:root{
  --ink:#171321;
  --muted:#665f71;
  --line:#eadff0;
  --bg:#fbf8ff;
  --card:#fffdf8;
  --primary:#6f2c91;
  --secondary:#4b1766;
  --gold:#f2c75c;
  --copper:#b68a1c;
  --accent:#b68a1c;
  --soft:#f5ecfa;
  --shadow:0 14px 34px rgba(80,38,105,.10);
  --radius:22px;
}
*{box-sizing:border-box}
html{scroll-behavior:smooth}
body{margin:0;font-family:Inter,ui-sans-serif,system-ui,-apple-system,BlinkMacSystemFont,"Segoe UI",Arial,sans-serif;color:var(--ink);background:var(--bg);line-height:1.65}
a{color:var(--primary);text-decoration:none}a:hover{text-decoration:underline}
.container{width:min(1120px,92vw);margin:0 auto}.narrow{width:min(860px,92vw);margin:0 auto}
.site-header{position:sticky;top:0;z-index:50;background:rgba(255,255,255,.92);backdrop-filter:blur(14px);border-bottom:1px solid var(--line)}
.nav{display:flex;align-items:center;justify-content:space-between;gap:20px;padding:12px 0}.brand{display:flex;align-items:center;gap:12px;color:var(--ink);font-weight:800;letter-spacing:-.03em}.brand-mark{width:38px;height:38px;border-radius:12px;background:linear-gradient(135deg,var(--primary),var(--secondary) 65%,var(--copper));box-shadow:0 10px 24px rgba(11,79,74,.22)}.brand small{display:block;font-weight:600;color:var(--muted);letter-spacing:0;font-size:12px;margin-top:-2px}
.nav-links{display:flex;align-items:center;gap:18px;font-size:15px}.nav-links a{color:#334155}.nav-links a.active{color:var(--primary);font-weight:800}.menu-button{display:none;border:1px solid var(--line);background:white;border-radius:14px;padding:9px 12px;font-weight:700;color:var(--ink)}
.hero{padding:58px 0 34px;background:radial-gradient(circle at top left,#e9f3ef 0,transparent 34%),radial-gradient(circle at 82% 18%,#f8ecd8 0,transparent 26%)}.hero-grid{display:grid;grid-template-columns:1.05fr .95fr;gap:42px;align-items:center}.eyebrow{display:inline-flex;align-items:center;gap:8px;padding:8px 12px;background:#fff;border:1px solid var(--line);border-radius:999px;color:var(--secondary);font-weight:800;font-size:13px}.hero h1{font-size:clamp(42px,7vw,72px);line-height:1.02;margin:20px 0 18px;letter-spacing:-.06em}.hero p{font-size:19px;color:#475569;margin:0 0 26px}.hero-art img{width:100%;display:block}.actions{display:flex;flex-wrap:wrap;gap:12px}.button{display:inline-flex;align-items:center;justify-content:center;border-radius:16px;padding:12px 18px;font-weight:800;border:1px solid transparent}.button.primary{background:var(--primary);color:#fff;box-shadow:0 14px 26px rgba(11,79,74,.2)}.button.secondary{background:#fff;color:var(--primary);border-color:var(--line)}
.section{padding:42px 0}.section-title{display:flex;align-items:end;justify-content:space-between;gap:20px;margin-bottom:14px}.section-title h2,.page-title h1{font-size:clamp(30px,4vw,46px);line-height:1.1;letter-spacing:-.045em;margin:0}.section-title p,.page-title p{color:var(--muted);max-width:720px;margin:4px 0 0}.page-title{padding:34px 0 16px;background:linear-gradient(180deg,#fff,transparent)}
