/* Sunil Tyagi — personal site. Tokens */
:root{
  --paper:#F2F5F7; --ink:#10233B; --deep:#0B1D33; --panel:#0E2440;
  --cyan:#2496B4; --cyan-bright:#39C6E0; --orange:#D97516; --orange-bright:#F28C28;
  --muted:#5B7186; --line:#D5DEE5; --white:#EDF2F6;
  --measure:70ch; --wide:1080px;
  --serif:"STIX Two Text",Georgia,serif;
  --sans:"Source Sans 3","Segoe UI",system-ui,sans-serif;
  --mono:"IBM Plex Mono",ui-monospace,Menlo,monospace;
}
*{box-sizing:border-box;margin:0;padding:0}
html{scroll-behavior:smooth}
@media (prefers-reduced-motion:reduce){html{scroll-behavior:auto}}
body{background:var(--paper);color:var(--ink);font-family:var(--sans);
  font-size:1.075rem;line-height:1.65;-webkit-font-smoothing:antialiased}
a{color:var(--cyan);text-decoration:none}
a:hover{text-decoration:underline}
a:focus-visible{outline:2px solid var(--orange);outline-offset:2px}
img{max-width:100%;height:auto;display:block}

/* Header / nav */
.site-head{background:var(--deep);color:var(--white)}
.site-head .bar{max-width:var(--wide);margin:0 auto;padding:.9rem 1.25rem;
  display:flex;flex-wrap:wrap;gap:.4rem 1.6rem;align-items:baseline}
.brand{font-family:var(--serif);font-size:1.15rem;font-weight:600;color:var(--white);letter-spacing:.01em}
.brand:hover{text-decoration:none;color:var(--cyan-bright)}
nav.main{margin-left:auto;display:flex;flex-wrap:wrap;gap:1.1rem}
nav.main a{font-family:var(--mono);font-size:.78rem;letter-spacing:.09em;
  text-transform:uppercase;color:#9FB3C8}
nav.main a[aria-current="page"]{color:var(--orange-bright)}
nav.main a:hover{color:var(--cyan-bright);text-decoration:none}

/* Hero (home) */
.hero{background:var(--deep);color:var(--white);position:relative;overflow:hidden}
.hero .inner{max-width:var(--wide);margin:0 auto;padding:4.5rem 1.25rem 5.5rem;position:relative;z-index:1}
.hero .eyebrow{font-family:var(--mono);font-size:.8rem;letter-spacing:.14em;
  text-transform:uppercase;color:var(--orange-bright);margin-bottom:1rem}
.hero h1{font-family:var(--serif);font-weight:600;font-size:clamp(1.9rem,4.4vw,3.1rem);
  line-height:1.18;max-width:24ch}
.hero .thesis{margin-top:1.4rem;font-family:var(--serif);font-style:italic;
  font-size:clamp(1.05rem,2vw,1.3rem);color:#C9D6E2;max-width:52ch}
.hero .roles{margin-top:1.6rem;font-family:var(--mono);font-size:.82rem;
  letter-spacing:.05em;color:#9FB3C8}
.hero .roles a{color:var(--cyan-bright)}
.hero svg.comb{position:absolute;left:0;right:0;bottom:-4px;width:100%;height:110px;opacity:.5}

/* Page title band (inner pages) */
.pagehead{background:var(--deep);color:var(--white)}
.pagehead .inner{max-width:var(--wide);margin:0 auto;padding:2.6rem 1.25rem 2.8rem}
.pagehead .eyebrow{font-family:var(--mono);font-size:.78rem;letter-spacing:.14em;
  text-transform:uppercase;color:var(--orange-bright);margin-bottom:.6rem}
.pagehead h1{font-family:var(--serif);font-weight:600;font-size:clamp(1.7rem,3.4vw,2.4rem)}
.pagehead p.lede{margin-top:.8rem;color:#C9D6E2;max-width:var(--measure)}

