:root{
  --bg:#f4f3ef; --bg-tint:#eaeef0; --panel:#ffffff; --ink:#1b2430; --muted:#5b6470;
  --line:#e4dfd6; --accent:#1f4a63; --accent-ink:#1f4a63; --accent-soft:rgba(31,74,99,.10);
  --c1:#1f4a63; --c2:#2f7d6e; --c3:#9a5b2b; --c4:#6b4e86;
  --shadow:0 1px 2px rgba(20,30,40,.04), 0 8px 24px rgba(20,30,40,.06);
  --shadow-h:0 2px 6px rgba(20,30,40,.08), 0 14px 34px rgba(20,30,40,.10);
  --maxw:760px;
  --serif:Georgia,"Iowan Old Style","Times New Roman",serif;
  --sans:ui-sans-serif,system-ui,-apple-system,"Segoe UI",Roboto,Helvetica,Arial,sans-serif;
  --hero:radial-gradient(900px 360px at 88% -45%, rgba(31,74,99,.16), transparent 60%),
         radial-gradient(720px 320px at -8% -10%, rgba(47,125,110,.13), transparent 60%),
         var(--panel);
}
@media (prefers-color-scheme:dark){
  :root{
    --bg:#0f1318; --bg-tint:#151c24; --panel:#161c24; --ink:#e7eaee; --muted:#9aa3ad;
    --line:#28303a; --accent:#1f4a63; --accent-ink:#8fc0d8; --accent-soft:rgba(143,192,216,.13);
    --c1:#6fa6c4; --c2:#5fb3a3; --c3:#cf9a63; --c4:#a98fc9;
    --shadow:0 1px 2px rgba(0,0,0,.3), 0 8px 24px rgba(0,0,0,.35);
    --shadow-h:0 2px 6px rgba(0,0,0,.4), 0 16px 36px rgba(0,0,0,.5);
    --hero:radial-gradient(900px 360px at 88% -45%, rgba(143,192,216,.12), transparent 60%),
           radial-gradient(720px 320px at -8% -10%, rgba(95,179,163,.10), transparent 60%),
           var(--panel);
  }
}
*{box-sizing:border-box}
html{-webkit-text-size-adjust:100%; scroll-behavior:smooth}
body{margin:0; background:var(--bg); color:var(--ink);
  font-family:var(--sans); font-size:17px; line-height:1.6;
  text-rendering:optimizeLegibility; -webkit-font-smoothing:antialiased}
.wrap{max-width:var(--maxw); margin:0 auto; padding:0 22px}
a{color:var(--accent-ink); text-underline-offset:2px}
a:hover{text-decoration:none}
:focus-visible{outline:3px solid var(--accent-ink); outline-offset:2px; border-radius:3px}
.skip{position:absolute; left:-999px; top:0; background:var(--accent); color:#fff; padding:10px 14px; z-index:60}
.skip:focus{left:8px; top:8px}

/* ---------- side navigation ---------- */
.sidenav{position:sticky; top:0; z-index:40;
  background:var(--panel);
  background:color-mix(in srgb, var(--panel) 88%, transparent);
  backdrop-filter:saturate(1.1) blur(8px); -webkit-backdrop-filter:saturate(1.1) blur(8px);
  border-bottom:1px solid var(--line)}
.sidenav ul{display:flex; gap:4px; list-style:none; margin:0; padding:8px 12px;
  overflow-x:auto; scrollbar-width:none}
.sidenav ul::-webkit-scrollbar{display:none}
.sidenav li{flex:0 0 auto}
.sidenav a{display:block; padding:6px 11px; font-size:.82rem; font-weight:600;
  color:var(--muted); text-decoration:none; border-radius:999px; white-space:nowrap; transition:.18s}
.sidenav a:hover{color:var(--accent-ink); background:var(--accent-soft)}
.sidenav a.active{color:var(--accent-ink); background:var(--accent-soft)}

@media (min-width:1140px){
  .sidenav{position:fixed; top:50%; transform:translateY(-50%);
    left:calc((100vw - var(--maxw))/2 - 184px); width:160px;
    background:none; backdrop-filter:none; -webkit-backdrop-filter:none; border:0}
  .sidenav ul{display:block; padding:0; overflow:visible}
  .sidenav li{margin:1px 0}
  .sidenav a{padding:6px 12px; border-left:2px solid var(--line); border-radius:0 7px 7px 0}
  .sidenav a.active{border-left-color:var(--accent-ink); font-weight:700}
}