.grid{display:grid;gap:20px}.grid.three{grid-template-columns:repeat(3,1fr)}.grid.two{grid-template-columns:repeat(2,1fr)}.card{background:var(--card);border:1px solid var(--line);border-radius:var(--radius);padding:22px;box-shadow:var(--shadow)}.card h3{margin:0 0 10px;font-size:21px;letter-spacing:-.025em}.card p{margin:0;color:#475569}.card .icon{width:44px;height:44px;border-radius:15px;background:linear-gradient(135deg,#e9f3ef,#eef7f5);display:grid;place-items:center;margin-bottom:18px;color:var(--primary);font-weight:900}.metric-row{display:grid;grid-template-columns:repeat(4,1fr);gap:16px;margin-top:18px}.metric{background:#fff;border:1px solid var(--line);border-radius:20px;padding:18px}.metric strong{font-size:28px;display:block;color:var(--primary)}.metric span{font-size:13px;color:var(--muted);font-weight:700;text-transform:uppercase;letter-spacing:.05em}
.publication{display:grid;grid-template-columns:auto 1fr;gap:16px;align-items:start}.pub-year{font-weight:900;color:#fff;background:linear-gradient(135deg,var(--primary),var(--secondary));border-radius:16px;padding:10px 12px;min-width:66px;text-align:center}.publication h3{font-size:18px;margin:0 0 6px}.authors{color:#475569;font-size:15px}.journal{color:var(--muted);font-size:15px}.tags{display:flex;gap:8px;flex-wrap:wrap;margin-top:10px}.tag{background:#f1f5f9;color:#334155;border:1px solid var(--line);border-radius:999px;padding:4px 9px;font-size:12px;font-weight:800}.tag.gold{background:#fff7e8;color:#8a5418;border-color:#efd6a4}.people-card{display:grid;grid-template-columns:150px 1fr;gap:22px;align-items:start}.people-card img{width:150px;border-radius:24px;border:1px solid var(--line);background:#fff}.role{font-weight:800;color:var(--secondary);margin-bottom:8px}.meta{color:var(--muted);font-size:14px}.timeline{max-width:860px;margin:0 auto;border-left:3px solid #dbe7e3}.timeline-item{position:relative;margin:0 0 22px 28px;background:#fff;border:1px solid var(--line);border-radius:20px;padding:18px;box-shadow:var(--shadow)}.timeline-item:before{content:"";position:absolute;left:-39px;top:22px;width:16px;height:16px;border-radius:999px;background:var(--copper);border:4px solid #fff;box-shadow:0 0 0 2px #efd6a4}.date{font-weight:900;color:var(--primary);font-size:14px}.footer{margin-top:30px;padding:36px 0;background:#0f172a;color:#cbd5e1}.footer a{color:#fff}.footer-grid{display:grid;grid-template-columns:1.2fr .8fr;gap:24px}.footer h3{color:#fff;margin:0 0 8px}.list-clean{padding:0;margin:0;list-style:none}.list-clean li{padding:7px 0;border-bottom:1px solid rgba(255,255,255,.08)}
.callout{background:linear-gradient(135deg,#3b0a70,#155e75);color:#fff;border-radius:28px;padding:34px;box-shadow:var(--shadow)}.callout p{color:#e2e8f0}.split{display:grid;grid-template-columns:.78fr 1.22fr;gap:28px;align-items:start}.sidebar{position:sticky;top:88px}.soft-box{background:var(--soft);border:1px solid var(--line);border-radius:22px;padding:20px}
@media(max-width:900px){.hero-grid,.grid.three,.grid.two,.metric-row,.footer-grid,.split{grid-template-columns:1fr}.sidebar{position:static}.nav-links{display:none;position:absolute;left:4vw;right:4vw;top:72px;background:#fff;border:1px solid var(--line);border-radius:20px;padding:14px;box-shadow:var(--shadow);flex-direction:column;align-items:flex-start}.nav-links.open{display:flex}.menu-button{display:inline-flex}.people-card{grid-template-columns:1fr}.people-card img{width:132px}.hero{padding-top:46px}}


