/* Kaiyu Yang — personal site, 2026 redesign */

:root {
  --bg: #faf9f6;
  --ink: #1d1c19;
  --muted: #6e6a61;
  --faint: #97928a;
  --accent: #175f53;
  --accent-hover: #0c4038;
  --rule: #e5e2da;
  --serif: "Charter", "Bitstream Charter", "Sitka Text", Cambria, Georgia, serif;
  --mono: "SF Mono", "Cascadia Mono", Menlo, Consolas, "Liberation Mono", monospace;
}

* { box-sizing: border-box; }

html {
  -webkit-text-size-adjust: 100%;
}

body {
  margin: 0;
  background: var(--bg);
  color: var(--ink);
  font-family: var(--serif);
  font-size: 1.0625rem;
  line-height: 1.65;
  font-feature-settings: "liga", "kern";
  text-rendering: optimizeLegibility;
}

.page {
  max-width: 50rem;
  margin: 0 auto;
  padding: 4.5rem 1.5rem 3rem;
}

/* the column is sized for lists and grids; running prose keeps a shorter
   reading measure so paragraphs don't stretch past ~75 characters */
section p,
.focus li,
.work .note { max-width: 42.5rem; }

a {
  color: var(--accent);
  text-decoration: none;
  border-bottom: 1px solid color-mix(in srgb, var(--accent) 30%, transparent);
  transition: color 120ms ease, border-color 120ms ease;
}

a:hover {
  color: var(--accent-hover);
  border-bottom-color: var(--accent-hover);
}

::selection { background: #dbe8e2; }

/* ---------- header ---------- */

.masthead {
  display: flex;
  align-items: flex-start;
  justify-content: space-between;
  gap: 1.5rem;
}

.masthead h1 {
  font-size: 2.375rem;
  font-weight: 700;
  letter-spacing: -0.015em;
  line-height: 1.1;
  margin: 0;
}

.masthead .hanzi {
  font-weight: 400;
  color: var(--faint);
  font-size: 1.25rem;
  margin-left: 0.5rem;
  letter-spacing: 0.05em;
}

.role {
  margin: 0.6rem 0 0;
  font-size: 1.0625rem;
  color: var(--muted);
}

.role a { color: inherit; border-bottom-color: color-mix(in srgb, var(--muted) 35%, transparent); }
.role a:hover { color: var(--accent-hover); }

.portrait {
  flex: 0 0 auto;
  width: 7.25rem;
  height: 7.25rem;
  object-fit: cover;
  border-radius: 4px;
  filter: saturate(0.92);
}

/* ---------- contact row ---------- */

.contact {
  margin: 1.75rem 0 0;
  padding: 0;
  list-style: none;
  display: flex;
  flex-wrap: wrap;
  gap: 0.4rem 1.4rem;
  font-family: var(--mono);
  font-size: 0.8125rem;
  color: var(--muted);
}

/* email sits on its own line; the links share the line below it */
.contact .email { flex: 0 0 100%; }

.contact a {
  color: var(--muted);
  border-bottom-color: var(--rule);
}

.contact a:hover { color: var(--accent-hover); }

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

section { margin-top: 3.25rem; }

h2 {
  font-family: var(--mono);
  font-size: 0.75rem;
  font-weight: 500;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--faint);
  margin: 0 0 1.1rem;
  padding-bottom: 0.55rem;
  border-bottom: 1px solid var(--rule);
}

p { margin: 0 0 1rem; }
p:last-child { margin-bottom: 0; }

/* research focus items */

.focus { margin: 0; padding: 0; list-style: none; }

.focus li { margin: 0 0 1.15rem; }
.focus li:last-child { margin-bottom: 0; }

.focus .lede {
  font-weight: 700;
}

/* selected work */

.work { margin: 0; padding: 0; list-style: none; }

.work li {
  margin: 0 0 1.35rem;
}
.work li:last-child { margin-bottom: 0; }

.tag {
  display: block;
  font-family: var(--mono);
  font-size: 0.75rem;
  letter-spacing: 0.04em;
  color: var(--faint);
  margin-bottom: 0.15rem;
}

