/* ============================================================
   Yihuan Huang — Academic homepage
   Design: "Light Pixel" — bright retro-game console
   Pixel borders, hard shadows, Press Start 2P + VT323
   ============================================================ */

/* ---------- Tokens ---------- */
:root {
  color-scheme: light;

  /* Bright light palette */
  --paper:        #FFF6E9;   /* warm cream ground */
  --paper-deep:   #FFF1DA;   /* deeper cream for fills */
  --card:         #FFFFFF;   /* card surface */
  --ink:          #2B2B3A;   /* near-black ink */
  --ink-soft:     #55556A;   /* secondary text */
  --ink-faint:    #7A7A90;   /* captions, meta */

  /* Candy accents */
  --rust:         #FF5C8A;   /* bubblegum pink — name, emphasis */
  --rust-soft:    #FF7BA0;   /* hover */
  --indigo:       #4FC3F7;   /* sky blue — links, data */
  --indigo-soft:  #7DD3FA;   /* hover */
  --highlight:    #FFD23F;   /* lemon yellow highlighter */
  --highlight-ink:#4A3B1E;   /* text over highlight */

  /* Extra candy colors */
  --orange:       #FF9F45;   /* sunny orange */
  --green:        #4CC38A;   /* mint green */
  --purple:       #A78BFA;   /* soft purple */

  /* Hairlines */
  --rule:         #D8CFB8;   /* light borders */
  --rule-strong:  #B9AE97;

  /* Type */
  --font-display: "Press Start 2P", "VT323", monospace;
  --font-body:    "VT323", "Press Start 2P", "PingFang SC", "Microsoft YaHei", monospace;
  --font-mono:    "VT323", "Press Start 2P", ui-monospace, Menlo, monospace;

  /* Radii (pixel: no rounding) & pixel hard shadows */
  --r-sm: 0;
  --r-md: 0;
  --shadow-card: 3px 3px 0 rgba(43,43,58,.14);
  --shadow-lift: 4px 4px 0 var(--blue, #4FC3F7);

  /* Motion */
  --ease: steps(2, end);
  --t-fast: 100ms;
  --t-med: 160ms;
}

/* ---------- Reset / base ---------- */
*, *::before, *::after { box-sizing: border-box; }
html { scroll-behavior: smooth; scroll-padding-top: 84px; }
body {
  margin: 0;
  background: var(--paper);
  color: var(--ink);
  font-family: var(--font-body);
  font-size: 20px;
  line-height: 1.5;
  background-image:
    radial-gradient(circle at 15% 8%, rgba(255,210,63,.14), transparent 38%),
    radial-gradient(circle at 85% 92%, rgba(79,195,247,.12), transparent 42%),
    repeating-linear-gradient(0deg, transparent 0 2px, rgba(120,100,60,.03) 2px 3px);
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
}
img { max-width: 100%; display: block; }
a { color: var(--indigo); text-decoration-color: color-mix(in srgb, var(--indigo) 40%, transparent); text-underline-offset: 3px; transition: color var(--t-fast) var(--ease); }
a:hover { color: var(--rust); }

::selection { background: var(--highlight); color: var(--highlight-ink); }

:focus-visible { outline: 3px solid var(--indigo); outline-offset: 3px; }

.container { width: min(1120px, 92vw); margin: 0 auto; }

/* Faint scanline overlay */
body::before {
  content: "";
  position: fixed;
  inset: 0;
  pointer-events: none;
  z-index: 0;
  opacity: .5;
  background-image:
    repeating-linear-gradient(0deg, transparent 0 2px, rgba(0,0,0,.025) 2px 3px);
}
main, header, footer { position: relative; z-index: 1; }

