/* ============================================================
   Wenjie HUANG — Personal Academic Homepage
   Pure static site for GitHub Pages. No build step required.
   ============================================================ */

:root {
  --bg: #ffffff;
  --surface: #f6f8f9;
  --surface-2: #eef1f3;
  --text: #1c2024;
  --muted: #5b6570;
  --border: #e3e7eb;
  --accent: #00563a;        /* HKU green */
  --accent-soft: #e9f1ed;
  --link: #0b5fa5;
  --shadow: 0 1px 2px rgba(16, 24, 40, .04), 0 4px 16px rgba(16, 24, 40, .05);
  --serif: Georgia, "Times New Roman", "Songti SC", "Noto Serif", serif;
  --sans: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue",
          "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", Arial, sans-serif;
  --radius: 10px;
  --maxw: 940px;
}

[data-theme="dark"] {
  --bg: #0e1113;
  --surface: #161a1d;
  --surface-2: #1d2226;
  --text: #e7ebef;
  --muted: #98a2ad;
  --border: #2a3034;
  --accent: #63c39b;
  --accent-soft: #16261f;
  --link: #79b8ea;
  --shadow: 0 1px 2px rgba(0, 0, 0, .3), 0 4px 16px rgba(0, 0, 0, .25);
}

* { box-sizing: border-box; }

html { scroll-behavior: smooth; }

body {
  margin: 0;
  background: var(--bg);
  color: var(--text);
  font-family: var(--sans);
  font-size: 16px;
  line-height: 1.68;
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
}

a { color: var(--link); text-decoration: none; }
a:hover { text-decoration: underline; }

.wrap { max-width: var(--maxw); margin: 0 auto; padding: 0 24px; }

/* ---------- Skip link ---------- */
.skip {
  position: absolute; left: -9999px; top: 0;
  background: var(--accent); color: #fff; padding: 8px 14px; z-index: 100;
}
.skip:focus { left: 8px; top: 8px; }

/* ---------- Masthead ---------- */
.masthead {
  border-bottom: 1px solid var(--border);
  background: var(--surface);
}
.masthead-inner {
  display: flex; gap: 26px; align-items: flex-start;
  padding: 40px 0 32px;
}
/* circular avatar, fixed size (1/3 of the previous stretched diameter) */
.avatar-slot { flex: 0 0 250px; }
.avatar {
  width: 250px; height: 250px; border-radius: 50%;
  object-fit: cover; object-position: center 22%;
  background: var(--surface-2);
  border: 1px solid var(--border); display: block;
}
.avatar[hidden] { display: none; }
.avatar-placeholder {
  width: 250px; height: 250px; border-radius: 50%;
  display: flex; align-items: center; justify-content: center;
  background: var(--accent-soft); color: var(--accent);
  font-family: var(--serif); font-size: 64px; letter-spacing: 1px;
  border: 1px solid var(--border); user-select: none;
}
.masthead-text { flex: 1 1 auto; min-width: 0; }
.masthead h1 {
  font-family: var(--serif);
  font-size: 34px; line-height: 1.2; margin: 0 0 4px;
  font-weight: 600; letter-spacing: .2px;
}
.masthead .zh-name { color: var(--muted); font-size: 15px; margin: 0 0 10px; }
.masthead .role { font-size: 16.5px; margin: 0; font-weight: 600; }
.masthead .affil { margin: 0; color: var(--muted); font-size: 16.5px; }
.masthead .affil strong { color: var(--text); font-weight: 600; }

.contact {
  list-style: none; margin: 16px 0 0; padding: 0;
  display: flex; flex-wrap: wrap; gap: 6px 22px; font-size: 14.5px;
}
.contact li { display: flex; align-items: center; gap: 7px; color: var(--muted); }
.contact a { color: var(--link); }
.contact svg { width: 15px; height: 15px; flex: 0 0 15px; fill: var(--muted); }

.badges { display: flex; flex-wrap: wrap; gap: 8px; margin-top: 16px; }
.badge {
  display: inline-flex; align-items: center; gap: 6px;
  font-size: 13.5px; padding: 5px 12px; border-radius: 999px;
  border: 1px solid var(--border); background: var(--bg); color: var(--text);
}
.badge:hover { border-color: var(--accent); text-decoration: none; }
.badge svg { width: 14px; height: 14px; fill: var(--accent); }

