/* ===== Yang Liu — personal site ===== */
:root{
  --bg:#070b18; --bg2:#0b1226; --bg3:#101a33; --panel:#0f172acc; --line:#1e293b;
  --text:#e2e8f0; --muted:#94a3b8; --dim:#64748b;
  --cyan:#38bdf8; --cyan2:#22d3ee; --indigo:#818cf8; --violet:#a78bfa; --pink:#f472b6; --green:#34d399; --amber:#fbbf24;
  --grad:linear-gradient(90deg,var(--cyan),var(--indigo),var(--pink));
  --r:16px; --nav:64px;
}
*{box-sizing:border-box}
html{scroll-behavior:smooth;scroll-padding-top:calc(var(--nav) + 12px)}
body{margin:0;background:var(--bg);color:var(--text);font-family:Inter,system-ui,-apple-system,"Segoe UI",Roboto,sans-serif;line-height:1.6;-webkit-font-smoothing:antialiased;overflow-x:hidden}
body::before{content:"";position:fixed;inset:0;z-index:-1;pointer-events:none;
  background-image:linear-gradient(var(--line) 1px,transparent 1px),linear-gradient(90deg,var(--line) 1px,transparent 1px);
  background-size:40px 40px;opacity:.28;mask-image:radial-gradient(ellipse at 50% 0%,#000 40%,transparent 85%)}
a{color:var(--cyan);text-decoration:none}
a:hover{color:#7dd3fc}
.mono{font-family:"JetBrains Mono",Consolas,Menlo,monospace}
.dim{color:var(--dim)}
.wrap{max-width:1140px;margin:0 auto;padding:0 24px}
h1,h2,h3{line-height:1.15;margin:0}
h2{font-size:clamp(28px,3.4vw,40px);font-weight:800;letter-spacing:-.02em}
h3{font-size:20px;font-weight:700}

/* progress + nav */
.progress{position:fixed;top:0;left:0;height:2px;width:0;background:var(--grad);z-index:100;box-shadow:0 0 12px var(--cyan)}
.nav{position:fixed;top:0;left:0;right:0;height:var(--nav);z-index:90;display:flex;align-items:center;justify-content:space-between;padding:0 28px;
  background:rgba(7,11,24,.55);backdrop-filter:blur(14px);-webkit-backdrop-filter:blur(14px);border-bottom:1px solid transparent;transition:border-color .3s,background .3s}
.nav.scrolled{border-bottom-color:var(--line);background:rgba(7,11,24,.85)}
.brand{font-family:"JetBrains Mono",monospace;font-weight:600;color:var(--text);font-size:15px;display:flex;align-items:center;gap:8px}
.brand-dot{width:9px;height:9px;border-radius:50%;background:var(--cyan);box-shadow:0 0 10px var(--cyan);animation:pulse 2s infinite}
.brand-accent{color:var(--cyan)}
.nav-links{list-style:none;display:flex;gap:6px;margin:0;padding:0;align-items:center}
.nav-links a{display:block;padding:8px 12px;border-radius:8px;color:var(--muted);font-size:14px;font-weight:500;transition:.2s}
.nav-links a:hover,.nav-links a.active{color:var(--text);background:rgba(148,163,184,.08)}
.nav-cta{border:1px solid var(--line);margin-left:6px}
.nav-toggle{display:none;background:none;border:0;cursor:pointer;flex-direction:column;gap:5px;padding:8px}
.nav-toggle span{width:22px;height:2px;background:var(--text);display:block;border-radius:2px}
@keyframes pulse{0%,100%{opacity:1}50%{opacity:.35}}