/* ---------- Type scale ---------- */
h1, h2, h3, h4 { font-family: var(--font-display); line-height: 1.3; margin: 0; }
.display {
  font-family: var(--font-display);
  font-size: clamp(1.3rem, 3.2vw, 2rem);
  font-weight: 400;
  letter-spacing: .01em;
  line-height: 1.4;
}
.eyebrow {
  font-family: var(--font-display);
  font-size: .7rem;
  letter-spacing: .12em;
  text-transform: uppercase;
  color: var(--green);
  font-weight: 400;
}
.section-title {
  font-family: var(--font-display);
  font-size: clamp(1rem, 2.2vw, 1.35rem);
  font-weight: 400;
  display: flex;
  align-items: baseline;
  gap: .6rem;
  margin-bottom: 1.4rem;
  text-shadow: 2px 2px 0 var(--highlight);
}
.section-title .num { font-family: var(--font-display); font-size: .85rem; color: var(--rust); font-weight: 400; letter-spacing: .05em; }
.section-title .cn { font-family: var(--font-body); font-size: .55em; color: var(--ink-faint); font-weight: 400; text-shadow: none; }

.mono { font-family: var(--font-mono); font-size: .85rem; }
.meta { font-family: var(--font-mono); font-size: .8rem; color: var(--ink-faint); letter-spacing: .03em; }

/* ---------- Nav ---------- */
.site-nav {
  position: sticky;
  top: 0;
  z-index: 50;
  background: color-mix(in srgb, var(--paper) 90%, transparent);
  backdrop-filter: blur(8px);
  border-bottom: 3px solid var(--highlight);
}
.nav-inner { display: flex; align-items: center; justify-content: space-between; height: 52px; }
.nav-brand { font-family: var(--font-display); font-weight: 400; font-size: .95rem; letter-spacing: .01em; color: var(--rust); text-decoration: none; text-shadow: 2px 2px 0 var(--highlight); }
.nav-brand .dot { color: var(--orange); }
.nav-links { display: flex; gap: 1.4rem; align-items: center; }
.nav-links a { font-family: var(--font-display); font-size: .68rem; color: var(--ink-soft); text-decoration: none; font-weight: 400; }
.nav-links a:hover { color: var(--blue, var(--indigo)); }
.nav-links .is-active { color: var(--ink); box-shadow: inset 0 -3px 0 var(--rust); padding-bottom: 3px; }
.nav-toggle { display: none; background: none; border: 3px solid var(--ink); padding: .2rem .5rem; cursor: pointer; font-size: 1rem; color: var(--ink); box-shadow: 2px 2px 0 rgba(0,0,0,.2); }
@media (max-width: 720px) {
  .nav-toggle { display: block; }
  .nav-links {
    position: absolute; top: 52px; left: 0; right: 0;
    flex-direction: column; align-items: stretch; gap: 0;
    background: var(--card); border-bottom: 3px solid var(--ink);
    padding: .4rem 6%; display: none;
    box-shadow: var(--shadow-card);
  }
  .nav-links.open { display: flex; }
  .nav-links a { padding: .6rem 0; border-bottom: 2px solid var(--rule); }
  .nav-links a:last-child { border-bottom: none; }
}

/* ---------- Hero ---------- */
.hero { padding: clamp(2.4rem, 6vw, 4rem) 0 clamp(2rem, 4vw, 3rem); }
.hero-grid { display: grid; grid-template-columns: 240px 1fr; gap: clamp(1.4rem, 3vw, 2.6rem); align-items: stretch; }
@media (max-width: 820px) { .hero-grid { grid-template-columns: 1fr; } }

