/* ==========================================================================
   Yunhao Wang · personal site
   Paper-and-ink editorial layout with a lattice motif.
   ========================================================================== */

:root {
  --bg: #f5f3ee;
  --bg-2: #ebe8e0;
  --fg: #15171c;
  --fg-2: #4a4f59;
  --fg-3: #858a93;
  --rule: #dcd7cc;
  --rule-2: #c5bfb2;
  --accent: #0b4a8f;
  --spark: #d4432a;
  --dot: 21, 23, 28;
  --spark-inv: #ff7759;

  --serif: "Newsreader", "Iowan Old Style", "Palatino Linotype", Georgia, serif;
  --sans: "IBM Plex Sans", system-ui, -apple-system, "Segoe UI", Roboto, sans-serif;
  --mono: "IBM Plex Mono", ui-monospace, SFMono-Regular, Menlo, Consolas, monospace;

  --wrap: 1120px;
  --gutter: clamp(16px, 4vw, 40px);
  --bar: 60px;
  color-scheme: light;
}

@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) {
    --bg: #0f1012;
    --bg-2: #18191c;
    --fg: #ecebe6;
    --fg-2: #b1b4bb;
    --fg-3: #7f838c;
    --rule: #2a2c31;
    --rule-2: #3a3d43;
    --accent: #8fb5ef;
    --spark: #ff7759;
    --dot: 236, 235, 230;
    --spark-inv: #c23a20;
    color-scheme: dark;
  }
  :root:not([data-theme="light"]) .icon-moon { display: none; }
  :root:not([data-theme="light"]) .icon-sun { display: block; }
}

:root[data-theme="dark"] {
  --bg: #0f1012;
  --bg-2: #18191c;
  --fg: #ecebe6;
  --fg-2: #b1b4bb;
  --fg-3: #7f838c;
  --rule: #2a2c31;
  --rule-2: #3a3d43;
  --accent: #8fb5ef;
  --spark: #ff7759;
  --dot: 236, 235, 230;
  --spark-inv: #c23a20;
  color-scheme: dark;
}
:root[data-theme="dark"] .icon-moon { display: none; }
:root[data-theme="dark"] .icon-sun { display: block; }

/* ---------- base ---------- */

*, *::before, *::after { box-sizing: border-box; }
[hidden] { display: none !important; }

html { scroll-behavior: smooth; -webkit-text-size-adjust: 100%; }
@media (prefers-reduced-motion: reduce) { html { scroll-behavior: auto; } }

body {
  margin: 0;
  background: var(--bg);
  color: var(--fg);
  font: 400 17px/1.65 var(--sans);
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  text-rendering: optimizeLegibility;
  overflow-x: hidden;
}

a { color: var(--fg); text-decoration: underline; text-decoration-color: var(--rule-2); text-decoration-thickness: 1px; text-underline-offset: 3px; transition: color .15s, text-decoration-color .15s; }
a:hover { color: var(--accent); text-decoration-color: currentColor; }

::selection { background: var(--spark); color: #fff; }

:focus-visible { outline: 2px solid var(--spark); outline-offset: 3px; border-radius: 4px; }

.wrap { max-width: var(--wrap); margin: 0 auto; padding: 0 var(--gutter); }

.skip { position: absolute; left: -9999px; top: 12px; z-index: 100; padding: 8px 14px; background: var(--fg); color: var(--bg); font-family: var(--mono); font-size: 13px; text-decoration: none; }
.skip:focus { left: 16px; }

section, footer { scroll-margin-top: var(--bar); }

/* ---------- top bar ---------- */

.topbar {
  position: sticky; top: 0; z-index: 30;
  background: color-mix(in srgb, var(--bg) 84%, transparent);
  -webkit-backdrop-filter: saturate(1.4) blur(12px);
  backdrop-filter: saturate(1.4) blur(12px);
  border-bottom: 1px solid transparent;
  transition: border-color .25s;
}
.topbar.is-scrolled { border-bottom-color: var(--rule); }
.topbar__inner { display: flex; align-items: center; gap: 20px; height: var(--bar); }

.mark { display: inline-flex; align-items: center; gap: 12px; color: var(--fg); text-decoration: none; }
.mark:hover { color: var(--fg); }
.mark__glyph {
  display: grid; place-items: center;
  width: 34px; height: 34px; border: 1px solid currentColor; border-radius: 50%;
  font: italic 400 17px/1 var(--serif); padding-bottom: 2px;
  transition: background .2s, color .2s;
}
.mark:hover .mark__glyph { background: var(--fg); color: var(--bg); }
.mark__name { font: 500 13px/1 var(--mono); letter-spacing: .02em; }