/* hero */
.hero{position:relative;min-height:100vh;display:flex;align-items:center;overflow:hidden;
  background:radial-gradient(ellipse 60% 50% at 75% 45%,rgba(56,189,248,.14),transparent 70%),linear-gradient(135deg,var(--bg) 0%,var(--bg2) 55%,var(--bg3) 100%)}
#net,#ecg{position:absolute;inset:0;width:100%;height:100%;pointer-events:none}
#ecg{z-index:1}
.hero-inner{position:relative;z-index:2;width:100%;max-width:1140px;margin:0 auto;padding:120px 24px 90px;display:grid;grid-template-columns:1.35fr .9fr;gap:40px;align-items:center}
.terminal{color:var(--dim);font-size:13px;margin-bottom:14px}
.terminal .prompt{color:var(--dim)}
.terminal .cursor{color:var(--cyan2);animation:blink 1.1s steps(1) infinite;margin-left:2px}
@keyframes blink{50%{opacity:0}}
.hero-name{font-size:clamp(56px,8.5vw,104px);font-weight:800;letter-spacing:-.035em;line-height:1}
.grad{background:var(--grad);background-size:200% 100%;-webkit-background-clip:text;background-clip:text;color:transparent;animation:shine 6s ease-in-out infinite}
@keyframes shine{0%,100%{background-position:0% 50%}50%{background-position:100% 50%}}
.hero-tag{font-size:clamp(16px,1.7vw,21px);font-weight:600;color:#cbd5e1;margin:18px 0 6px}
.hero-sub{color:var(--muted);font-size:14px;min-height:22px;margin:0 0 18px}
.hero-sub::after{content:"▌";color:var(--cyan2);animation:blink 1s steps(1) infinite;margin-left:2px}
.chips{display:flex;flex-wrap:wrap;gap:8px;margin-bottom:26px}
.chip{font-family:"JetBrains Mono",monospace;font-size:12px;font-weight:600;padding:5px 14px;border-radius:999px;background:rgba(15,23,42,.8);border:1px solid}
.c-cyan{color:var(--cyan2);border-color:rgba(34,211,238,.6)} .c-indigo{color:var(--indigo);border-color:rgba(129,140,248,.6)}
.c-violet{color:var(--violet);border-color:rgba(167,139,250,.6)} .c-pink{color:var(--pink);border-color:rgba(244,114,182,.6)}
.c-green{color:var(--green);border-color:rgba(52,211,153,.6)} .c-amber{color:var(--amber);border-color:rgba(251,191,36,.6)}
.hero-actions{display:flex;flex-wrap:wrap;gap:10px}
.btn{display:inline-flex;align-items:center;padding:11px 20px;border-radius:10px;font-weight:600;font-size:14px;border:1px solid var(--line);color:var(--text);transition:.2s;background:rgba(15,23,42,.6)}
.btn:hover{transform:translateY(-2px);border-color:var(--cyan);color:var(--text);box-shadow:0 8px 30px rgba(56,189,248,.18)}
.btn-primary{background:var(--grad);border:0;color:#0b1020}
.btn-primary:hover{color:#0b1020;filter:brightness(1.08)}
.hero-photo{position:relative;display:flex;justify-content:center;align-items:center}
.hero-photo img{width:min(320px,70vw);aspect-ratio:1;object-fit:cover;border-radius:50%;border:3px solid rgba(15,23,42,.9);position:relative;z-index:1;
  box-shadow:0 30px 80px rgba(0,0,0,.6);animation:float 7s ease-in-out infinite}
.ring{position:absolute;width:min(380px,82vw);aspect-ratio:1;border-radius:50%;
  background:conic-gradient(from 0deg,var(--cyan),var(--indigo),var(--pink),var(--cyan));
  mask:radial-gradient(farthest-side,transparent calc(100% - 3px),#000 calc(100% - 2px));-webkit-mask:radial-gradient(farthest-side,transparent calc(100% - 3px),#000 calc(100% - 2px));
  animation:spin 12s linear infinite;opacity:.9;filter:drop-shadow(0 0 14px rgba(56,189,248,.5))}
@keyframes spin{to{transform:rotate(360deg)}}
@keyframes float{0%,100%{transform:translateY(0)}50%{transform:translateY(-10px)}}
.photo-badge{position:absolute;bottom:6%;right:4%;z-index:2;background:rgba(7,11,24,.85);border:1px solid var(--line);border-radius:12px;padding:10px 14px;font-size:11px;color:var(--muted);line-height:1.5;backdrop-filter:blur(8px)}
.photo-badge b{color:var(--cyan);font-weight:600}
.scroll-hint{position:absolute;left:50%;bottom:26px;transform:translateX(-50%);width:24px;height:40px;border:2px solid var(--dim);border-radius:14px;z-index:2}
.scroll-hint span{position:absolute;left:50%;top:7px;width:4px;height:8px;margin-left:-2px;border-radius:2px;background:var(--cyan);animation:drop 1.8s infinite}
@keyframes drop{0%{transform:translateY(0);opacity:1}80%{transform:translateY(16px);opacity:0}100%{opacity:0}}