/* ---------- hero ---------- */
.hero{background:var(--hero); border-bottom:1px solid var(--line); padding:46px 0 38px}
.hero-grid{display:flex; gap:30px; align-items:center; justify-content:space-between}
.hero-text{flex:1 1 auto; min-width:0}
.hero-photo{flex:0 0 auto}
.hero-photo img{width:184px; height:184px; border-radius:50%; object-fit:cover;
  border:4px solid var(--panel); box-shadow:0 0 0 2px var(--accent), var(--shadow)}
h1{font-family:var(--serif); font-size:2.5rem; line-height:1.08; margin:0 0 6px; letter-spacing:-.012em}
.ko{font-size:1.5rem; color:var(--muted); font-family:var(--sans); font-weight:400; margin-left:8px}
.tagline{display:inline-block; font-weight:700; color:var(--accent-ink); font-size:1.2rem; margin:.45rem 0 .1rem}
.tagline::after{content:""; display:block; width:54px; height:3px; border-radius:2px; margin-top:7px;
  background:linear-gradient(90deg,var(--c1),var(--c2))}
.subtagline{color:var(--muted); margin:.5rem 0 .9rem; font-size:1rem}
.positioning{margin:.4rem 0 .6rem; max-width:60ch}
.affil{color:var(--muted); font-size:.95rem; margin:.2rem 0 1.1rem}
.links{display:flex; flex-wrap:wrap; gap:9px}
.btn{display:inline-block; padding:8px 14px; border:1px solid var(--line); border-radius:999px;
  background:var(--panel); color:var(--ink); text-decoration:none; font-size:.9rem; font-weight:600;
  box-shadow:var(--shadow); transition:.18s}
.btn:hover{border-color:var(--accent-ink); color:var(--accent-ink); transform:translateY(-1px); box-shadow:var(--shadow-h)}
.btn-cv{background:var(--accent); border-color:var(--accent); color:#fff}
.btn-cv:hover{color:#fff; filter:brightness(1.08)}

/* ---------- sections ---------- */
main{padding:6px 0 8px}
section{padding:34px 0}
h2{font-family:var(--serif); font-size:1.6rem; margin:0 0 .55rem; letter-spacing:-.01em; display:flex; align-items:center; gap:11px}
h2::before{content:""; flex:0 0 auto; width:24px; height:5px; border-radius:3px; background:var(--accent)}
#identity h2::before,#leadership h2::before{background:var(--c1)}
#research h2::before{background:var(--c2)}
#publications h2::before,#opensource h2::before{background:var(--c3)}
#talks h2::before,#about h2::before{background:var(--c4)}
.lead{color:var(--muted); margin:.2rem 0 1.2rem; font-size:1.04rem}

/* panel sections */
.panel{background:var(--panel); border:1px solid var(--line); border-radius:16px;
  padding:26px 28px; box-shadow:var(--shadow)}
.panel + .panel{margin-top:8px}

/* ---------- pillars ---------- */
.pillars{display:grid; grid-template-columns:1fr 1fr; gap:16px; margin-bottom:20px}
.pillar{background:var(--panel); border:1px solid var(--line); border-top:3px solid var(--c);
  border-radius:12px; padding:16px 17px; box-shadow:var(--shadow); transition:.18s}
.pillar:hover{transform:translateY(-3px); box-shadow:var(--shadow-h)}
.pillars .pillar:nth-child(1){--c:var(--c1)}
.pillars .pillar:nth-child(2){--c:var(--c2)}
.pillars .pillar:nth-child(3){--c:var(--c3)}
.pillars .pillar:nth-child(4){--c:var(--c4)}
.pillar h3{color:var(--ink); font-size:1.02rem; margin:.1rem 0 .35rem}
.pillar p{margin:.35rem 0; color:var(--muted); font-size:.93rem}
.pillar .sys{color:var(--c); font-weight:700; font-size:.85rem}

/* ---------- diagrams ---------- */
.diagram{margin:18px 0 4px; text-align:center}
.diagram img{max-width:100%; height:auto; border-radius:14px; box-shadow:var(--shadow)}

