/* Personal site. Light, quiet. Type, spacing and hairlines follow seal-kaist.github.io's project pages. */

:root {
  --bg: #fbfbf8;
  --fg: #11110f;
  --muted: #41413d;
  --dim: #676761;
  --faint: #8d8d86;
  --line: #e1e1db;
  --line-strong: #cfcfc8;
  --card: #ffffff;
  --link: #245fc2;
  --link-hover: #123f91;
  --accent: #d0642f;
  --ink: #202a37;
  --font-sans: "Geist", system-ui, -apple-system, "Segoe UI", Arial, sans-serif;
  --font-mono: "Geist Mono", ui-monospace, SFMono-Regular, Menlo, monospace;
  --ease: cubic-bezier(0.22, 1, 0.36, 1);
}

* { box-sizing: border-box; }

html {
  scroll-behavior: smooth;
  scroll-padding-top: 90px;
  background: var(--bg);
  color-scheme: light;
}

body {
  margin: 0;
  background: var(--bg);
  color: var(--fg);
  font-family: var(--font-sans);
  font-size: 16px;
  line-height: 1.55;
  -webkit-font-smoothing: antialiased;
  overflow-x: clip;
}

a { color: inherit; text-decoration: none; }
img { max-width: 100%; }

.shell {
  width: min(880px, calc(100% - 48px));
  margin-inline: auto;
}

/* Arrow used by text links */
.link-arrow {
  display: inline-block;
  width: 1.3em;
  height: 1.3em;
  flex: 0 0 auto;
  overflow: visible;
  fill: none;
  stroke: currentColor;
  stroke-width: 1.7;
  stroke-linecap: round;
  stroke-linejoin: round;
}
.link-arrow-shaft {
  opacity: 0;
  transform: scaleX(0);
  transform-origin: 18px 12px;
  transition: opacity 180ms ease, transform 240ms var(--ease);
}
.link-arrow-head {
  transform: translateX(-3px);
  transition: transform 240ms var(--ease);
}
a:hover .link-arrow-shaft,
a:focus-visible .link-arrow-shaft { opacity: 1; transform: scaleX(1); }
a:hover .link-arrow-head,
a:focus-visible .link-arrow-head { transform: translateX(0); }

/* Header */
.site-header {
  position: fixed;
  inset: 0 0 auto;
  z-index: 20;
  display: flex;
  height: 64px;
  align-items: center;
  justify-content: space-between;
  padding: 0 max(24px, calc((100vw - 880px) / 2));
  border-bottom: 1px solid rgb(17 17 15 / 7%);
  background: rgb(251 251 248 / 82%);
  backdrop-filter: blur(16px);
  -webkit-backdrop-filter: blur(16px);
}
.brand {
  font-size: 15px;
  font-weight: 560;
  letter-spacing: -0.02em;
}
.site-nav {
  display: flex;
  align-items: center;
  gap: 26px;
  color: var(--dim);
  font-size: 14px;
}
.site-nav a { transition: color 160ms ease; }
.site-nav a:hover,
.site-nav a:focus-visible,
.site-nav a[aria-current="page"] { color: var(--fg); }

/* Entrance */
.page > .profile,
.page > .page-intro {
  animation: page-enter 820ms var(--ease) both;
  animation-delay: 60ms;
}
@keyframes page-enter {
  from { opacity: 0; transform: translateY(22px); }
  to { opacity: 1; transform: none; }
}
.reveal {
  opacity: 0;
  transform: translateY(22px);
  transition: opacity 720ms var(--ease), transform 820ms var(--ease);
  will-change: opacity, transform;
}
.reveal.is-visible { opacity: 1; transform: none; }

/* Small mono label */
.eyebrow {
  margin: 0;
  color: var(--faint);
  font-family: var(--font-mono);
  font-size: 12px;
  font-weight: 500;
  letter-spacing: 0.1em;
  text-transform: uppercase;
}

/* Links inside running text */
.copy a,
.sub a,
.pub .venue a,
.statement a {
  color: var(--link);
  transition: color 160ms ease;
}
.copy a:hover,
.sub a:hover,
.pub .venue a:hover,
.statement a:hover { color: var(--link-hover); }