/* sections */
.section{padding:96px 0;position:relative}
.section.alt{background:linear-gradient(180deg,rgba(15,23,42,.35),rgba(15,23,42,.0));border-top:1px solid rgba(30,41,59,.6);border-bottom:1px solid rgba(30,41,59,.6)}
.sec-head{display:flex;align-items:baseline;gap:16px;margin-bottom:40px;flex-wrap:wrap}
.sec-idx{color:var(--cyan);font-size:14px;font-weight:600}
.sec-idx::before{content:"// "}
.sec-note{margin:0 0 0 auto;color:var(--dim);font-size:13px}

/* reveal */
.reveal{opacity:0;transform:translateY(22px);transition:opacity .7s ease,transform .7s ease}
.reveal.in{opacity:1;transform:none}

/* about */
.about-grid{display:grid;grid-template-columns:1.4fr 1fr;gap:48px;align-items:start}
.about-text p{margin:0 0 16px;color:#cbd5e1;font-size:17px}
.about-text b{color:var(--text)}
.stats{display:grid;grid-template-columns:1fr 1fr;gap:14px}
.stat{background:var(--panel);border:1px solid var(--line);border-radius:var(--r);padding:20px 18px;transition:.25s;position:relative;overflow:hidden}
.stat::before{content:"";position:absolute;inset:0;background:radial-gradient(circle at 0% 0%,rgba(56,189,248,.16),transparent 60%);opacity:0;transition:.3s}
.stat:hover{transform:translateY(-3px);border-color:rgba(56,189,248,.5)} .stat:hover::before{opacity:1}
.stat-num{font-size:40px;font-weight:800;letter-spacing:-.03em;background:var(--grad);-webkit-background-clip:text;background-clip:text;color:transparent;line-height:1}
.stat-num sup{font-size:18px;vertical-align:top}
.stat-lbl{color:var(--muted);font-size:13px;margin-top:8px;line-height:1.45}

/* research cards */
.cards{display:grid;grid-template-columns:repeat(4,1fr);gap:16px}
.card{background:var(--panel);border:1px solid var(--line);border-radius:var(--r);padding:24px;position:relative;overflow:hidden;transition:.3s}
.card::after{content:"";position:absolute;left:0;right:0;top:0;height:2px;background:var(--grad);opacity:0;transition:.3s}
.card:hover{transform:translateY(-5px);border-color:rgba(129,140,248,.5);box-shadow:0 20px 50px rgba(0,0,0,.4)} .card:hover::after{opacity:1}
.card-icon{font-size:26px;margin-bottom:14px;border:none}
.card h3{font-size:18px;margin-bottom:10px}
.card p{color:var(--muted);font-size:14px;margin:0 0 16px}
.tags{display:flex;flex-wrap:wrap;gap:6px}
.tags span{font-size:11px;padding:3px 9px;border-radius:6px;background:rgba(56,189,248,.08);color:var(--cyan);border:1px solid rgba(56,189,248,.25)}