/* Portrait card — like a game character panel */
.portrait-card {
  position: sticky; top: 68px;
  background: var(--card);
  border: 3px solid var(--ink);
  box-shadow: inset 0 0 0 3px var(--card), inset 0 0 0 5px var(--rule), 6px 6px 0 rgba(43,43,58,.14);
  padding: 1.2rem 1.2rem 1rem;
}
.portrait-card .file-tab {
  font-family: var(--font-display); font-size: .55rem; letter-spacing: .1em;
  text-transform: uppercase; color: var(--green);
  display: block; margin-bottom: .8rem; border-bottom: 2px dashed var(--rule-strong); padding-bottom: .4rem;
}
.avatar {
  width: 100%; aspect-ratio: 1; object-fit: cover;
  border: 3px solid var(--indigo); image-rendering: pixelated;
}
.portrait-card .name { font-family: var(--font-display); font-size: 1.05rem; font-weight: 400; margin-top: .8rem; line-height: 1.3; color: var(--rust); text-shadow: 2px 2px 0 var(--highlight); }
.portrait-card .name-zh { font-family: var(--font-body); font-size: 1rem; color: var(--ink-soft); }
.portrait-card .role { font-size: .8rem; color: var(--ink-soft); margin: .4rem 0 .8rem; }
.id-links { display: grid; gap: .35rem; }
.id-links a {
  display: flex; align-items: center; gap: .55rem;
  font-size: .8rem; color: var(--ink-soft); text-decoration: none;
  padding: .25rem .2rem; border: 2px solid var(--rule);
}
.id-links a:hover { color: var(--orange); border-color: var(--orange); background: var(--paper); }
.id-links svg { width: 14px; height: 14px; flex: none; color: var(--indigo); }
.id-links a:hover svg { color: var(--orange); }
.hr-rule { border: 0; border-top: 2px dashed var(--rule-strong); margin: .9rem 0 .6rem; }
.stat-row { display: grid; grid-template-columns: 1fr 1fr; gap: .5rem; }
.stat { text-align: center; padding: .4rem 0; border: 2px solid var(--rule); }
.stat .n { font-family: var(--font-display); font-size: 1.1rem; font-weight: 400; color: var(--orange); display: block; line-height: 1.1; text-shadow: 0 0 8px rgba(255,159,69,.3); }
.stat .l { font-family: var(--font-display); font-size: .45rem; letter-spacing: .1em; text-transform: uppercase; color: var(--ink-faint); }

/* Hero statement */
.hero-statement { display: flex; flex-direction: column; min-height: 100%; }
.hero-statement .eyebrow { margin-bottom: .8rem; display: block; }
.hero-statement .lede { font-size: 1.05rem; color: var(--ink-soft); max-width: 60ch; margin: 1rem 0 1.2rem; }
.stamp-line { display: inline-flex; align-items: center; gap: .5rem; font-family: var(--font-display); font-size: .65rem; color: var(--orange); border: 2px dashed var(--orange); padding: .35rem .7rem; transform: rotate(-1.2deg); align-self: flex-start; }
.stamp-line::before { content: "▶"; font-size: .6rem; }
.hero-research { margin-top: auto; padding-top: 1.4rem; }
.chip {
  font-family: var(--font-display); font-size: .6rem; letter-spacing: .02em;
  color: var(--indigo); background: color-mix(in srgb, var(--indigo) 8%, transparent);
  border: 2px solid color-mix(in srgb, var(--indigo) 40%, transparent);
  padding: .3rem .7rem; text-decoration: none;
  transition: background var(--t-fast) var(--ease), color var(--t-fast) var(--ease);
}
.chip:hover { background: var(--indigo); color: var(--card); }

