
.hl { color: var(--accent); }
.hero-lede {
  max-width: 44ch; font-size: 19px; line-height: 1.55; margin: 30px 0 0;
  color: var(--ink); text-wrap: pretty;
}
.focus-em { color: var(--accent); font-weight: 500; }
.hero-meta {
  display: flex; flex-wrap: wrap; gap: 22px 48px; margin-top: 36px;
  border-top: 1px solid var(--hairline); padding-top: 16px; max-width: 680px;
}
.hero-meta > div { display: flex; flex-direction: column; gap: 5px; }
.hero-meta .v { font-family: 'IBM Plex Mono', monospace; font-size: 13px; }
.hero-meta a.v { color: inherit; border-bottom: 1px solid var(--hairline); }
.lbl {
  font-family: 'IBM Plex Mono', monospace; font-size: 10px;
  letter-spacing: 0.06em; text-transform: uppercase; color: var(--dim);
}
.hero-hint {
  position: absolute; right: 0; bottom: 28px; z-index: 1; pointer-events: none;
  font-family: 'IBM Plex Mono', monospace; font-size: 10px; letter-spacing: 0.06em;
  text-transform: uppercase; color: var(--dim); text-align: right; line-height: 1.5;
}
.hero-hint .k { color: var(--accent); }

/* Scroll reveal */
.reveal {
  opacity: 0;
  transform: translateY(28px);
  transition: opacity .6s cubic-bezier(0.16, 1, 0.3, 1), transform .6s cubic-bezier(0.16, 1, 0.3, 1);
}
.reveal.visible {
  opacity: 1;
  transform: translateY(0);
}

/* Sections */
.sec { padding: 80px 0; border-bottom: 1px solid var(--line); scroll-margin-top: 128px; }
.sec-head {
  display: grid;
  grid-template-columns: 120px 1fr;
  align-items: baseline;
  margin-bottom: 48px;
}
.sec-head .num {
  font-family: 'IBM Plex Mono', monospace; font-size: 12px; color: var(--dim);
  letter-spacing: 0.05em;
}
.sec-head h2 {
  font-family: 'Inter Tight', sans-serif;
  font-weight: 500; font-size: 40px; letter-spacing: 0;
  margin: 0;
}
.sec-body { padding-left: 120px; }
.sec-body.two { display: grid; grid-template-columns: 1.4fr 1fr; gap: 64px; align-items: start; }
.prose p { font-size: 17px; line-height: 1.55; margin: 0 0 18px; max-width: 50ch; text-wrap: pretty; }
.prose p:last-child { margin-bottom: 0; }
.prose strong { font-weight: 600; }
.prose em { font-style: italic; color: var(--dim); }
.sec-body.two.about-layout {
  grid-template-columns: minmax(0, 50ch) minmax(0, 530px);
  column-gap: clamp(40px, 3.2vw, 58px);
  row-gap: 18px;
  align-items: center;
  justify-content: start;
}
.about-prose {
  grid-column: 1;
  grid-row: 1;
}
.about-side {
  grid-column: 2;
  grid-row: 1;
  display: grid;
  grid-template-columns: clamp(220px, 42%, 238px) minmax(246px, 1fr);
  gap: clamp(10px, 1.2vw, 14px);
  align-items: stretch;
  width: min(100%, 530px);
  max-width: 530px;
  justify-self: start;
}
.portrait {
  --portrait-top-crop: 8%;
  margin: 0;
  border: 1px solid var(--line);
  background: rgba(14, 14, 12, 0.04);
  overflow: hidden;
  align-self: start;
  aspect-ratio: 413 / 576;
}
.portrait img {
  display: block;
  width: 100%;
  height: auto;
  min-height: 0;
  object-fit: contain;
  object-position: 50% 0;
  transform: translateY(calc(-1 * var(--portrait-top-crop)));
}
.about-card {
  align-self: stretch;
  justify-content: space-between;
  padding: 18px 20px 16px;
  gap: 0;
  font-size: 11px;
  line-height: 1.35;
}
.about-card .card-row {
  grid-template-columns: 78px minmax(0, 1fr);
  gap: 12px;
}