.nav { margin-left: auto; display: flex; gap: 22px; }
.nav a { position: relative; padding: 6px 0; color: var(--fg-2); font: 400 13px/1 var(--mono); text-decoration: none; }
.nav a:hover, .nav a.is-current { color: var(--fg); }
.nav a::after { content: ""; position: absolute; left: 0; right: 0; bottom: 0; height: 1px; background: var(--spark); transform: scaleX(0); transform-origin: left; transition: transform .25s; }
.nav a.is-current::after { transform: scaleX(1); }

.theme-toggle {
  display: grid; place-items: center; flex: none;
  width: 36px; height: 36px; padding: 0;
  border: 1px solid var(--rule-2); border-radius: 50%;
  background: transparent; color: var(--fg); cursor: pointer;
  transition: border-color .15s, transform .3s;
}
.theme-toggle:hover { border-color: var(--fg); transform: rotate(-20deg); }
.theme-toggle svg { width: 16px; height: 16px; }
.icon-sun { display: none; }

/* ---------- hero ---------- */

.hero {
  position: relative; overflow: hidden;
  padding: clamp(40px, 7vw, 88px) 0 clamp(40px, 6vw, 72px);
}
.lattice {
  position: absolute; inset: 0; width: 100%; height: 100%; pointer-events: none;
  -webkit-mask-image: radial-gradient(ellipse 46% 78% at 76% 50%, #000 40%, transparent 100%);
  mask-image: radial-gradient(ellipse 46% 78% at 76% 50%, #000 40%, transparent 100%);
}
.hero__grid {
  position: relative;
  display: grid; grid-template-columns: minmax(0, 1.32fr) minmax(0, .68fr);
  gap: clamp(32px, 6vw, 88px); align-items: center;
}

.kicker {
  display: flex; align-items: center; gap: 12px; margin: 0 0 22px;
  color: var(--fg-2); font: 500 12.5px/1.2 var(--mono); letter-spacing: .08em; text-transform: uppercase;
}
.kicker::before { content: ""; width: 28px; height: 1px; background: var(--spark); }

.name {
  margin: 0 0 24px;
  font: 400 clamp(2.6rem, 5.6vw, 4.25rem)/1.02 var(--serif);
  letter-spacing: -.022em;
}

.contact__big em { font-style: italic; color: var(--accent); }

.bio { max-width: 37em; margin: 0 0 30px; color: var(--fg-2); }

.links { display: flex; flex-wrap: wrap; gap: 10px; margin: 0 0 30px; padding: 0; list-style: none; }
.btn {
  display: inline-flex; align-items: center; gap: 9px; height: 40px; padding: 0 16px;
  border: 1px solid var(--rule-2); border-radius: 999px;
  background: color-mix(in srgb, var(--bg) 70%, transparent);
  color: var(--fg); font: 400 13px/1 var(--mono); text-decoration: none;
  transition: border-color .15s, background .15s, color .15s;
}
.btn:hover { border-color: var(--fg); color: var(--fg); }
.btn svg { width: 15px; height: 15px; flex: none; }
.btn--solid { background: var(--fg); border-color: var(--fg); color: var(--bg); }
.btn--solid:hover { background: transparent; color: var(--fg); }

.latest {
  display: inline-flex; align-items: center; gap: 12px; max-width: 100%;
  padding: 7px 16px 7px 7px; border: 1px solid var(--rule); border-radius: 999px;
  background: color-mix(in srgb, var(--bg-2) 80%, transparent);
  color: var(--fg-2); font-size: 14.5px; line-height: 1.35; text-decoration: none;
  transition: border-color .15s;
}
.latest:hover { border-color: var(--fg-2); color: var(--fg-2); }
.latest b { color: var(--fg); font-weight: 600; }
.latest__tag {
  flex: none; padding: 4px 9px; border-radius: 999px;
  background: var(--spark); color: #fff;
  font: 500 10.5px/1 var(--mono); letter-spacing: .1em; text-transform: uppercase;
}
.latest__arrow { flex: none; color: var(--fg); transition: transform .2s; }
.latest:hover .latest__arrow { transform: translateX(3px); }