/* ---------- Research directions (compact pixel cards) ---------- */
.research-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: .8rem;
  align-items: stretch;
}
.research-line {
  display: flex;
  flex-direction: column;
  border: 3px solid var(--rule);
  border-top: 4px solid var(--indigo);
  background: var(--card);
  padding: .9rem .9rem .8rem;
  box-shadow: var(--shadow-card);
  transition: transform var(--t-med) var(--ease), box-shadow var(--t-med) var(--ease);
}
.research-line:hover { transform: translate(-2px,-2px); box-shadow: 4px 4px 0 var(--indigo); }
.research-line .rl-top { display: flex; align-items: baseline; gap: .5rem; }
.research-line .rl-icon { width: 20px; height: 20px; flex: none; color: var(--orange); }
.research-line h3 { font-family: var(--font-display); font-size: .68rem; font-weight: 400; line-height: 1.4; }
.research-line .rl-cn { font-family: var(--font-body); font-size: .72rem; color: var(--ink-soft); font-weight: 400; }
.research-line .rl-count { font-family: var(--font-display); font-size: .5rem; color: var(--green); margin-top: .4rem; }
.research-line .rl-blurb { color: var(--ink-soft); font-size: .82rem; line-height: 1.45; margin: .4rem 0 0; flex: 1; }
.research-line .rl-blurb[lang="zh"] { font-size: .78rem; }
.research-line .rl-links { margin-top: .5rem; }
.research-line .rl-links a { font-family: var(--font-display); font-size: .55rem; color: var(--indigo); }
.research-line .rl-links svg { width: 10px; height: 10px; vertical-align: -2px; }
@media (max-width: 980px) {
  .research-grid { grid-template-columns: repeat(2, 1fr); }
}
@media (max-width: 560px) {
  .research-grid { grid-template-columns: 1fr; }
}

/* ---------- Timeline ---------- */
.timeline { position: relative; margin: 1.2rem 0 1rem; padding-left: 24px; }
.timeline::before {
  content: ""; position: absolute; left: 6px; top: 6px; bottom: 6px;
  width: 3px; background: var(--rule-strong);
}
.tl-item { position: relative; padding: 0 0 1.1rem 1rem; }
.tl-item:last-child { padding-bottom: 0; }
.tl-item::before {
  content: ""; position: absolute; left: -24px; top: .4rem;
  width: 13px; height: 13px;
  background: var(--card); border: 3px solid var(--rust);
}
.tl-item.is-now::before { background: var(--rust); }
.tl-item .tl-date { font-family: var(--font-display); font-size: .6rem; color: var(--rust); font-weight: 400; letter-spacing: .03em; }
.tl-item .tl-body { color: var(--ink-soft); font-size: 1rem; margin-top: .2rem; }
.tl-item .tl-body strong { color: var(--ink); }
.tl-item .tl-badge { display: inline-block; font-family: var(--font-display); font-size: .5rem; letter-spacing: .06em; text-transform: uppercase; color: var(--indigo); border: 2px solid color-mix(in srgb, var(--indigo) 45%, transparent); padding: .05rem .4rem; margin-right: .4rem; vertical-align: 1px; }

/* ---------- Publications ---------- */
.pub-group { margin-bottom: 2.2rem; }
.pub-group-head { display: flex; align-items: baseline; gap: .7rem; margin-bottom: .9rem; }
.pub-group-head h3 { font-family: var(--font-display); font-size: .95rem; font-weight: 400; }
.pub-group-head .pub-count { font-family: var(--font-display); font-size: .55rem; color: var(--green); }
.pub-card {
  position: relative;
  background: var(--card);
  border: 3px solid var(--rule);
  padding: .9rem 1.1rem .9rem;
  margin: 0 0 .7rem;
  box-shadow: var(--shadow-card);
  transition: box-shadow var(--t-med) var(--ease), transform var(--t-med) var(--ease);
}
.pub-card:hover { box-shadow: 4px 4px 0 var(--indigo); transform: translate(-2px,-2px); }

/* Evidence index tag — pixel block */
.pub-card .evidence-tag {
  display: inline-block;
  vertical-align: 3px;
  font-family: var(--font-display); font-size: .5rem; letter-spacing: .08em;
  color: var(--card); background: var(--orange);
  padding: .16rem .45rem;
  margin-right: .55rem;
  box-shadow: 2px 2px 0 var(--ink);
}