.air-word strong, .brand strong { font-weight: 900; letter-spacing: 0.02em; }
.note-box { background: #f8fafc; border: 1px solid #e5e7eb; border-radius: 18px; padding: 1.25rem; margin-bottom: 1.5rem; }
.note-box code { background: #eef2ff; padding: 0.12rem 0.3rem; border-radius: 6px; }
.pub-meta { color: var(--muted); margin: 0.25rem 0; }
.publication sup { font-weight: 700; color: var(--accent); margin-left: 1px; }
.pub-legend { color: var(--muted); font-size: 0.95rem; margin-top: 1rem; }


/* v5 refinements */
.brand{font-weight:600;letter-spacing:-.025em;line-height:1.15}
.brand-name strong,.air-name strong{font-weight:950;letter-spacing:.015em}
.brand-name em,.air-name em{font-style:normal;color:var(--copper);font-weight:750}
.brand small{font-size:11px;line-height:1.25;margin-top:2px;max-width:320px}
.brand-mark{background:linear-gradient(135deg,var(--primary),var(--secondary) 68%,var(--copper))}
.hero{background:radial-gradient(circle at top left,#e9f3ef 0,transparent 34%),radial-gradient(circle at 82% 18%,#f8ecd8 0,transparent 26%)}
.page-title + .section{padding-top:18px}
.note-box{padding:1rem 1.1rem;margin-bottom:1rem}
.note-box h2{margin:0 0 .35rem;font-size:1.35rem;letter-spacing:-.02em}
.note-box p{margin:.2rem 0 0}
.section-title{align-items:flex-start}
.card h3{margin-bottom:6px}
.publication h3{margin-bottom:4px}
.pub-meta,.journal{margin:.12rem 0}
.callout{background:linear-gradient(135deg,var(--primary),var(--secondary));padding:28px}
.footer{background:#102033}
@media(max-width:900px){.brand small{max-width:240px}.page-title{padding-top:26px}}


/* v6 CUHK-inspired refinements */
.site-header{background:rgba(255,255,255,.94);border-bottom:3px solid var(--primary)}
.brand{font-weight:400;letter-spacing:-.018em;line-height:1.15;color:var(--ink)}
.brand-name{font-weight:400}
.brand-name strong,.air-name strong{font-weight:900;letter-spacing:.01em;color:var(--ink)}
.brand-name em,.air-name em{font-style:normal;color:var(--accent);font-weight:500}
.air-name{font-weight:400;letter-spacing:-.02em}
.brand small{font-size:11px;line-height:1.25;margin-top:2px;max-width:340px;font-weight:500;color:#6b6472;letter-spacing:0}
.brand-mark{background:linear-gradient(135deg,var(--primary) 0%,var(--secondary) 68%,var(--gold) 69%,var(--gold) 100%);box-shadow:0 10px 24px rgba(111,44,145,.22)}
.nav-links a.active{color:var(--primary);font-weight:800}.nav-links a:hover{color:var(--primary)}
.hero{padding:52px 0 30px;background:radial-gradient(circle at top left,#f3e8ff 0,transparent 35%),radial-gradient(circle at 82% 18%,#fff3c4 0,transparent 24%)}
.eyebrow{color:var(--primary);border-color:#e8d6f2;background:#fff}
.hero-lab-title{font-weight:400!important;letter-spacing:-.055em}
.hero-lab-title .air-name{font-weight:400}
.hero-subtitle{font-size:22px!important;color:#4f465b!important;margin-top:-8px!important;margin-bottom:14px!important;font-weight:500}
.button.primary{background:var(--primary);box-shadow:0 14px 26px rgba(111,44,145,.20)}
.button.secondary{color:var(--primary)}
.card .icon{background:linear-gradient(135deg,#f5ecfa,#fff3c4);color:var(--primary)}
.pub-year{background:linear-gradient(135deg,var(--primary),var(--secondary))}.metric strong{color:var(--primary)}
.tag.gold{background:#fff7d7;color:#755609;border-color:#f2d36c}.timeline-item:before{background:var(--gold);box-shadow:0 0 0 2px #f2d36c}
.callout{background:linear-gradient(135deg,var(--primary),var(--secondary));padding:26px}.footer{background:#2c123c}
.page-title{padding:26px 0 8px;background:linear-gradient(180deg,#fff,transparent)}
.page-title p{margin:2px 0 0}.page-title + .section{padding-top:10px}.section{padding:34px 0}.section-title{margin-bottom:10px}.section-title p{margin:2px 0 0}.note-box{padding:.85rem 1rem;margin-bottom:.85rem}.note-box h2{margin:0 0 .2rem;font-size:1.28rem}.note-box p{margin:.1rem 0 0}.card{padding:20px}.card h3{margin-bottom:5px}.publication h3{margin-bottom:3px}
@media(max-width:900px){.brand small{max-width:250px}.hero-lab-title{font-size:clamp(38px,9vw,58px)}}