/* Card */
.card {
  border: 1px solid var(--line);
  padding: 24px 24px 18px;
  font-family: 'IBM Plex Mono', monospace; font-size: 12px;
  display: flex; flex-direction: column; gap: 10px;
  transition: box-shadow .3s, transform .3s;
}
.card:hover {
  box-shadow: 0 4px 20px rgba(14, 14, 12, 0.07);
  transform: translateY(-2px);
}
.card-row { display: grid; grid-template-columns: 88px 1fr; gap: 14px; align-items: baseline; }
.card-row a { border-bottom: 1px solid var(--hairline); }

/* Contact n-body field */
.contact-orbit {
  position: relative;
  min-height: clamp(520px, 56vw, 800px);
  border-top: 1px solid var(--line);
  border-bottom: 1px solid var(--line);
  overflow: hidden;
  display: grid;
  grid-template-columns: minmax(0, 1fr) minmax(420px, 560px);
  gap: clamp(28px, 6vw, 76px);
  align-items: end;
  isolation: isolate;
}
.contact-orbit::before {
  content: "";
  position: absolute;
  inset: 0;
  z-index: 0;
  pointer-events: none;
  background:
    radial-gradient(circle at 70% 34%, rgba(44,82,118,0.09), transparent 29%),
    radial-gradient(circle at 34% 78%, rgba(134,68,44,0.08), transparent 25%),
    linear-gradient(180deg, rgba(245,243,236,0.40), rgba(245,243,236,0.10));
}
#nbody-canvas {
  position: absolute;
  inset: 0;
  z-index: 0;
  width: 100%;
  height: 100%;
  cursor: crosshair;
  touch-action: pan-y;
}
.contact-card {
  position: relative;
  z-index: 1;
  grid-column: 2;
  align-self: end;
  margin: 36px 0;
  background: rgba(245, 243, 236, 0.94);
  padding: 48px 48px 36px;
  font-size: 16px;
  gap: 20px;
}
.contact-card .card-row {
  grid-template-columns: 110px 1fr;
  gap: 20px;
}

/* Projects */
.proj { list-style: none; margin: 0; padding: 0; display: flex; flex-direction: column; }
.proj li {
  display: grid;
  grid-template-columns: 60px minmax(0, 1.35fr) minmax(180px, 0.7fr);
  column-gap: 36px;
  row-gap: 18px;
  padding: 32px 0;
  border-top: 1px solid var(--hairline);
  align-items: start;
  transition: background .3s;
  border-radius: 4px;
  margin: 0 -16px;
  padding-left: 16px;
  padding-right: 16px;
}
.proj li:hover { background: rgba(14, 14, 12, 0.02); }
.proj li:first-child { border-top: none; padding-top: 0; }
.proj-n { font-family: 'IBM Plex Mono', monospace; font-size: 12px; color: var(--dim); padding-top: 4px; }
.proj-body { min-width: 0; }
.proj-body h3 { font-family: 'Inter Tight', sans-serif; font-weight: 500; font-size: 22px; letter-spacing: 0; margin: 0 0 8px; }
.proj-body p { margin: 0 0 12px; max-width: 48ch; color: var(--ink); overflow-wrap: anywhere; }
.proj-fig {
  margin: 0;
  display: flex;
  flex-direction: column;
  gap: 8px;
  align-self: start;
  justify-self: start;
  width: min(100%, 330px);
  min-width: 0;
}
.proj-fig-frame {
  border: 1px solid var(--hairline);
  background:
    linear-gradient(180deg, rgba(14,14,12,0.025), rgba(14,14,12,0.01));
  aspect-ratio: 4 / 3;
  overflow: hidden;
  display: block;
  transition: border-color .3s, box-shadow .3s;
}
.proj li:hover .proj-fig-frame {
  border-color: rgba(14, 14, 12, 0.3);
  box-shadow: 0 2px 12px rgba(14, 14, 12, 0.06);
}
.proj-fig img {
  display: block;
  width: 100%;
  height: 100%;
  object-fit: contain;
  padding: 4px;
  transform: scale(1.12);
  transform-origin: center;
  transition: transform .4s cubic-bezier(0.16, 1, 0.3, 1);
}
.proj li:hover .proj-fig img { transform: scale(1.16); }
.proj-fig figcaption {
  font-family: 'IBM Plex Mono', monospace;
  font-size: 10px;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  color: var(--dim);
}
.tags { display: flex; gap: 8px; flex-wrap: wrap; }
.tags span {
  font-family: 'IBM Plex Mono', monospace; font-size: 10px;
  padding: 4px 8px; border: 1px solid var(--hairline);
  letter-spacing: 0.04em;
  transition: border-color .2s, background .2s, color .2s;
}
.tags span:hover {
  border-color: var(--ink);
  background: var(--ink);
  color: var(--paper);
}
.proj-links {
  display: flex;
  flex-wrap: wrap;
  gap: 10px 18px;
  margin-top: 14px;
  font-family: 'IBM Plex Mono', monospace;
  font-size: 11px;
  letter-spacing: 0.04em;
  text-transform: uppercase;
}
.proj-links a {
  color: var(--dim);
}
.proj-links a:hover {
  color: var(--accent);
  border-color: var(--accent);
}