.pub-card .pub-title-row { display: flex; align-items: flex-start; gap: .4rem; }
.pub-card .pub-title { font-family: var(--font-display); font-size: .78rem; font-weight: 400; line-height: 1.5; flex: 1; min-width: 0; }
.pub-card .pub-title a { color: var(--ink); text-decoration: none; }
.pub-card .pub-title a:hover { color: var(--indigo); text-decoration: underline; text-underline-offset: 3px; }
.pub-card .pub-authors { font-size: .9rem; color: var(--ink-soft); margin-top: .3rem; }
.pub-card .pub-authors .me { color: var(--rust); font-weight: 700; text-decoration: underline; text-decoration-color: var(--rust); text-decoration-thickness: 2px; text-underline-offset: 2px; }
.pub-card .pub-meta { margin-top: .5rem; display: flex; flex-wrap: wrap; gap: .5rem .8rem; align-items: center; }
.pub-venue { font-family: var(--font-display); font-size: .55rem; color: var(--indigo); background: var(--paper-deep); border: 2px solid var(--rule); padding: .1rem .45rem; }
.pub-type { font-family: var(--font-display); font-size: .5rem; letter-spacing: .08em; text-transform: uppercase; color: var(--indigo); }
.pub-year { font-family: var(--font-display); font-size: .55rem; color: var(--ink-faint); }
.pub-tags { margin-top: .5rem; display: flex; flex-wrap: wrap; gap: .35rem; }
.pub-tag { font-family: var(--font-display); font-size: .48rem; color: var(--ink-soft); border: 2px solid var(--rule); padding: .05rem .45rem; background: var(--paper); }
.pub-highlight {
  margin-top: .55rem;
  background: linear-gradient(transparent 15%, var(--highlight) 15% 85%, transparent 85%);
  display: inline; box-decoration-break: clone; -webkit-box-decoration-break: clone;
  padding: .05em .3em; font-size: .95rem; color: var(--highlight-ink);
}
.role-badge { font-family: var(--font-display); font-size: .5rem; letter-spacing: .06em; text-transform: uppercase; color: var(--rust); border: 2px solid var(--rust); padding: .05rem .45rem; }
.pres-badge { font-family: var(--font-display); font-size: .5rem; letter-spacing: .06em; text-transform: uppercase; padding: .05rem .45rem; }
.pres-spotlight { color: var(--orange); border: 2px solid var(--orange); background: color-mix(in srgb, var(--highlight) 40%, transparent); }
.pres-poster { color: var(--indigo); border: 2px solid color-mix(in srgb, var(--indigo) 45%, transparent); }

/* ---------- News / lists ---------- */
.list-card { background: var(--card); border: 3px solid var(--rule); padding: 1rem 1.2rem; box-shadow: var(--shadow-card); }
.list-item { display: grid; grid-template-columns: 118px 1fr; gap: 1rem; padding: .5rem 0; border-bottom: 2px dashed var(--rule); }
.list-item:last-child { border-bottom: 0; }
.list-item .when { font-family: var(--font-display); font-size: .6rem; color: var(--green); font-weight: 400; padding-top: .15rem; }
.list-item .what { font-size: .95rem; color: var(--ink-soft); }
.list-item .what strong { color: var(--ink); font-weight: 700; }
.list-item .what a { color: var(--indigo); }

/* Two-col for news-ish */
.grid-2 { display: grid; grid-template-columns: 1fr 1fr; gap: 1.2rem; }
@media (max-width: 820px) { .grid-2 { grid-template-columns: 1fr; } }