/* ---------- Nav ---------- */
.nav {
  position: sticky; top: 0; z-index: 50;
  background: var(--bg); border-bottom: 1px solid var(--border);
}
.nav-inner {
  display: flex; align-items: center; gap: 4px;
  max-width: var(--maxw); margin: 0 auto; padding: 0 24px;
  overflow-x: auto; scrollbar-width: none;
}
.nav-inner::-webkit-scrollbar { display: none; }
.nav a {
  padding: 13px 14px; font-size: 15px; color: var(--muted);
  border-bottom: 2px solid transparent; white-space: nowrap;
}
.nav a:hover { color: var(--text); text-decoration: none; }
.nav a.active { color: var(--accent); border-bottom-color: var(--accent); font-weight: 600; }
.nav .spacer { flex: 1 1 auto; }
.theme-toggle {
  border: 1px solid var(--border); background: var(--surface);
  color: var(--muted); border-radius: 999px; cursor: pointer;
  width: 34px; height: 34px; display: inline-flex; align-items: center; justify-content: center;
  flex: 0 0 34px; margin-left: 6px;
}
.theme-toggle:hover { color: var(--text); border-color: var(--accent); }
.theme-toggle svg { width: 17px; height: 17px; fill: currentColor; }

/* ---------- Main ---------- */
main { padding: 34px 0 60px; min-height: 40vh; }

h2 {
  font-family: var(--serif); font-size: 24px; font-weight: 600;
  margin: 38px 0 14px; padding-bottom: 8px;
  border-bottom: 1px solid var(--border);
}
h2:first-child { margin-top: 0; }
h3 {
  font-size: 18px; margin: 28px 0 10px; font-weight: 650;
  color: var(--accent);
}
h4 { font-size: 15.5px; margin: 20px 0 6px; color: var(--muted); font-weight: 650; }

p { margin: 0 0 14px; }

.lede { font-size: 17px; color: var(--text); }

/* Callout */
.callout {
  background: var(--accent-soft); border-left: 3px solid var(--accent);
  padding: 16px 20px; border-radius: 0 var(--radius) var(--radius) 0;
  margin: 0 0 24px;
}
.callout p:last-child { margin-bottom: 0; }

/* ---------- Publication list ---------- */
.pub-tools {
  display: flex; flex-wrap: wrap; gap: 10px; align-items: center;
  margin: 0 0 18px;
}
.pub-search {
  flex: 1 1 220px; min-width: 180px;
  padding: 9px 13px; font-size: 14.5px; font-family: inherit;
  border: 1px solid var(--border); border-radius: 8px;
  background: var(--bg); color: var(--text);
}
.pub-search:focus { outline: 2px solid var(--accent-soft); border-color: var(--accent); }
.filters { display: flex; flex-wrap: wrap; gap: 8px; }
.chip {
  font-size: 13.5px; padding: 6px 13px; border-radius: 999px; cursor: pointer;
  border: 1px solid var(--border); background: var(--surface); color: var(--muted);
  font-family: inherit;
}
.chip:hover { color: var(--text); }
.chip[aria-pressed="true"] {
  background: var(--accent); border-color: var(--accent); color: #fff; font-weight: 600;
}

ol.pubs { list-style: none; counter-reset: p; margin: 0 0 10px; padding: 0; }
ol.pubs > li {
  counter-increment: p; position: relative;
  padding: 12px 0 12px 34px; border-bottom: 1px solid var(--border);
}
ol.pubs > li:last-child { border-bottom: 0; }
ol.pubs > li::before {
  content: "[" counter(p) "]"; position: absolute; left: 0; top: 12px;
  font-size: 13px; color: var(--muted); font-variant-numeric: tabular-nums;
}
/* when JS filtering is active, numbering is recomputed for visible entries */
html.js ol.pubs > li::before { content: "[" var(--n) "]"; }
.pub-title { font-weight: 600; }
.pub-authors { color: var(--muted); font-size: 14.5px; }
.pub-venue { font-size: 14.5px; }
.pub-venue em {
  font-style: italic; font-weight: 700;
  color: #0d8be0;                      /* azure */
}
[data-theme="dark"] .pub-venue em { color: #74bdf5; }
.pub-meta { font-size: 13.5px; color: var(--muted); margin-top: 3px; }
.pub-links { display: inline-flex; gap: 10px; margin-left: 6px; font-size: 13px; }
.tag {
  display: inline-block; font-size: 12px; padding: 1px 8px; border-radius: 5px;
  background: var(--surface-2); color: var(--muted); margin-left: 6px; vertical-align: 1px;
}
.tag.award { background: #fdf0d5; color: #8a5a00; }
[data-theme="dark"] .tag.award { background: #33280f; color: #e8c17a; }
.tag.status { background: var(--accent-soft); color: var(--accent); }
a.pub-title { color: inherit; text-decoration: none; border-bottom: 1px dotted var(--border); }
a.pub-title:hover { color: var(--accent); border-bottom-color: var(--accent); }
a.tag { text-decoration: none; }
a.tag:hover { background: var(--accent-soft); color: var(--accent); }

