/* ============================================================
   CVIG Lab — Computer Vision, Imaging & Graphics, IIT Gandhinagar
   Design: "The Sensor Array" — spectral sampling motif, cobalt accent,
   Space Grotesk / Inter / JetBrains Mono on cool graphite + soft paper.
   ============================================================ */

:root{
  --ink:#12141a;         /* sensor near-black */
  --ink-soft:#333844;
  --paper:#f6f6f3;       /* soft paper */
  --surface:#ffffff;
  --surface-2:#f0f0ea;
  --muted:#6b7180;
  --line:#e5e4dc;
  --line-strong:#d7d6cc;

  --accent:#2a52e0;      /* cobalt */
  --accent-deep:#1b3bb0;
  --accent-tint:#eaeefc;

  --v:#1e40af; --b:#2a52e0; --c:#4f74e8; --g:#3a63e4; --a:#6f8fe8; /* spectrum */

  --hero-bg:#0e1016;
  --hero-panel:#161923;
  --hero-ink:#f5f6f8;
  --hero-muted:#9aa1af;
  --hero-line:#262a36;

  --maxw:1140px;
  --radius:16px;
  --shadow:0 18px 48px -24px rgba(18,20,26,.35);
  --shadow-sm:0 6px 20px -14px rgba(18,20,26,.4);

  --f-display:"Space Grotesk",system-ui,sans-serif;
  --f-body:"Inter",system-ui,sans-serif;
  --f-mono:"JetBrains Mono",ui-monospace,monospace;
}

*{box-sizing:border-box}
html{scroll-behavior:smooth}
body{
  margin:0; background:var(--paper); color:var(--ink);
  font-family:var(--f-body); font-size:17px; line-height:1.6;
  -webkit-font-smoothing:antialiased; text-rendering:optimizeLegibility;
}
a{color:var(--accent); text-decoration:none}
a:hover{color:var(--accent-deep)}
img{max-width:100%; display:block}
.wrap{max-width:var(--maxw); margin:0 auto; padding:0 28px}
:focus-visible{outline:2.5px solid var(--accent); outline-offset:3px; border-radius:3px}

h1,h2,h3{font-family:var(--f-display); font-weight:600; letter-spacing:-.02em; line-height:1.08; margin:0}
.eyebrow{
  font-family:var(--f-mono); font-size:.72rem; letter-spacing:.18em; text-transform:uppercase;
  color:var(--accent); margin:0 0 14px;
}

/* ---------- nav ---------- */
.nav{position:sticky; top:0; z-index:50; background:rgba(246,246,243,.82);
  backdrop-filter:saturate(1.4) blur(12px); border-bottom:1px solid var(--line)}
.nav__inner{display:flex; align-items:center; justify-content:space-between; height:66px}
.brand{display:flex; align-items:center; gap:11px; font-family:var(--f-display);
  font-weight:600; letter-spacing:-.01em; color:var(--ink); font-size:1.06rem}
.brand:hover{color:var(--ink)}
.brand__mark{width:26px; height:26px; border-radius:7px; display:block; flex:0 0 auto}
.brand__sub{font-family:var(--f-mono); font-size:.62rem; letter-spacing:.14em; text-transform:uppercase;
  color:var(--muted); border-left:1px solid var(--line-strong); padding-left:11px; margin-left:2px}
.nav-links{display:flex; align-items:center; gap:30px}
.nav-links a{font-size:.9rem; color:var(--ink-soft); font-weight:500}
.nav-links a:hover{color:var(--accent)}
.nav-links a.nav-cta{color:var(--accent); font-weight:600}
.nav-toggle,.nav-burger{display:none}

/* ---------- hero ---------- */
.hero{background:var(--hero-bg); color:var(--hero-ink); position:relative; overflow:hidden}
.hero__grid{display:grid; grid-template-columns:1.05fr .95fr; gap:40px; align-items:center;
  padding:92px 0 84px}
.hero__eyebrow{color:#aeb7ff}
.hero h1{font-size:clamp(2.5rem,6vw,4.15rem); color:var(--hero-ink); font-weight:600}
.hero h1 .amp{font-weight:400; font-style:italic; letter-spacing:0}
.hero__lede{font-size:1.16rem; color:var(--hero-muted); margin:22px 0 8px; max-width:40ch; line-height:1.55}
.hero__pi{font-family:var(--f-mono); font-size:.82rem; color:var(--hero-muted); margin:26px 0 0;
  padding-top:20px; border-top:1px solid var(--hero-line)}
.hero__pi strong{color:var(--hero-ink); font-weight:600}
.hero__actions{display:flex; flex-wrap:wrap; gap:14px; margin-top:30px}
.hero__figure{position:relative}
.hero__figure svg{width:100%; height:auto; display:block}
.hero__cap{position:absolute; bottom:6px; left:2px; font-family:var(--f-mono); font-size:.62rem;
  letter-spacing:.12em; text-transform:uppercase; color:var(--hero-muted)}