/* ---------- Scroll cards (News / Honors / Experience) ---------- */
/* Pinwheel layout (rotated 90°): wide News on the left, stacked Honors + Experience on the right */
.news-pinwheel {
  display: grid;
  grid-template-columns: 1.6fr 1fr;
  gap: 1.2rem;
  align-items: stretch;
}
.news-main { height: 400px; }
.news-stack {
  display: grid;
  grid-template-rows: 1fr 1fr;
  gap: 1.2rem;
  height: 400px;
}
.news-stack .scroll-card { height: 100%; }
.scroll-card {
  display: flex;
  flex-direction: column;
  background: var(--card);
  border: 3px solid var(--rule);
  border-top: 4px solid var(--indigo);
  box-shadow: var(--shadow-card);
  overflow: hidden;
  min-height: 0;
}
.scroll-card-title {
  font-family: var(--font-display);
  font-size: .7rem;
  font-weight: 400;
  padding: .8rem 1.1rem .6rem;
  border-bottom: 2px solid var(--rule);
  color: var(--rust);
  flex: none;
}
.scroll-card-body {
  padding: .2rem 1.1rem .9rem;
  overflow-y: auto;
  flex: 1;
  min-height: 0;
  scrollbar-width: thin;
  scrollbar-color: var(--rule-strong) transparent;
}
.scroll-card-body::-webkit-scrollbar { width: 8px; }
.scroll-card-body::-webkit-scrollbar-thumb { background: var(--orange); }
.scroll-card-body::-webkit-scrollbar-track { background: transparent; }
.scroll-card-body .list-item { grid-template-columns: 82px 1fr; }
@media (max-width: 980px) {
  .news-pinwheel { grid-template-columns: 1fr; }
  .news-stack { grid-template-rows: none; }
}

/* ---------- Sections ---------- */
section.block { padding: 2.4rem 0 1rem; scroll-margin-top: 68px; }

/* ---------- Blog post ---------- */
.post-page { padding: 2.6rem 0 2rem; }
.post-header { margin-bottom: 2rem; }
.post-body { font-size: 1rem; color: var(--ink-soft); }
.post-body h1, .post-body h2, .post-body h3 { color: var(--ink); margin: 1.6em 0 .5em; }
.post-body h2 { font-family: var(--font-display); font-size: 1rem; }
.post-body h3 { font-family: var(--font-display); font-size: .8rem; }
.post-body p { margin: 0 0 1.1em; }
.post-body ul, .post-body ol { padding-left: 1.4em; margin: 0 0 1.1em; }
.post-body li { margin-bottom: .4em; }
.post-body a { color: var(--indigo); }
.post-body blockquote { border-left: 3px solid var(--rust); margin: 1.4em 0; padding: .2em 1.2em; background: var(--card); }
.post-body code { font-family: var(--font-mono); font-size: .88em; background: var(--paper-deep); padding: .1em .35em; }
.post-body pre { background: var(--ink); color: var(--card); padding: 1.2em 1.4em; overflow-x: auto; }
.post-body pre code { background: none; padding: 0; color: inherit; }

/* ---------- Footer ---------- */
.site-footer { border-top: 3px solid var(--highlight); margin-top: 3.6rem; padding: 2rem 0 2.4rem; }
.footer-inner { display: flex; justify-content: space-between; align-items: center; gap: 1rem; flex-wrap: wrap; }
.footer-inner .meta { color: var(--ink-faint); }
.footer-inner .heart { color: var(--rust); }

/* Visitor counter */
.visitor-row {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: .7rem;
  margin-top: 1.2rem;
  flex-wrap: wrap;
}
.visitor-row img {
  display: inline-block;
  vertical-align: middle;
  image-rendering: pixelated;
}
.visitor-label {
  font-family: var(--font-display);
  font-size: .6rem;
  color: var(--ink-faint);
  letter-spacing: .03em;
}
.footer-up { font-family: var(--font-display); font-size: .6rem; color: var(--indigo); text-decoration: none; }

/* ---------- Motion ---------- */
.reveal { opacity: 0; transform: translateY(14px); transition: opacity .5s var(--ease), transform .5s var(--ease); }
.reveal.in { opacity: 1; transform: none; }

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  *, *::before, *::after { transition: none !important; animation: none !important; }
  .reveal { opacity: 1; transform: none; }
}

/* ---------- Print ---------- */
@media print {
  body { background: #fff; }
  .site-nav, .footer-up, .reveal { display: none; }
  .hero-grid { grid-template-columns: 1fr; }
  .portrait-card { position: static; }
}