/* Profile */
.profile {
  display: flex;
  align-items: center;
  gap: 40px;
  padding: 124px 0 36px;
}
.portrait {
  flex: 0 0 auto;
  width: 196px;
  height: 196px;
  object-fit: cover;
  border-radius: 50%;
  border: 1px solid var(--line);
  background: var(--card);
}
.profile h1 {
  margin: 0;
  font-size: clamp(34px, 4.4vw, 44px);
  font-weight: 460;
  letter-spacing: -0.045em;
  line-height: 1.05;
}
.profile .affil {
  margin: 14px 0 0;
  color: var(--muted);
  font-size: 16.5px;
  line-height: 1.5;
}
.profile .affil span { display: block; }
.inline-links {
  display: flex;
  flex-wrap: wrap;
  gap: 8px 24px;
  margin-top: 20px;
  color: var(--dim);
  font-size: 14px;
}
.inline-links a {
  display: inline-flex;
  align-items: center;
  gap: 5px;
  padding-bottom: 3px;
  border-bottom: 1px solid var(--line-strong);
  transition: color 160ms ease, border-color 160ms ease;
}
.inline-links a:hover { color: var(--fg); border-color: var(--fg); }

/* Statement card */
.statement {
  margin: 0 0 8px;
  padding: 26px 30px;
  border: 1px solid var(--line);
  border-radius: 14px;
  background: var(--card);
}
.statement p {
  margin: 0;
  color: var(--muted);
  font-size: 16.5px;
  line-height: 1.7;
}
.statement p + p { margin-top: 14px; }
.statement strong { color: var(--fg); font-weight: 560; }

/* Sections */
.section { padding: 48px 0 8px; }
.section-head {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  gap: 16px;
  padding-bottom: 12px;
  margin-bottom: 22px;
  border-bottom: 1px solid var(--line-strong);
}
.section-head h2 {
  margin: 0;
  font-size: 25px;
  font-weight: 480;
  letter-spacing: -0.035em;
  line-height: 1.1;
}
.section-head .eyebrow { font-size: 11.5px; }

/* Timeline (education) */
.timeline { margin: 0; padding: 0; list-style: none; }
.timeline li {
  position: relative;
  display: grid;
  grid-template-columns: minmax(0, 1fr) auto;
  gap: 6px 28px;
  padding: 0 0 22px 26px;
}
.timeline li::before {
  content: "";
  position: absolute;
  left: 0;
  top: 7px;
  width: 9px;
  height: 9px;
  border-radius: 50%;
  background: var(--card);
  border: 2px solid var(--ink);
}
.timeline li::after {
  content: "";
  position: absolute;
  left: 4px;
  top: 20px;
  bottom: -4px;
  width: 1px;
  background: var(--line-strong);
}
.timeline li:last-child { padding-bottom: 4px; }
.timeline li:last-child::after { display: none; }
.timeline h3,
.entry h3,
.pub h3,
.honor h3 {
  margin: 0;
  font-size: 17px;
  font-weight: 520;
  letter-spacing: -0.02em;
  line-height: 1.35;
}
.sub {
  margin: 4px 0 0;
  color: var(--dim);
  font-size: 14.5px;
  line-height: 1.55;
}
.when {
  padding-top: 3px;
  color: var(--faint);
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.02em;
  text-align: right;
  white-space: nowrap;
}

/* Entries (experience) */
.entries { margin: 0; }
.entry {
  display: grid;
  grid-template-columns: minmax(0, 1fr) auto;
  gap: 6px 28px;
  padding: 18px 0;
  border-bottom: 1px solid var(--line);
}
.entry:first-child { padding-top: 4px; }
.entry:last-child { border-bottom: 0; }
.entry h3 { font-size: 17.5px; }
.entry ul {
  margin: 10px 0 0;
  padding-left: 18px;
  color: var(--muted);
  font-size: 15px;
  line-height: 1.6;
}
.entry li + li { margin-top: 4px; }

/* Publications */
.pub {
  padding: 18px 0;
  border-bottom: 1px solid var(--line);
}
.pub:first-child { padding-top: 4px; }
.pub:last-child { border-bottom: 0; }
.pub h3 { font-size: 17.5px; }
.pub .authors {
  margin: 6px 0 0;
  color: var(--dim);
  font-size: 14.5px;
  line-height: 1.55;
}
.pub .authors b { color: var(--fg); font-weight: 560; }
.pub .venue {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 8px 10px;
  margin: 10px 0 0;
  color: var(--dim);
  font-size: 13.5px;
}
.pill {
  display: inline-flex;
  align-items: center;
  height: 24px;
  padding: 0 10px;
  border: 1px solid var(--line-strong);
  border-radius: 999px;
  color: var(--muted);
  font-size: 12.5px;
  font-weight: 520;
  letter-spacing: -0.01em;
  white-space: nowrap;
}
.pill.main { border-color: var(--ink); background: var(--ink); color: #fff; }
.pill.accent { border-color: rgb(208 100 47 / 45%); color: var(--accent); background: rgb(208 100 47 / 7%); }
.pub .links {
  display: inline-flex;
  flex-wrap: wrap;
  gap: 14px;
  margin-left: auto;
}
.pub .links a {
  display: inline-flex;
  align-items: center;
  gap: 4px;
  color: var(--link);
  font-size: 13.5px;
  font-weight: 500;
}
.pub .links a:hover { color: var(--link-hover); }