/* publications */
.filters{display:flex;flex-wrap:wrap;gap:8px;margin-bottom:28px}
.filter{font-family:"JetBrains Mono",monospace;font-size:12px;font-weight:500;padding:7px 14px;border-radius:999px;border:1px solid var(--line);background:transparent;color:var(--muted);cursor:pointer;transition:.2s}
.filter:hover{border-color:var(--cyan);color:var(--text)}
.filter.active{background:var(--cyan);color:#0b1020;border-color:var(--cyan);font-weight:600}
.pubs{display:flex;flex-direction:column;gap:14px}
.pub{display:grid;grid-template-columns:220px 1fr;gap:22px;background:var(--panel);border:1px solid var(--line);border-radius:var(--r);padding:16px;transition:.3s;align-items:center}
.pub:hover{border-color:rgba(56,189,248,.45);transform:translateX(4px);box-shadow:0 14px 40px rgba(0,0,0,.35)}
.pub.hide{display:none}
.pub-thumb{width:100%;aspect-ratio:16/10;border-radius:10px;overflow:hidden;background:#0b1226;border:1px solid var(--line);display:flex;align-items:center;justify-content:center;position:relative}
.pub-thumb img{width:100%;height:100%;object-fit:cover;transition:transform .5s}
.pub:hover .pub-thumb img{transform:scale(1.06)}
.pub-thumb .ph{font-family:"JetBrains Mono",monospace;font-weight:700;font-size:22px;letter-spacing:.04em;background:var(--grad);-webkit-background-clip:text;background-clip:text;color:transparent}
.pub-meta{display:flex;align-items:center;gap:10px;flex-wrap:wrap;margin-bottom:8px}
.venue{font-family:"JetBrains Mono",monospace;font-size:11px;font-weight:700;padding:3px 10px;border-radius:6px;border:1px solid}
.venue.miccai{color:var(--cyan2);border-color:rgba(34,211,238,.5);background:rgba(34,211,238,.08)}
.venue.cvpr,.venue.icme{color:var(--indigo);border-color:rgba(129,140,248,.5);background:rgba(129,140,248,.08)}
.venue.iccv,.venue.isbi{color:var(--violet);border-color:rgba(167,139,250,.5);background:rgba(167,139,250,.08)}
.venue.media{color:var(--pink);border-color:rgba(244,114,182,.5);background:rgba(244,114,182,.08)}
.venue.wacv{color:var(--green);border-color:rgba(52,211,153,.5);background:rgba(52,211,153,.08)}
.venue.tcsvt{color:var(--amber);border-color:rgba(251,191,36,.5);background:rgba(251,191,36,.08)}
.venue.arxiv{color:#f87171;border-color:rgba(248,113,113,.5);background:rgba(248,113,113,.08)}
.hl{font-size:11px;color:var(--amber);font-family:"JetBrains Mono",monospace}
.pub-year{color:var(--dim);font-family:"JetBrains Mono",monospace;font-size:12px}
.pub h3{font-size:17px;margin-bottom:6px;line-height:1.35}
.pub h3 a{color:var(--text)} .pub h3 a:hover{color:var(--cyan)}
.pub-authors{color:var(--muted);font-size:13.5px;margin:0 0 10px}
.pub-authors .me{color:var(--text);font-weight:600;border-bottom:1px solid var(--cyan)}
.pub-links{display:flex;gap:8px;flex-wrap:wrap}
.pub-links a{font-family:"JetBrains Mono",monospace;font-size:12px;padding:4px 11px;border-radius:6px;border:1px solid var(--line);color:var(--muted);transition:.2s}
.pub-links a:hover{border-color:var(--cyan);color:var(--cyan)}

/* news timeline */
.timeline{list-style:none;margin:0;padding:0 0 0 28px;position:relative;max-width:900px}
.timeline::before{content:"";position:absolute;left:6px;top:6px;bottom:6px;width:2px;background:linear-gradient(180deg,var(--cyan),var(--indigo),var(--pink));opacity:.6}
.timeline li{position:relative;padding:0 0 26px 22px}
.timeline li::before{content:"";position:absolute;left:-28px;top:7px;width:14px;height:14px;border-radius:50%;background:var(--bg);border:2px solid var(--cyan);box-shadow:0 0 12px rgba(56,189,248,.6)}
.timeline li:nth-child(3n+2)::before{border-color:var(--indigo);box-shadow:0 0 12px rgba(129,140,248,.6)}
.timeline li:nth-child(3n)::before{border-color:var(--pink);box-shadow:0 0 12px rgba(244,114,182,.6)}
.tl-date{font-family:"JetBrains Mono",monospace;font-size:12px;color:var(--cyan);font-weight:600;margin-bottom:3px}
.tl-text{color:#cbd5e1;font-size:15px}
.tl-text a{color:var(--text);border-bottom:1px dashed var(--dim)} .tl-text a:hover{color:var(--cyan)}
.tl-more{margin-top:8px;background:none;border:1px solid var(--line);color:var(--muted);padding:8px 16px;border-radius:8px;cursor:pointer;font-family:"JetBrains Mono",monospace;font-size:12px}
.tl-more:hover{border-color:var(--cyan);color:var(--cyan)}
.timeline li.extra{display:none} .timeline.open li.extra{display:block}