/* v7 CUHK hero and AIR typography refinements */
:root{
  --primary:#6f2c91;
  --secondary:#2b0f45;
  --gold:#f4c430;
  --accent:#b8860b;
}
.brand-name{font-weight:400;letter-spacing:-.015em}
.brand-name strong{font-weight:900;color:var(--primary)}
.brand-name em{font-weight:500;color:var(--accent)}
.air-name{font-weight:400!important;letter-spacing:-.025em}
.air-name strong{font-weight:900;color:inherit}
.air-name em{font-weight:500;color:var(--accent)}
.hero{
  padding:70px 0 42px;
  background:
    radial-gradient(circle at 82% 18%,rgba(244,196,48,.28) 0,transparent 28%),
    linear-gradient(135deg,#2b0f45 0%,#4b1766 52%,#6f2c91 100%);
  color:#fff;
}
.hero h1{font-weight:400!important;color:#fff;margin:0 0 18px;letter-spacing:-.058em}
.hero-lab-title .air-name{font-weight:400!important;color:#fff}
.hero-lab-title .air-name strong{color:#fff;font-weight:950}
.hero-lab-title .air-name em{display:none}
.hero-subtitle{color:#f7eaff!important;margin-top:0!important}
.hero p{color:#efe7f4}
.hero p strong{color:#fff}
.hero-art{filter:drop-shadow(0 22px 35px rgba(0,0,0,.24))}
.hero-art img{opacity:.96}
.button.secondary{background:#fff;color:var(--primary);border-color:#eadff0}
@media(max-width:900px){.hero{padding:54px 0 34px}.hero-lab-title{font-size:clamp(42px,13vw,64px)}}


/* v8 refinements: make AIR letters visible on CUHK-purple hero, remove homepage opening callout */
.hero-lab-title .air-name strong{
  color:var(--gold)!important;
  font-weight:950;
  text-shadow:0 2px 12px rgba(244,196,48,.28);
}
.hero-lab-title .air-name{
  color:#fff!important;
  font-weight:400!important;
}
.hero h1{
  text-shadow:0 8px 28px rgba(0,0,0,.16);
}


/* v9: white hero for figure-friendly homepage and removal of metric strip */
:root{
  --primary:#6f2c91;
  --secondary:#3b1556;
  --gold:#f4c430;
  --accent:#b8860b;
  --bg:#ffffff;
  --card:#ffffff;
  --soft:#fbf7ff;
  --line:#eadff0;
}
body{background:#fff;}
.hero{
  padding:58px 0 34px;
  background:
    radial-gradient(circle at 12% 8%, rgba(111,44,145,.08) 0, transparent 30%),
    radial-gradient(circle at 84% 18%, rgba(244,196,48,.16) 0, transparent 26%),
    linear-gradient(180deg,#ffffff 0%,#fbf7ff 100%)!important;
  color:var(--ink)!important;
  border-bottom:1px solid var(--line);
}
.hero h1{
  color:var(--ink)!important;
  text-shadow:none!important;
  margin:0 0 18px;
}
.hero-lab-title .air-name{
  color:var(--ink)!important;
  font-weight:400!important;
}
.hero-lab-title .air-name strong{
  color:var(--primary)!important;
  font-weight:950;
  text-shadow:none!important;
}
.hero-subtitle{
  color:#5f556d!important;
}
.hero p{
  color:#475569!important;
}
.hero p strong{
  color:var(--primary)!important;
}
.hero-art{filter:none!important;}
.hero-art img{opacity:1!important;}
.metric-row{display:none!important;}


/* v10 refinements: remove small research icons on homepage and use PI name in contact blocks */
.grid.three .card .icon{display:none!important;}
.grid.three .card h3{margin-top:0;}


/* v11 homepage action/button and white visual refinements */
.hero{
  background:#fff!important;
}
.hero-art{
  background:#fff!important;
  border:1px solid var(--line);
  border-radius:28px;
  padding:18px;
  box-shadow:0 18px 44px rgba(48,20,75,.08);
}
.hero-art img{
  background:#fff!important;
  border-radius:20px;
}
.actions .button.primary{
  background:var(--primary)!important;
  color:#fff!important;
  border-color:var(--primary)!important;
  box-shadow:0 14px 28px rgba(111,44,145,.22)!important;
}
.actions .button.secondary{
  background:#fff!important;
  color:var(--primary)!important;
  border-color:#eadff1!important;
  box-shadow:0 10px 22px rgba(48,20,75,.06)!important;
}