/* Honors */
.honor {
  display: grid;
  grid-template-columns: minmax(0, 1fr) auto;
  gap: 4px 28px;
  padding: 12px 0;
  border-bottom: 1px solid var(--line);
}
.honor:first-child { padding-top: 2px; }
.honor:last-child { border-bottom: 0; }
.honor h3 { font-size: 15.5px; font-weight: 500; }
.honor .sub { font-size: 13.5px; }

/* Text link with arrow */
.text-link {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  margin-top: 18px;
  color: var(--link);
  font-size: 14px;
  font-weight: 500;
  transition: color 160ms ease;
}
.text-link:hover { color: var(--link-hover); }

/* Page intro (Projects) */
.page-intro { padding: 124px 0 28px; }
.page-intro h1 {
  margin: 0;
  font-size: clamp(34px, 4.4vw, 44px);
  font-weight: 460;
  letter-spacing: -0.045em;
  line-height: 1.05;
}
.page-intro p {
  max-width: 640px;
  margin: 14px 0 0;
  color: var(--muted);
  font-size: 16.5px;
  line-height: 1.55;
}

/* Project cards */
.projects-section { padding: 20px 0 20px; }
.proj-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 22px;
}
.proj-card {
  display: flex;
  flex-direction: column;
  overflow: hidden;
  border: 1px solid var(--line);
  border-radius: 14px;
  background: var(--card);
  transition: transform 220ms var(--ease), border-color 220ms ease, box-shadow 220ms ease;
}
.proj-card:hover { transform: translateY(-3px); border-color: var(--line-strong); box-shadow: 0 10px 26px rgb(17 17 15 / 8%); }
.proj-card .visual {
  aspect-ratio: 2 / 1;
  overflow: hidden;
  border-bottom: 1px solid var(--line);
  background: #fff;
}
.proj-card .visual img { display: block; width: 100%; height: 100%; object-fit: cover; }
.proj-card .body { display: flex; flex: 1; flex-direction: column; padding: 16px 18px 18px; }
.proj-card .meta { margin: 0 0 8px; display: flex; flex-wrap: wrap; gap: 6px; }
.proj-card h3 { margin: 0 0 6px; font-size: 16.5px; font-weight: 520; letter-spacing: -0.02em; line-height: 1.3; }
.proj-card .desc { margin: 0; color: var(--muted); font-size: 14px; line-height: 1.55; }
.proj-card .text-link { margin-top: auto; padding-top: 14px; font-size: 13.5px; }

/* Footer */
.site-footer {
  display: flex;
  justify-content: space-between;
  gap: 40px;
  margin-top: 72px;
  padding: 32px 0 44px;
  border-top: 1px solid var(--line);
}
.footer-brand strong { font-size: 14px; font-weight: 560; }
.footer-brand p,
.footer-meta p {
  margin: 4px 0 0;
  color: var(--faint);
  font-size: 12px;
  line-height: 1.5;
}
.footer-meta { text-align: right; }
.footer-meta a:hover { color: var(--fg); }

/* Responsive */
@media (max-width: 720px) {
  .profile { flex-direction: column; align-items: flex-start; gap: 22px; padding-top: 104px; }
  .portrait { width: 140px; height: 140px; }
  .timeline li, .entry, .honor { grid-template-columns: 1fr; gap: 2px; }
  .when { order: -1; padding-top: 0; text-align: left; white-space: normal; }
  .pub .links { margin-left: 0; }
  .site-nav { gap: 16px; font-size: 13px; }
  .site-footer { flex-direction: column; gap: 14px; margin-top: 56px; }
  .footer-meta { text-align: left; }
}
@media (max-width: 620px) {
  .proj-grid { grid-template-columns: 1fr; }
}
@media (prefers-reduced-motion: reduce) {
  .page > .profile, .page > .page-intro { animation: none; }
  .reveal { opacity: 1; transform: none; transition: none; }
  .link-arrow-shaft, .link-arrow-head { transition: none; }
}

/* Separator between different venues */
.pub .venue .sep { color: var(--line-strong); font-size: 15px; line-height: 1; margin: 0 -2px; }

/* Author markers */
.pub .authors .mark { position: relative; top: -0.1em; margin-left: 1px; font-size: 0.72em; line-height: 0; color: var(--fg); }
.section-head .legend { margin: 0; color: var(--faint); font-size: 12.5px; white-space: nowrap; }
.section-head .legend sup { font-size: 0.8em; margin-right: 1px; }

/* Note under a date */
.when .note { display: block; margin-top: 4px; color: var(--faint); font-family: var(--font-sans); font-size: 12.5px; font-style: italic; letter-spacing: 0; }