/* ---------- selected research ---------- */
.item{background:var(--panel); border:1px solid var(--line); border-left:5px solid var(--c,var(--accent));
  border-radius:12px; padding:18px 22px; margin:16px 0; box-shadow:var(--shadow); transition:.18s}
.item:hover{box-shadow:var(--shadow-h)}
.item:nth-of-type(1){--c:var(--c1)} .item:nth-of-type(2){--c:var(--c2)}
.item:nth-of-type(3){--c:var(--c3)} .item:nth-of-type(4){--c:var(--c4)}
.item:nth-of-type(5){--c:var(--c1)}
.item h3{display:flex; flex-wrap:wrap; align-items:baseline; gap:9px; font-size:1.22rem; font-family:var(--serif); margin:0 0 .5rem}
.venue{font-family:var(--sans); font-size:.82rem; font-weight:600; color:var(--muted)}
.cat{font-family:var(--sans); font-size:.68rem; font-weight:700; text-transform:uppercase; letter-spacing:.05em;
  color:#fff; background:var(--c,var(--accent)); border-radius:999px; padding:3px 9px}
.item p{margin:.35rem 0}
.lab{font-weight:700; color:var(--c,var(--accent))}
.role{color:var(--muted); font-size:.95rem}
.more{margin-top:.6rem; font-size:.92rem; font-weight:700}
.more a{margin-right:16px}

/* ---------- publications ---------- */
.grp{color:var(--muted); text-transform:uppercase; font-size:.78rem; letter-spacing:.07em; margin:20px 0 8px;
  padding-bottom:5px; border-bottom:1px solid var(--line)}
ol.pubs{margin:0; padding-left:1.4em}
ol.pubs li{margin:.3rem 0; padding:.35rem .5rem; font-size:.95rem; line-height:1.55; border-radius:8px; transition:.15s}
ol.pubs li:hover{background:var(--bg-tint)}
.au{color:var(--muted)}
ol.pubs i{color:var(--ink)}
.tag{display:inline-block; font-size:.72rem; color:var(--accent-ink); background:var(--accent-soft);
  border-radius:999px; padding:1px 9px; margin-left:5px; white-space:nowrap; font-weight:600}

/* ---------- generic lists ---------- */
ul.plain{list-style:none; margin:.3rem 0; padding:0}
ul.plain li{margin:0; font-size:.97rem; border-top:1px solid var(--line); padding:.6rem .2rem}
ul.plain li:first-child{border-top:0}
.muted{color:var(--muted); font-size:.85rem; font-weight:600}
.note{color:var(--muted); font-size:.92rem}

/* chips (teaching interests) */
.chips{display:flex; flex-wrap:wrap; gap:8px; margin:.6rem 0 .2rem}
.chips .chip{font-size:.84rem; font-weight:600; color:var(--ink); background:var(--bg-tint);
  border:1px solid var(--line); border-radius:999px; padding:5px 12px}

/* ---------- two column ---------- */
.two-col{display:grid; grid-template-columns:1fr 1fr; gap:32px}
.two-col h2{font-size:1.35rem}

/* ---------- about ---------- */
dl.edu{display:grid; grid-template-columns:max-content 1fr; gap:8px 20px; margin:1rem 0}
dl.edu dt{font-weight:700}
dl.edu dt::before{content:""; display:inline-block; width:8px; height:8px; border-radius:50%;
  background:var(--c4); margin-right:9px; vertical-align:middle}
dl.edu dd{margin:0; color:var(--muted)}
.contact{margin-top:1rem}

/* ---------- footer ---------- */
footer{padding:26px 0 46px; color:var(--muted); font-size:.88rem;
  border-top:3px solid transparent; border-image:linear-gradient(90deg,var(--c1),var(--c2),var(--c3),var(--c4)) 1}
footer a{color:var(--muted)}
footer a:hover{color:var(--accent-ink)}

/* ---------- anchor offsets ---------- */
section{scroll-margin-top:62px}
#top{scroll-margin-top:0}
@media (min-width:1140px){section{scroll-margin-top:28px}}

/* ---------- responsive ---------- */
@media (max-width:680px){
  body{font-size:16px}
  .hero{padding:28px 0 26px}
  .hero-grid{flex-direction:column-reverse; align-items:flex-start; gap:16px}
  .hero-photo img{width:104px; height:104px}
  h1{font-size:2rem}
  h2{font-size:1.4rem}
  .pillars{grid-template-columns:1fr}
  .two-col{grid-template-columns:1fr; gap:10px}
  .panel{padding:20px 18px}
  .item{padding:16px 17px}
  dl.edu{grid-template-columns:1fr; gap:2px 0}
  dl.edu dd{margin-bottom:.5rem}
}
@media (prefers-reduced-motion:reduce){
  html{scroll-behavior:auto}
  *{transition:none!important; animation:none!important}
  .btn:hover,.pillar:hover{transform:none}
}