.portrait { justify-self: end; width: min(100%, 340px); margin: 0; }
.portrait__frame { position: relative; padding: 14px; }
.portrait__frame img {
  display: block; width: 100%; height: auto; aspect-ratio: 4 / 5; object-fit: cover;
  background: #111; border-radius: 2px;
}
.tick { position: absolute; width: 18px; height: 18px; border: 0 solid var(--fg); }
.tick--tl { top: 0; left: 0; border-top-width: 1px; border-left-width: 1px; }
.tick--tr { top: 0; right: 0; border-top-width: 1px; border-right-width: 1px; }
.tick--bl { bottom: 0; left: 0; border-bottom-width: 1px; border-left-width: 1px; }
.tick--br { bottom: 0; right: 0; border-bottom-width: 1px; border-right-width: 1px; }
.portrait figcaption { display: flex; gap: 10px; padding: 4px 14px 0; color: var(--fg-3); font: 400 12px/1.4 var(--mono); }
.portrait figcaption span { flex: none; color: var(--spark); }

@media (prefers-reduced-motion: no-preference) {
  .hero__text > *, .portrait { animation: rise .9s cubic-bezier(.2, .7, .2, 1) both; }
  .hero__text > :nth-child(2) { animation-delay: .06s; }
  .hero__text > :nth-child(3) { animation-delay: .12s; }
  .hero__text > :nth-child(4) { animation-delay: .18s; }
  .hero__text > :nth-child(5) { animation-delay: .24s; }
  .hero__text > :nth-child(6) { animation-delay: .30s; }
  .portrait { animation-delay: .15s; }
  .lattice { animation: fade 1.6s .2s ease both; }
}
@keyframes rise { from { opacity: 0; transform: translateY(14px); } to { opacity: 1; transform: none; } }
@keyframes fade { from { opacity: 0; } to { opacity: 1; } }

/* ---------- research overview ---------- */

.overview { padding: 0 0 clamp(56px, 8vw, 96px); border-bottom: 1px solid var(--rule); }
.overview__grid {
  display: grid; grid-template-columns: 150px minmax(0, 1fr); gap: 32px;
}
.overview__grid::before {
  content: ""; grid-column: 1 / -1; height: 1px; margin-bottom: clamp(4px, 1vw, 12px); background: var(--rule);
}
.overview__label {
  margin: 0; padding-top: .55em; color: var(--spark);
  font: 500 12.5px/1.2 var(--mono); letter-spacing: .08em; text-transform: uppercase;
}
.overview__text {
  max-width: 34em; margin: 0;
  font: 400 clamp(1.18rem, 1.75vw, 1.42rem)/1.55 var(--serif); letter-spacing: -.005em;
}

/* ---------- sections ---------- */

.section { padding: clamp(64px, 9vw, 112px) 0; border-bottom: 1px solid var(--rule); }

.sh {
  display: flex; align-items: baseline; gap: 16px;
  margin: 0 0 clamp(28px, 4.5vw, 52px);
  font: 400 clamp(1.95rem, 3.8vw, 2.6rem)/1.05 var(--serif); letter-spacing: -.02em;
}
.sh__no { color: var(--spark); font: 500 13px/1 var(--mono); letter-spacing: .04em; }
.sh__rule { flex: 1; align-self: center; min-width: 24px; height: 1px; background: var(--rule); }
.sh__aside { color: var(--fg-2); font: 400 13px/1 var(--mono); text-decoration: none; white-space: nowrap; }
.sh__aside:hover { color: var(--accent); }

/* publications */

.filters {
  position: sticky; top: var(--bar); z-index: 10;
  display: flex; flex-wrap: wrap; gap: 8px;
  margin: 0 calc(-1 * var(--gutter)) 12px; padding: 12px var(--gutter);
  background: color-mix(in srgb, var(--bg) 88%, transparent);
  -webkit-backdrop-filter: blur(10px);
  backdrop-filter: blur(10px);
}
.chip {
  display: inline-flex; align-items: center; gap: 8px; height: 34px; padding: 0 13px;
  border: 1px solid var(--rule-2); border-radius: 999px;
  background: transparent; color: var(--fg-2); cursor: pointer;
  font: 400 13px/1 var(--mono); white-space: nowrap;
  transition: background .15s, color .15s, border-color .15s;
}
.chip span { color: var(--fg-3); font-size: 11px; }
.chip:hover { border-color: var(--fg-2); color: var(--fg); }
.chip.is-active { background: var(--fg); border-color: var(--fg); color: var(--bg); }
.chip.is-active span { color: color-mix(in srgb, var(--bg) 65%, transparent); }

.pubnote { margin: calc(14px - clamp(28px, 4.5vw, 52px)) 0 20px; color: var(--fg-3); font-size: 14px; }
.dagger { margin-left: 2px; color: var(--spark); font-weight: 600; cursor: help; }
.pubnote .dagger { cursor: auto; }