.work .title { font-weight: 700; }

.work .note {
  display: block;
  color: var(--muted);
  font-size: 1rem;
}

/* ---------- footer ---------- */

footer {
  margin-top: 4rem;
  padding-top: 1.25rem;
  border-top: 1px solid var(--rule);
  font-family: var(--mono);
  font-size: 0.75rem;
  color: var(--faint);
  display: flex;
  justify-content: space-between;
  gap: 1rem;
  flex-wrap: wrap;
}

footer a { color: var(--faint); border-bottom-color: var(--rule); }
footer a:hover { color: var(--accent-hover); }

/* ---------- background page ---------- */

.crumb {
  font-family: var(--mono);
  font-size: 0.8125rem;
  color: var(--muted);
  margin-bottom: 2.5rem;
}

.crumb a { color: var(--muted); border-bottom-color: var(--rule); }
.crumb a:hover { color: var(--accent-hover); }

.entry {
  display: grid;
  grid-template-columns: 8.25rem 1fr;
  gap: 0.2rem 1.25rem;
  margin-bottom: 1.1rem;
}
.entry:last-child { margin-bottom: 0; }

.entry .when {
  font-family: var(--mono);
  font-size: 0.75rem;
  color: var(--faint);
  padding-top: 0.3rem;
  white-space: nowrap;
}

.entry .what { min-width: 0; }
.entry .what .org { font-weight: 700; }
.entry .what .detail { color: var(--muted); font-size: 1rem; }

/* publications */

.pubnote { color: var(--muted); font-size: 0.9375rem; }

.pub {
  display: grid;
  grid-template-columns: 8.25rem 1fr;
  gap: 0.2rem 1.25rem;
  margin-bottom: 1.3rem;
}

.pub .venue {
  font-family: var(--mono);
  font-size: 0.75rem;
  line-height: 1.5;
  color: var(--faint);
  padding-top: 0.3rem;
}

.pub .body { min-width: 0; }
.pub .body .title { font-weight: 700; }
.pub .body .authors {
  display: block;
  color: var(--muted);
  font-size: 0.9375rem;
}
.pub .body .authors .me { color: var(--ink); }
.pub .body .links {
  display: block;
  font-family: var(--mono);
  font-size: 0.75rem;
  margin-top: 0.2rem;
  color: var(--faint);
}

/* simple lists on background page */

.plain { margin: 0; padding-left: 1.1rem; }
.plain li { margin-bottom: 0.5rem; }
.plain li:last-child { margin-bottom: 0; }
.plain .sub { color: var(--muted); font-size: 0.9375rem; }

/* talks */

.talk { margin-bottom: 1rem; }
.talk:last-child { margin-bottom: 0; }
.talk .title { font-weight: 700; }
.talk .where { color: var(--muted); font-size: 0.9375rem; }

/* ---------- load animation ---------- */

@media (prefers-reduced-motion: no-preference) {
  .rise {
    opacity: 0;
    transform: translateY(9px);
    animation: rise 600ms cubic-bezier(0.2, 0.6, 0.2, 1) forwards;
  }
  .rise:nth-child(1) { animation-delay: 40ms; }
  .rise:nth-child(2) { animation-delay: 110ms; }
  .rise:nth-child(3) { animation-delay: 180ms; }
  .rise:nth-child(4) { animation-delay: 250ms; }
  .rise:nth-child(5) { animation-delay: 320ms; }
  .rise:nth-child(6) { animation-delay: 390ms; }
  .rise:nth-child(7) { animation-delay: 460ms; }

  @keyframes rise {
    to { opacity: 1; transform: none; }
  }
}

/* ---------- small screens ---------- */

@media (max-width: 620px) {
  .page { padding-top: 2.75rem; }

  .masthead { flex-direction: column-reverse; }
  .masthead .portrait { width: 5.5rem; height: 5.5rem; }
  .masthead h1 { font-size: 1.9rem; }
  .masthead .hanzi { display: block; margin: 0.35rem 0 0; font-size: 1.05rem; }

  .entry, .pub { grid-template-columns: 1fr; gap: 0.1rem; }
  .entry .when, .pub .venue { padding-top: 0; }
}