/* ---------- People / grants / talks lists ---------- */
ul.plain { list-style: none; margin: 0 0 12px; padding: 0; }
ul.plain > li {
  padding: 10px 0; border-bottom: 1px solid var(--border);
}
ul.plain > li:last-child { border-bottom: 0; }
.who { font-weight: 600; }
.when, .where { color: var(--muted); font-size: 14.5px; }
.note { color: var(--muted); font-size: 14.5px; display: block; }

ul.ticks { margin: 0 0 12px; padding-left: 22px; }
ul.ticks li { margin-bottom: 6px; }
.service-line { margin: 0 0 14px; font-size: 15px; line-height: 1.75; }

.grant-role {
  display: inline-block; font-size: 12px; font-weight: 700; letter-spacing: .3px;
  color: var(--accent); background: var(--accent-soft);
  padding: 1px 7px; border-radius: 5px; margin-right: 7px; vertical-align: 1px;
}

/* ---------- Course cards (Teaching) ---------- */
.course-card {
  border: 1px solid var(--border); border-radius: var(--radius);
  padding: 18px 20px; margin: 0 0 16px; background: var(--surface);
}
.course-code {
  font-size: 13.5px; font-weight: 700; letter-spacing: .4px; color: var(--accent);
}
.course-title {
  font-family: var(--serif); font-size: 19px; font-weight: 600; margin: 2px 0 6px;
}
.course-meta { font-size: 14.5px; color: var(--muted); margin: 0 0 10px; }
.course-card p:last-child { margin-bottom: 0; }

/* Timeline (Experience) */
.timeline { margin: 0 0 12px; padding: 0; list-style: none; }
.timeline > li {
  position: relative; padding: 0 0 22px 22px; border-left: 2px solid var(--border);
}
.timeline > li:last-child { border-left-color: transparent; padding-bottom: 0; }
.timeline > li::before {
  content: ""; position: absolute; left: -6px; top: 9px;
  width: 10px; height: 10px; border-radius: 50%;
  background: var(--bg); border: 2px solid var(--accent);
}
.tl-title { font-weight: 650; }
.tl-org { color: var(--text); }
.tl-period { color: var(--muted); font-size: 14px; }
.tl-desc { color: var(--muted); font-size: 14.5px; margin: 4px 0 0; }

/* ---------- Footer ---------- */
footer {
  border-top: 1px solid var(--border); background: var(--surface);
  padding: 26px 0; font-size: 14px; color: var(--muted);
}
footer .wrap { display: flex; flex-wrap: wrap; gap: 10px 24px; justify-content: space-between; }
footer a { color: var(--link); }

/* ---------- Responsive ---------- */
@media (max-width: 720px) {
  .masthead-inner { flex-direction: column; align-items: center; text-align: center; padding: 28px 0 24px; }
  /* stacked layout: same 84px circle, centred */
  .avatar-slot { flex: 0 0 auto; align-self: center; }
  .masthead-text { width: 100%; }
  .masthead h1 { font-size: 28px; }
  .contact { justify-content: center; }
  .badges { justify-content: center; }
  main { padding: 26px 0 44px; }
  ol.pubs > li { padding-left: 0; }
  ol.pubs > li::before { position: static; margin-right: 6px; }
}

@media print {
  .nav, .theme-toggle, .pub-tools, footer { display: none !important; }
  body { font-size: 12pt; }
  a { color: #000; text-decoration: none; }
  .pub-venue em { color: #000; }
  .pub-venue em { color: #000; }
}