/* Sections */
main{max-width:var(--wide);margin:0 auto;padding:0 1.25rem}
section{padding:3rem 0 1rem}
.section-head{margin-bottom:1.6rem}
.eyebrow{font-family:var(--mono);font-size:.76rem;letter-spacing:.14em;
  text-transform:uppercase;color:var(--orange)}
h2{font-family:var(--serif);font-weight:600;font-size:1.65rem;margin-top:.35rem}
h3{font-family:var(--serif);font-weight:600;font-size:1.18rem}
p{max-width:var(--measure)}
p+p{margin-top:1rem}
.envelope-rule{width:190px;height:16px;margin-top:.7rem;display:block}

/* Track cards (home) */
.tracks{display:grid;grid-template-columns:repeat(auto-fit,minmax(270px,1fr));gap:1.2rem;margin-top:1.6rem}
.card{background:#FFFFFF;border:1px solid var(--line);border-top:3px solid var(--cyan);
  padding:1.3rem 1.3rem 1.4rem}
.card h3{margin-bottom:.5rem}
.card p{font-size:.98rem;color:#33475E}
.card .k{font-family:var(--mono);font-size:.72rem;letter-spacing:.12em;
  text-transform:uppercase;color:var(--muted);display:block;margin-bottom:.55rem}

/* Featured note strip */
.feature{background:var(--panel);color:var(--white);border-left:4px solid var(--orange-bright);
  padding:1.4rem 1.5rem;margin-top:1.6rem}
.feature .k{font-family:var(--mono);font-size:.72rem;letter-spacing:.12em;
  text-transform:uppercase;color:var(--orange-bright)}
.feature h3{margin:.4rem 0 .5rem}
.feature p{color:#C9D6E2;font-size:.98rem}
.feature a.more{font-family:var(--mono);font-size:.8rem;color:var(--cyan-bright)}

/* Timeline (experience) */
.timeline{list-style:none;margin-top:.6rem}
.timeline li{position:relative;padding:0 0 2.1rem 1.7rem;border-left:2px solid var(--line)}
.timeline li:last-child{padding-bottom:.4rem}
.timeline li::before{content:"";position:absolute;left:-6px;top:.42rem;width:10px;height:10px;
  border-radius:50%;background:var(--orange);border:2px solid var(--paper)}
.timeline .when{font-family:var(--mono);font-size:.78rem;letter-spacing:.06em;color:var(--muted)}
.timeline h3{margin:.15rem 0 .1rem}
.timeline .org{color:var(--muted);font-size:.95rem;margin-bottom:.45rem}
.timeline p, .timeline ul{font-size:.98rem;color:#33475E}
.timeline ul{margin:.3rem 0 0 1.1rem}
.timeline ul li{border:none;padding:0 0 .3rem 0}
.timeline ul li::before{display:none}

/* Project / publication entries */
.entry{border-bottom:1px solid var(--line);padding:1.4rem 0}
.entry:last-child{border-bottom:none}
.entry .k{font-family:var(--mono);font-size:.72rem;letter-spacing:.12em;
  text-transform:uppercase;color:var(--cyan);display:block;margin-bottom:.35rem}
.entry h3{margin-bottom:.35rem}
.entry p{font-size:.99rem;color:#33475E}
.entry .meta{font-family:var(--mono);font-size:.78rem;color:var(--muted);margin-top:.35rem}

.publist{list-style:none}
.publist li{padding:.7rem 0;border-bottom:1px solid var(--line);max-width:var(--measure)}
.publist li:last-child{border-bottom:none}
.publist .venue{color:var(--muted);font-size:.92rem}

/* Buttons */
.btn{display:inline-block;font-family:var(--mono);font-size:.82rem;letter-spacing:.08em;
  text-transform:uppercase;padding:.65rem 1.1rem;border:1.5px solid var(--cyan);
  color:var(--cyan);margin-top:1rem}
.btn:hover{background:var(--cyan);color:#fff;text-decoration:none}
.btn.solid{background:var(--orange);border-color:var(--orange);color:#fff}
.btn.solid:hover{background:var(--orange-bright);border-color:var(--orange-bright)}