.year {
  display: grid; grid-template-columns: 150px minmax(0, 1fr); gap: 32px;
  padding-top: 32px; border-top: 1px solid var(--rule);
}
.year__label {
  position: sticky; top: calc(var(--bar) + 72px); align-self: start;
  margin: 0; color: var(--fg-3);
  font: 400 2.4rem/1 var(--serif); letter-spacing: -.02em; font-variant-numeric: lining-nums;
}
.pubs { margin: 0; padding: 0; list-style: none; }
.pub { padding-bottom: 36px; scroll-margin-top: calc(var(--bar) + 72px); }
.pub + .pub { padding-top: 30px; border-top: 1px dashed var(--rule); }
.pub.is-first { padding-top: 0; border-top: 0; }
.pub:target .pub__title { color: var(--accent); }

.pub__meta { display: flex; flex-wrap: wrap; align-items: center; gap: 10px; margin: 0 0 12px; font: 400 12px/1 var(--mono); }
.pub__no { color: var(--fg-3); }
.stamp { padding: 4px 8px; border: 1px solid var(--fg); border-radius: 3px; color: var(--fg); font-weight: 500; letter-spacing: .02em; }
.tag { display: inline-flex; align-items: center; gap: 6px; color: var(--spark); font-size: 11px; letter-spacing: .1em; text-transform: uppercase; }
.tag::before { content: ""; width: 6px; height: 6px; border-radius: 50%; background: currentColor; }

.pub__title { margin: 0 0 8px; font: 500 clamp(1.18rem, 1.7vw, 1.32rem)/1.3 var(--serif); letter-spacing: -.008em; transition: color .2s; }
.pub__title a {
  color: inherit; text-decoration: none;
  background: linear-gradient(currentColor, currentColor) 0 100% / 0 1px no-repeat;
  transition: background-size .35s, color .15s;
}
.pub__title a:hover { color: var(--accent); background-size: 100% 1px; }
.pub__authors { margin: 0 0 2px; color: var(--fg-2); font-size: 15.5px; }
.me { color: var(--fg); font-weight: 600; text-decoration: underline; text-decoration-color: var(--spark); text-decoration-thickness: 1.5px; text-underline-offset: 3px; }
.pub__venue { margin: 0 0 14px; color: var(--fg-3); font-size: 14.5px; font-style: italic; }
.pub__tldr { max-width: 44em; margin: 0 0 14px; padding-left: 14px; border-left: 2px solid var(--rule-2); color: var(--fg-2); font-size: 15px; line-height: 1.6; }
.pub__tldr-label { margin-right: 6px; color: var(--fg-3); font: 500 11.5px/1 var(--mono); letter-spacing: .04em; }
.pub__links { display: flex; flex-wrap: wrap; gap: 6px 18px; margin: 0; padding: 0; list-style: none; font: 400 13px/1.6 var(--mono); }
.pub__links a { color: var(--accent); text-decoration: none; }
.pub__links a:hover { text-decoration: underline; }
.pub__links .muted { color: var(--fg-3); }

/* service */

.service { margin: 0; padding: 0; list-style: none; border-top: 1px solid var(--rule); }
.service > li { display: grid; grid-template-columns: 150px minmax(0, 1fr); gap: 32px; padding: 24px 0; border-bottom: 1px solid var(--rule); }
.service__role { padding-top: 9px; color: var(--fg-3); font: 500 12px/1.3 var(--mono); letter-spacing: .08em; text-transform: uppercase; }
.service__venues { display: flex; flex-wrap: wrap; gap: 10px; margin: 0; padding: 0; list-style: none; }
.service__venues li {
  display: inline-flex; align-items: baseline; gap: 10px;
  padding: 7px 13px; border: 1px solid var(--rule-2); border-radius: 4px;
}
.service > li:first-child .service__venues li { border-color: var(--fg); }
.service__venue { font: 500 1.05rem/1.2 var(--serif); }
.service__years { color: var(--fg-3); font: 400 12.5px/1.2 var(--mono); white-space: nowrap; }

/* background */

.timeline { margin: 0; padding: 0; list-style: none; border-top: 1px solid var(--rule); }
.timeline li { display: grid; grid-template-columns: 150px minmax(0, 1fr); gap: 32px; padding: 26px 0; border-bottom: 1px solid var(--rule); }
.tl__when { padding-top: 9px; color: var(--fg-3); font: 400 13px/1.3 var(--mono); white-space: nowrap; }
.tl__what { margin: 0 0 4px; font: 500 1.3rem/1.3 var(--serif); letter-spacing: -.01em; }
.tl__where { margin: 0; color: var(--fg-2); }