/* Pubs */
.pubs { list-style: none; margin: 0; padding: 0; }
.pubs li {
  display: grid; grid-template-columns: 120px minmax(0, 1fr);
  gap: 32px;
  padding: 24px 0;
  border-top: 1px solid var(--hairline);
  transition: background .3s;
  border-radius: 4px;
  margin: 0 -16px;
  padding-left: 16px;
  padding-right: 16px;
}
.pubs li:hover { background: rgba(14, 14, 12, 0.02); }
.pubs li:first-child { border-top: none; padding-top: 0; }
.pub-meta { display: flex; flex-direction: column; gap: 4px; font-family: 'IBM Plex Mono', monospace; font-size: 12px; }
.pub-meta .yr { color: var(--dim); }
.pub-meta .venue { font-weight: 600; letter-spacing: 0.04em; text-transform: uppercase; font-size: 11px; }
.pub-body { min-width: 0; }
.pub-title { display: block; font-size: 18px; font-weight: 500; line-height: 1.35; margin-bottom: 8px; border: none; max-width: 60ch; }
.pub-title,
.pub-auth { overflow-wrap: anywhere; }
.pub-title:hover { color: var(--accent); }
.pub-auth { color: var(--dim); font-size: 14px; margin-bottom: 4px; }
.pub-note { font-family: 'IBM Plex Mono', monospace; font-size: 10px; color: var(--accent); letter-spacing: 0.06em; text-transform: uppercase; }

/* CV */
#cv { position: relative; overflow: hidden; min-height: 440px; }
.cv-field { position: absolute; inset: 0; z-index: 0; pointer-events: none; }
.cv-field canvas { width: 100%; height: 100%; display: block; }
.cv-field::after {
  content: ''; position: absolute; inset: 0; pointer-events: none;
  background: linear-gradient(115deg, rgba(245,243,236,0.66) 28%, rgba(245,243,236,0.34) 60%, rgba(245,243,236,0.12) 100%);
}
#cv .sec-head, #cv .sec-body { position: relative; z-index: 1; }
.cv-h { font-family: 'IBM Plex Mono', monospace; font-size: 11px; letter-spacing: 0.08em; text-transform: uppercase; color: var(--dim); margin: 0 0 16px; font-weight: 500; }
.cv { list-style: none; margin: 0; padding: 0; }
.cv li {
  display: grid; grid-template-columns: 110px minmax(0, 1fr);
  gap: 16px;
  padding: 12px 0;
  border-top: 1px solid var(--hairline);
  font-size: 15px;
}
.cv li:first-child { border-top: none; }
.cv-yr { font-family: 'IBM Plex Mono', monospace; font-size: 12px; color: var(--dim); }
.cv li > span:last-child { min-width: 0; overflow-wrap: anywhere; }