.btn{display:inline-flex; align-items:center; gap:9px; font-family:var(--f-body); font-weight:600;
  font-size:.92rem; padding:13px 22px; border-radius:11px; border:1px solid transparent;
  transition:transform .15s ease, background .15s ease, border-color .15s ease}
.btn svg{width:16px; height:16px}
.btn--primary{background:var(--accent); color:#fff}
.btn--primary:hover{background:#3a61ef; color:#fff; transform:translateY(-2px)}
.btn--ghost{background:transparent; color:var(--hero-ink); border-color:var(--hero-line)}
.btn--ghost:hover{border-color:#4b5468; color:var(--hero-ink); transform:translateY(-2px)}
.btn--dark{background:var(--ink); color:#fff}
.btn--dark:hover{background:#23262f; color:#fff; transform:translateY(-2px)}

/* ---------- stats ---------- */
.stats{background:var(--ink); color:#fff}
.stats__grid{display:grid; grid-template-columns:repeat(4,1fr)}
.stat{padding:30px 24px; border-left:1px solid #23262f}
.stat:first-child{border-left:none}
.stat__num{font-family:var(--f-display); font-size:2rem; font-weight:600; letter-spacing:-.02em}
.stat__num .u{color:var(--accent); font-size:1.2rem; vertical-align:super; margin-left:1px}
.stat__label{font-family:var(--f-mono); font-size:.68rem; letter-spacing:.1em; text-transform:uppercase;
  color:#9aa1af; margin-top:7px}

/* ---------- section scaffolding ---------- */
.section{padding:88px 0}
.section--tint{background:var(--surface)}
.section-head{max-width:64ch; margin-bottom:44px}
.section-head h2{font-size:clamp(1.8rem,3.4vw,2.5rem)}
.section-head p{color:var(--muted); font-size:1.08rem; margin:16px 0 0}

/* ---------- about ---------- */
.about__grid{display:grid; grid-template-columns:1.4fr 1fr; gap:48px; align-items:start}
.about__body p{margin:0 0 18px; font-size:1.12rem}
.about__body p:last-child{margin-bottom:0}
.pi-card{background:var(--surface); border:1px solid var(--line); border-radius:var(--radius);
  padding:26px; box-shadow:var(--shadow-sm)}
.pi-card__top{display:flex; align-items:center; gap:16px}
.avatar{width:56px; height:56px; border-radius:14px; flex:0 0 auto; display:grid; place-items:center;
  font-family:var(--f-display); font-weight:600; color:#fff; font-size:1.2rem;
  background:linear-gradient(135deg,var(--v),var(--b) 55%,var(--c))}
.pi-card__name{font-family:var(--f-display); font-weight:600; font-size:1.14rem}
.pi-card__role{font-size:.86rem; color:var(--muted)}
.pi-card__list{list-style:none; padding:0; margin:20px 0 0; display:grid; gap:9px}
.pi-card__list li{font-size:.9rem; color:var(--ink-soft); display:flex; gap:10px}
.pi-card__list li::before{content:""; width:7px; height:7px; border-radius:50%; margin-top:7px;
  background:var(--accent); flex:0 0 auto}
.pi-card__links{margin-top:20px; padding-top:18px; border-top:1px solid var(--line); display:flex; gap:18px;
  font-family:var(--f-mono); font-size:.78rem}

/* ---------- research areas ---------- */
.area-grid{display:grid; grid-template-columns:repeat(3,1fr); gap:22px}
.area{background:var(--surface); border:1px solid var(--line); border-radius:var(--radius);
  padding:26px 24px; transition:transform .18s ease, box-shadow .18s ease, border-color .18s ease}
.area:hover{transform:translateY(-4px); box-shadow:var(--shadow); border-color:var(--line-strong)}
.area__dot{width:13px; height:13px; border-radius:50%; display:block; margin-bottom:18px}
.area__idx{font-family:var(--f-mono); font-size:.68rem; color:var(--muted); float:right; letter-spacing:.08em}
.area h3{font-size:1.16rem; margin-bottom:10px; letter-spacing:-.01em}
.area p{font-size:.96rem; color:var(--muted); margin:0}