/* v12 refinements: footer name/contact spacing and blank subtitles */
.footer .air-name em{display:none;}
.footer .list-clean li{padding:2px 0; line-height:1.25; border-bottom:0;}
.footer h3{margin-bottom:6px;}
.footer p{line-height:1.45; margin-top:4px;}
.empty-subtitle{visibility:hidden; min-height:1.2em;}
.section-title .empty-subtitle{margin:6px 0 0;}
.page-title .empty-subtitle{margin:6px 0 0;}


/* v14 refinements: consistent header position and slightly looser footer contact spacing */
html{overflow-y:scroll;}
.site-header .container.nav{width:min(1120px,92vw);margin-left:auto!important;margin-right:auto!important;}
.footer .footer-contact li{padding:3px 0;line-height:1.38;}
.footer .footer-contact{margin-top:2px;}


/* v15 refinements: tighter section spacing and CSV-driven selected publications */
.section{padding:26px 0;}
.section-title{margin-bottom:6px;}
.section-title h2{margin-bottom:0;}
.section-title .empty-subtitle{min-height:.55em;margin:2px 0 0;}
.page-title .empty-subtitle{min-height:.55em;margin:2px 0 0;}
.page-title{padding:22px 0 4px;}
.page-title + .section{padding-top:8px;}
.card{padding:18px;}
.grid{gap:16px;}
.selected-publication-list{gap:16px;}
.pub-legend{grid-column:1 / -1; margin:.2rem 0 0;}
@media(max-width:900px){.section{padding:22px 0}.section-title{gap:10px;}}

/* v16 refinements */
.research-overview-title{margin-bottom:20px;}
.research-overview-section{padding-top:30px;}
@media(max-width:900px){.research-overview-title{margin-bottom:16px;}}

/* v17 refinements: more space below homepage research heading, tighter subpage title spacing */
.research-overview-title{margin-bottom:42px;}
.page-title{padding:24px 0 4px;}
.page-title + .section{padding-top:0;}
@media(max-width:900px){.research-overview-title{margin-bottom:32px;}.page-title{padding:20px 0 2px;}}

/* v23 refinements: slightly reduce space below homepage Research interests heading */
.research-overview-title{margin-bottom:34px;}
@media(max-width:900px){.research-overview-title{margin-bottom:26px;}}


/* v24: color AIR Lab in hero paragraph consistently with the header short name */
.hero p .air-inline{
  color:var(--accent)!important;
  font-weight:400;
}

/* v26: use an external image file for the top-left website icon */
.brand-mark{
  width:54px!important;
  height:54px!important;
  border-radius:0!important;
  background:url('../img/web_icon.png') center/contain no-repeat!important;
  box-shadow:none!important;
  flex:0 0 54px!important;
}
@media(max-width:900px){
  .brand-mark{width:46px!important;height:46px!important;flex-basis:46px!important;}
}

.under-construction-card {
  text-align: center;
  padding: 3rem 2rem;
}

.under-construction-card h2 {
  margin-bottom: 0.75rem;
}

/* v29: remove frame around homepage main.jpg */
.hero-art{
  background:transparent!important;
  border:none!important;
  border-radius:0!important;
  padding:0!important;
  box-shadow:none!important;
}
.hero-art img{
  border-radius:0!important;
  background:transparent!important;
  box-shadow:none!important;
}

/* v30 refinement: move top navigation links slightly closer to the purple underline */
.nav-links{
  transform: translateY(7px);
}
@media(max-width:900px){
  .nav-links{transform:none;}
}

/* v31 refinement: move top-left logo block closer to the purple underline */
.site-header .brand{
  transform: translateY(5px);
}
@media(max-width:900px){
  .site-header .brand{transform:none;}
}

.author-highlight {
  font-weight: 700;
}
.author-highlight sup {
  font-weight: 700;
}

/* v38 refinement: make Xiaoyu Wu and his superscript markers clearly bold in homepage selected publications too */
.selected-publication-list .author-highlight,
.selected-publication-list .author-highlight sup,
.publication-list .author-highlight,
.publication-list .author-highlight sup {
  font-weight: 900 !important;
}

.pub-title-link { color: inherit; text-decoration: none; cursor: pointer; }
.pub-title-link:hover { color: var(--cuhk-purple); text-decoration: underline; text-decoration-thickness: 1.5px; }

.text-box {
  max-width: 920px;
  margin: 0 auto;
}
.text-box h3 {
  margin-top: 1.25rem;
}
.text-box h3:first-child {
  margin-top: 0;
}
.text-box p {
  margin-bottom: 1rem;
}