/* ---------- contact / footer (inverted) ---------- */

.contact { padding: clamp(64px, 9vw, 112px) 0 36px; background: var(--fg); color: var(--bg); }
.contact a { color: var(--bg); text-decoration-color: color-mix(in srgb, var(--bg) 40%, transparent); }
.contact a:hover { color: var(--bg); text-decoration-color: var(--spark-inv); }
.contact__kicker { display: flex; gap: 12px; margin: 0 0 22px; font: 500 12.5px/1 var(--mono); letter-spacing: .08em; text-transform: uppercase; opacity: .75; }
.contact__kicker span { color: var(--spark-inv); }
.contact__big { max-width: 15em; margin: 0 0 clamp(40px, 6vw, 64px); font: 400 clamp(1.8rem, 4vw, 2.9rem)/1.12 var(--serif); letter-spacing: -.02em; }
.contact .contact__big em { color: var(--spark-inv); }
.contact__grid {
  display: grid; grid-template-columns: repeat(3, minmax(0, 1fr)); gap: 32px;
  padding-top: 28px; border-top: 1px solid color-mix(in srgb, var(--bg) 22%, transparent);
  font-size: 15.5px; line-height: 1.7;
}
.label { display: block; margin-bottom: 8px; font: 500 11.5px/1 var(--mono); letter-spacing: .1em; text-transform: uppercase; opacity: .55; }
.contact__email { font-family: var(--mono); font-size: 15px; word-break: break-all; }
.copy {
  margin-left: 8px; padding: 3px 9px; border: 1px solid color-mix(in srgb, var(--bg) 35%, transparent); border-radius: 999px;
  background: transparent; color: var(--bg); cursor: pointer; font: 400 11.5px/1.4 var(--mono); vertical-align: 1px;
}
.copy:hover { border-color: var(--bg); }
.colophon { display: flex; flex-wrap: wrap; justify-content: space-between; gap: 8px 24px; margin-top: clamp(56px, 8vw, 88px); font: 400 12px/1.5 var(--mono); opacity: .55; }

/* ---------- 404 ---------- */

.lost { min-height: 100vh; display: grid; place-content: center; gap: 18px; padding: 24px var(--gutter); text-align: center; }
.lost h1 { margin: 0; font: 400 clamp(4rem, 14vw, 7rem)/1 var(--serif); letter-spacing: -.03em; }
.lost p { margin: 0; color: var(--fg-2); }
.lost .btn { justify-self: center; }

/* ---------- responsive ---------- */

@media (max-width: 960px) {
  .year { grid-template-columns: minmax(0, 1fr); gap: 18px; }
  .year__label { position: static; font-size: 2rem; }
  .overview__grid { grid-template-columns: minmax(0, 1fr); gap: 14px; }
  .overview__label { padding-top: 0; }
}

@media (max-width: 900px) {
  .hero__grid { grid-template-columns: minmax(0, 1fr); }
  .portrait { order: -1; justify-self: start; width: min(62%, 260px); }
  .lattice {
    -webkit-mask-image: radial-gradient(ellipse 70% 34% at 30% 22%, #000 30%, transparent 100%);
    mask-image: radial-gradient(ellipse 70% 34% at 30% 22%, #000 30%, transparent 100%);
  }
  .contact__grid { grid-template-columns: minmax(0, 1fr); gap: 24px; }
}

@media (max-width: 640px) {
  body { font-size: 16px; }
  .kicker { gap: 10px; font-size: 11px; letter-spacing: .05em; }
  .kicker::before { width: 20px; }
  .mark__name { display: none; }
  .nav { gap: 16px; }
  .nav a { font-size: 12.5px; }
  .filters { flex-wrap: nowrap; overflow-x: auto; scrollbar-width: none; }
  .filters::-webkit-scrollbar { display: none; }
  .timeline li, .service > li { grid-template-columns: minmax(0, 1fr); gap: 4px; }
  .service > li { gap: 12px; }
  .service__role { padding-top: 0; }
  .tl__when { padding-top: 0; }
  .sh { gap: 12px; }
  .sh__aside { display: none; }
  .latest { border-radius: 16px; align-items: flex-start; }
}

@media (max-width: 560px) {
  .nav__opt { display: none; }
}

@media print {
  .topbar, .lattice, .filters, .theme-toggle, .latest, .copy { display: none !important; }
  .section, .hero { padding: 24px 0; }
  .contact { background: none; color: #000; }
}