/* ---------- publications ---------- */
.pub-list{border-top:1px solid var(--line)}
.pub{display:grid; grid-template-columns:150px 1fr auto; gap:24px; align-items:baseline;
  padding:22px 4px; border-bottom:1px solid var(--line); transition:background .15s ease}
.pub:hover{background:var(--surface)}
.pub__venue{font-family:var(--f-mono); font-size:.72rem; letter-spacing:.04em}
.pub__venue b{display:block; color:var(--ink); font-weight:700}
.pub__venue span{color:var(--muted)}
.pub__title{font-family:var(--f-display); font-weight:600; font-size:1.08rem; letter-spacing:-.01em; line-height:1.3}
.pub__title a{color:var(--ink)}
.pub__title a:hover{color:var(--accent)}
.pub__authors{color:var(--muted); font-size:.9rem; margin-top:4px}
.pub__link{font-family:var(--f-mono); font-size:.74rem; white-space:nowrap; color:var(--accent)}
.pub-more{margin-top:32px; display:flex; gap:16px; flex-wrap:wrap; align-items:center}

/* ---------- people ---------- */
.people__pi{display:flex; gap:18px; align-items:center; background:var(--surface); border:1px solid var(--line);
  border-radius:var(--radius); padding:22px 24px; margin-bottom:34px; box-shadow:var(--shadow-sm)}
.people__pi .avatar{width:60px; height:60px; font-size:1.3rem}
.people__pi h3{font-size:1.2rem}
.people__pi p{margin:4px 0 0; color:var(--muted); font-size:.92rem}
.subhead{font-family:var(--f-mono); font-size:.72rem; letter-spacing:.14em; text-transform:uppercase;
  color:var(--muted); margin:0 0 20px}
.member-grid{display:grid; grid-template-columns:repeat(5,1fr); gap:18px 16px; margin-bottom:42px}
.member{display:flex; flex-direction:column; align-items:center; text-align:center; gap:11px}
.member .avatar{width:52px; height:52px; border-radius:50%; font-size:1.02rem;
  background:linear-gradient(135deg,#2a52e0,#4f74e8)}
.member:nth-child(3n) .avatar{background:linear-gradient(135deg,#1e40af,#2a52e0)}
.member:nth-child(3n+1) .avatar{background:linear-gradient(135deg,#3a63e4,#4f74e8)}
.member span{font-size:.86rem; font-weight:500; color:var(--ink-soft); line-height:1.25}
.alum-list{display:grid; grid-template-columns:repeat(3,1fr); gap:20px}
.alum{background:var(--surface); border:1px solid var(--line); border-radius:14px; padding:20px}
.alum__year{font-family:var(--f-mono); font-size:.72rem; color:var(--accent); letter-spacing:.06em}
.alum__name{font-family:var(--f-display); font-weight:600; font-size:1.04rem; margin:6px 0 6px}
.alum__note{font-size:.88rem; color:var(--muted); margin:0}

/* ---------- news ---------- */
.news-list{display:grid; gap:0}
.news{display:grid; grid-template-columns:120px 1fr; gap:24px; padding:20px 0; border-top:1px solid var(--line)}
.news:last-child{border-bottom:1px solid var(--line)}
.news__date{font-family:var(--f-mono); font-size:.78rem; color:var(--accent); letter-spacing:.04em; padding-top:2px}
.news__body{font-size:1rem; color:var(--ink-soft)}
.news__body em{color:var(--ink); font-style:italic}

/* ---------- teaching ---------- */
.teach{display:grid; grid-template-columns:auto 1fr auto; gap:26px; align-items:center;
  background:var(--surface); border:1px solid var(--line); border-radius:var(--radius);
  padding:28px 30px; box-shadow:var(--shadow-sm)}
.teach__code{font-family:var(--f-mono); font-size:.9rem; font-weight:600; color:#fff; background:var(--ink);
  padding:10px 14px; border-radius:10px; letter-spacing:.04em}
.teach h3{font-size:1.24rem}
.teach p{margin:6px 0 0; color:var(--muted); font-size:.95rem}

/* ---------- join / contact ---------- */
.join{background:var(--hero-bg); color:var(--hero-ink)}
.join__grid{display:grid; grid-template-columns:1.3fr 1fr; gap:52px; align-items:start; padding:80px 0}
.join h2{font-size:clamp(1.9rem,3.6vw,2.6rem); color:var(--hero-ink)}
.join p{color:var(--hero-muted); font-size:1.1rem; margin:18px 0 26px; max-width:46ch}
.join .eyebrow{color:#aeb7ff}
.contact{font-style:normal; border-left:1px solid var(--hero-line); padding-left:30px}
.contact dt{font-family:var(--f-mono); font-size:.68rem; letter-spacing:.12em; text-transform:uppercase;
  color:var(--hero-muted); margin-top:18px}
.contact dt:first-child{margin-top:0}
.contact dd{margin:5px 0 0; color:var(--hero-ink); font-size:.98rem; line-height:1.5}
.contact a{color:#aeb7ff}

/* ---------- footer ---------- */
.footer{background:#0a0b0f; color:#8b91a0; padding:30px 0}
.footer__inner{display:flex; justify-content:space-between; flex-wrap:wrap; gap:14px;
  font-size:.84rem; font-family:var(--f-mono); letter-spacing:.02em}
.footer a{color:#aeb7ff}