/* Footer */
footer{background:var(--deep);color:#9FB3C8;margin-top:4rem}
footer .inner{max-width:var(--wide);margin:0 auto;padding:2.2rem 1.25rem;
  display:flex;flex-wrap:wrap;gap:1rem 2.5rem;align-items:baseline}
footer a{color:var(--cyan-bright);font-family:var(--mono);font-size:.8rem}
footer .fine{font-size:.82rem;margin-left:auto}

@media (max-width:640px){
  .hero .inner{padding:3rem 1.1rem 4rem}
  section{padding:2.2rem 0 .6rem}
  footer .fine{margin-left:0}
}

/* Images */
.about-grid{display:grid;grid-template-columns:230px 1fr;gap:2rem;align-items:start}
.portrait{width:230px;height:230px;object-fit:cover;border:1px solid var(--line);
  border-bottom:3px solid var(--orange)}
.feature.has-thumb{display:grid;grid-template-columns:280px 1fr;gap:1.4rem;align-items:center}
.feature .thumb{width:100%;height:auto;border:1px solid #24405F}
@media (max-width:720px){
  .about-grid{grid-template-columns:1fr}
  .portrait{width:180px;height:180px}
  .feature.has-thumb{grid-template-columns:1fr}
}

/* Publication figures */
.pubfig{max-width:640px;width:100%;border:1px solid var(--line);margin:.8rem 0 .35rem;display:block}
.pubfig-cap{display:block;font-size:.85rem;color:var(--muted);max-width:640px}

/* Hero grid with portrait */
.hero-grid{display:grid;grid-template-columns:minmax(0,1fr) 340px;gap:3.5rem;align-items:center}
.hero-portrait{width:100%;height:auto;border:1px solid rgba(57,198,224,.4)}
@media (max-width:780px){
  .hero-grid{grid-template-columns:1fr}
  .hero-portrait{width:200px;order:-1}
}

/* Hero field line (below name) */
.hero .field{margin-top:.9rem;font-family:var(--serif);font-size:clamp(1.15rem,2.4vw,1.55rem);
  color:#C9D6E2;max-width:34ch;line-height:1.35}

/* Project figures */
.projfig{max-width:680px;width:100%;border:1px solid var(--line);margin:.9rem 0 .3rem;display:block}
.projfig.tall{max-width:340px}
.projfig-cap{display:block;font-family:var(--mono);font-size:.78rem;color:var(--muted);max-width:680px;margin-bottom:.2rem}
.figpair{display:grid;grid-template-columns:1fr 1fr;gap:.9rem;max-width:680px;margin:.9rem 0 .3rem}
.figpair img{border:1px solid var(--line);width:100%;height:auto;display:block;margin:0}
@media (max-width:560px){.figpair{grid-template-columns:1fr}}
.pagehead .btn{border-color:var(--cyan-bright);color:var(--cyan-bright);margin-top:1.2rem}
.pagehead .btn:hover{background:var(--cyan-bright);color:var(--deep)}

/* Click-to-zoom figures: link wraps image, opens full file */
a.zoom{display:inline-block;max-width:100%}
a.zoom img{cursor:zoom-in}
a.zoom:focus-visible{outline:2px solid var(--orange);outline-offset:3px}

/* Patent feature block */
.patent-grid{display:grid;grid-template-columns:1.15fr 1fr;gap:1.6rem;align-items:start;margin-top:.4rem}
@media(max-width:700px){.patent-grid{grid-template-columns:1fr}}
.patent-grid video{width:100%;border:1px solid var(--line);display:block;background:#000}

/* picture wrapper: neutral, image rules pass through */
picture{display:contents}
/* explicit safety where the image is a grid item: the picture takes the slot */
.hero-grid > picture{display:block;width:100%;min-width:0}
.hero-grid > picture > img{width:100%;height:auto}
.feature.has-thumb > picture{display:block;width:100%;min-width:0}
.feature.has-thumb > picture > .thumb{width:100%;height:auto}
@media (max-width:780px){
  .hero-grid > picture{width:200px;order:-1}
  .hero-grid > picture > img{width:100%}
}