/* Footer */
.ft {
  display: grid;
  grid-template-columns: 1fr 1fr 1fr;
  align-items: center;
  padding: 32px 0 56px;
  font-family: 'IBM Plex Mono', monospace; font-size: 11px;
  color: var(--dim);
}
.ft > div:nth-child(2) { text-align: center; }
.ft > div:last-child { text-align: right; }
.ft a { border: none; transition: color .2s; }
.ft a:hover { color: var(--ink); }

.dim { color: var(--dim); }
.small { font-size: 12px; font-family: 'IBM Plex Mono', monospace; }

@media (max-width: 1350px) {
  .sec-body.two.about-layout { grid-template-columns: 1fr; gap: 20px; }
  .about-prose,
  .about-side {
    grid-column: 1;
    grid-row: auto;
  }
  .about-side {
    grid-template-columns: clamp(220px, 42%, 238px) minmax(246px, 1fr);
    width: min(100%, 530px);
    max-width: 530px;
  }
}

@media (max-width: 1100px) {
  .hdr { grid-template-columns: 1fr; gap: 16px; }
  .hdr-r { flex-wrap: wrap; gap: 16px 24px; padding-top: 0; }
  .hero-inner { min-height: 520px; }
  .sec-body.two { grid-template-columns: 1fr; gap: 36px; }
  .about-layout { row-gap: 20px; }
  .about-side {
    grid-template-columns: clamp(220px, 42%, 238px) minmax(246px, 1fr);
    width: min(100%, 530px);
    max-width: 530px;
  }
  .card { padding: 20px 20px 16px; }
  .about-card { padding: 16px 18px 14px; gap: 0; }
  .card-row { grid-template-columns: 78px 1fr; gap: 12px; }
  /* Research: collapse figure under body at narrower widths */
  .proj li {
    grid-template-columns: 60px minmax(0, 1fr);
    column-gap: 32px;
    row-gap: 20px;
  }
  .proj-fig {
    grid-column: 2;
    width: min(100%, 310px);
    max-width: 310px;
  }
}

/* Palettes */
.palette-vermilion { --accent: oklch(0.62 0.18 25); }
.palette-cobalt { --accent: oklch(0.55 0.18 245); }
.palette-mono { --accent: #0e0e0c; }
.palette-mono .hl { color: var(--paper); }
.palette-acid { --accent: oklch(0.85 0.22 130); }

@media (max-width: 800px) {
  .page { padding: 0 24px; }
  .hero-inner { min-height: 460px; padding: 64px 0 80px; }
  .hero-field::after { background: linear-gradient(180deg, rgba(245,243,236,0.88), rgba(245,243,236,0.55)); }
  .hero-lede { max-width: 100%; }
  .hero-hint { position: static; text-align: left; margin-top: 22px; }
  .sec-head { grid-template-columns: 1fr; gap: 8px; }
  .sec-body { padding-left: 0; }
  .sec-body.two { grid-template-columns: 1fr; gap: 32px; }
  .contact-orbit { grid-template-columns: 1fr; min-height: 520px; }
  .contact-card { grid-column: 1; margin: 0 0 28px; padding: 24px 24px 18px; font-size: 12px; gap: 10px; }
  .contact-card .card-row { grid-template-columns: 88px 1fr; gap: 14px; }
  .pubs li, .proj li { grid-template-columns: 1fr; gap: 14px; }
  .proj-fig { grid-column: 1; width: min(100%, 294px); max-width: 294px; }
  .ft { grid-template-columns: 1fr; gap: 8px; text-align: left; }
  .ft > div { text-align: left !important; }
}

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  .reveal { opacity: 1; transform: none; transition: none; }
  .hero-tag, .hero-h, .hero-lede { animation: none; }
  .proj-fig img, .portrait img, .card { transition: none; }
}

@media (max-width: 560px) {
  .about-side {
    grid-template-columns: 1fr;
    width: min(100%, 300px);
  }
  .portrait {
    aspect-ratio: 413 / 570;
  }
  .portrait img {
    height: auto;
    min-height: 0;
    transform: translateY(calc(-1 * var(--portrait-top-crop)));
  }
}