/* experience */
.exp-grid{display:grid;grid-template-columns:1fr 1fr;gap:16px}
.exp{background:var(--panel);border:1px solid var(--line);border-radius:var(--r);padding:24px;transition:.3s}
.exp:hover{border-color:rgba(167,139,250,.5);transform:translateY(-3px)}
.exp-when{color:var(--cyan);font-size:12px;font-weight:600;margin-bottom:8px}
.exp-role{color:var(--muted);font-size:14px;margin:4px 0 10px}
.exp p{margin:0;color:#cbd5e1;font-size:14.5px}

/* contact */
.contact{text-align:center;max-width:760px}
.contact h2{margin:8px 0 12px}
.contact p{color:var(--muted);font-size:17px;margin:0 0 28px}
.contact-links{display:flex;flex-wrap:wrap;justify-content:center;gap:12px}
.clink{display:flex;flex-direction:column;align-items:flex-start;gap:2px;padding:12px 18px;border:1px solid var(--line);border-radius:12px;background:var(--panel);color:var(--text);font-size:14px;font-weight:500;transition:.2s;min-width:180px;text-align:left}
.clink .mono{font-size:11px;color:var(--cyan)}
a.clink:hover{border-color:var(--cyan);transform:translateY(-2px)}

/* visitors (ClustrMaps) */
.visitors{margin:34px auto 0;max-width:640px;background:var(--panel);border:1px solid var(--line);border-radius:var(--r);padding:16px;text-align:left}
.visitors-head{display:flex;align-items:center;gap:8px;font-size:12px;color:var(--cyan);font-weight:600;margin-bottom:12px}
.visitors-head::before{content:"// "}
.visitors-stats{display:grid;grid-template-columns:1fr 1fr;gap:12px;margin-bottom:12px}
.vstat{background:rgba(7,11,24,.7);border:1px solid var(--line);border-radius:10px;padding:14px 16px;display:flex;flex-direction:column;gap:4px}
.vnum{font-size:30px;font-weight:800;letter-spacing:-.02em;background:var(--grad);-webkit-background-clip:text;background-clip:text;color:transparent;line-height:1}
.vlbl{font-size:11px;color:var(--dim)}
.visitors-badge{display:flex;justify-content:center;margin-bottom:12px}
.visitors-map{border-radius:10px;overflow:hidden;background:#070b18;display:flex;justify-content:center;padding:6px 0}
.visitors-map:empty,.visitors-map.dead{display:none}
.visitors-map img,.visitors-map canvas,.visitors-map a{max-width:100%;display:block;margin:0 auto}

/* footer */
.footer{border-top:1px solid var(--line);padding:26px 0 34px;font-size:12px}
.footer-inner{display:flex;justify-content:space-between;gap:12px;flex-wrap:wrap}
.totop{position:fixed;right:22px;bottom:22px;width:42px;height:42px;border-radius:50%;background:var(--panel);border:1px solid var(--line);display:flex;align-items:center;justify-content:center;color:var(--text);opacity:0;pointer-events:none;transition:.3s;z-index:80;backdrop-filter:blur(8px)}
.totop.show{opacity:1;pointer-events:auto} .totop:hover{border-color:var(--cyan);color:var(--cyan)}

/* responsive */
@media (max-width:980px){
  .hero-inner{grid-template-columns:1fr;text-align:center;padding-top:110px}
  .hero-text{order:2} .hero-photo{order:1}
  .chips,.hero-actions{justify-content:center}
  .about-grid{grid-template-columns:1fr}
  .cards{grid-template-columns:1fr 1fr}
}
@media (max-width:720px){
  .nav{padding:0 18px}
  .nav-toggle{display:flex}
  .nav-links{position:absolute;top:var(--nav);left:0;right:0;flex-direction:column;align-items:stretch;background:rgba(7,11,24,.96);border-bottom:1px solid var(--line);padding:10px 14px 16px;display:none}
  .nav-links.open{display:flex}
  .nav-cta{margin-left:0}
  .cards,.exp-grid,.stats{grid-template-columns:1fr}
  .pub{grid-template-columns:1fr}
  .pub-thumb{aspect-ratio:16/8}
  .section{padding:70px 0}
  .photo-badge{display:none}
}
@media (prefers-reduced-motion:reduce){
  *{animation:none!important;transition:none!important}
  .reveal{opacity:1;transform:none}
}