/* ---------- motion / a11y ---------- */
@keyframes rise{from{opacity:0; transform:translateY(16px)} to{opacity:1; transform:none}}
.hero__intro>*{animation:rise .7s cubic-bezier(.2,.7,.2,1) both}
.hero__intro>*:nth-child(2){animation-delay:.06s}
.hero__intro>*:nth-child(3){animation-delay:.12s}
.hero__intro>*:nth-child(4){animation-delay:.18s}
.hero__intro>*:nth-child(5){animation-delay:.24s}
@media (prefers-reduced-motion:reduce){
  html{scroll-behavior:auto}
  *{animation:none!important; transition:none!important}
}

/* ---------- responsive ---------- */
@media (max-width:900px){
  .hero__grid{grid-template-columns:1fr; gap:8px; padding:64px 0 56px}
  .hero__figure{order:-1; max-width:420px}
  .about__grid{grid-template-columns:1fr; gap:32px}
  .area-grid{grid-template-columns:repeat(2,1fr)}
  .stats__grid{grid-template-columns:repeat(2,1fr)}
  .stat:nth-child(3){border-left:none}
  .stat:nth-child(3),.stat:nth-child(4){border-top:1px solid #23262f}
  .member-grid{grid-template-columns:repeat(4,1fr)}
  .alum-list{grid-template-columns:1fr}
  .join__grid{grid-template-columns:1fr; gap:32px}
  .contact{border-left:none; border-top:1px solid var(--hero-line); padding-left:0; padding-top:24px}
}
@media (max-width:820px){
  .nav-burger{display:flex; flex-direction:column; gap:5px; width:30px; height:30px; justify-content:center;
    cursor:pointer; z-index:60}
  .nav-burger span{height:2px; background:var(--ink); border-radius:2px; transition:transform .2s, opacity .2s}
  .nav-toggle:checked ~ .nav-burger span:nth-child(1){transform:translateY(7px) rotate(45deg)}
  .nav-toggle:checked ~ .nav-burger span:nth-child(2){opacity:0}
  .nav-toggle:checked ~ .nav-burger span:nth-child(3){transform:translateY(-7px) rotate(-45deg)}
  .nav-links{position:fixed; inset:66px 0 auto 0; flex-direction:column; align-items:flex-start; gap:0;
    background:var(--surface); border-bottom:1px solid var(--line); padding:8px 28px 20px;
    transform:translateY(-120%); transition:transform .28s ease; box-shadow:var(--shadow)}
  .nav-links a{width:100%; padding:13px 0; border-bottom:1px solid var(--line); font-size:1rem}
  .nav-toggle:checked ~ .nav-links{transform:none}
}
@media (max-width:560px){
  body{font-size:16px}
  .wrap{padding:0 20px}
  .section{padding:60px 0}
  .area-grid{grid-template-columns:1fr}
  .stats__grid{grid-template-columns:1fr}
  .stat{border-left:none; border-top:1px solid #23262f}
  .stat:first-child{border-top:none}
  .pub{grid-template-columns:1fr; gap:6px}
  .pub__link{margin-top:6px}
  .member-grid{grid-template-columns:repeat(3,1fr)}
  .news{grid-template-columns:1fr; gap:4px}
  .teach{grid-template-columns:1fr; text-align:left; gap:16px}
}

/* area spectral dots */
.area:nth-child(1) .area__dot{background:#1e3a8a}
.area:nth-child(2) .area__dot{background:#2547c8}
.area:nth-child(3) .area__dot{background:#2a52e0}
.area:nth-child(4) .area__dot{background:#4a6fe6}
.area:nth-child(5) .area__dot{background:#6f8fe8}
.area:nth-child(6) .area__dot{background:#9db6f2}
.pub-note{font-family:var(--f-mono); font-size:.78rem; color:var(--muted)}

/* ---------- sub-page hero ---------- */
.page-hero{background:var(--hero-bg); color:var(--hero-ink); padding:60px 0 50px}
.page-hero .eyebrow{color:#aeb7ff}
.page-hero h1{font-size:clamp(2rem,4.6vw,3rem); color:var(--hero-ink)}
.page-hero p{color:var(--hero-muted); max-width:62ch; margin:16px 0 0; font-size:1.1rem}
.page-hero .hero__actions{margin-top:26px}

/* ---------- team page ---------- */
.team-grid{display:grid; grid-template-columns:repeat(4,1fr); gap:22px}
.tcard{text-align:center; background:var(--surface); border:1px solid var(--line); border-radius:16px;
  padding:26px 16px; transition:transform .16s ease, box-shadow .16s ease}
.tcard:hover{transform:translateY(-3px); box-shadow:var(--shadow-sm)}
.tcard .avatar{width:64px; height:64px; border-radius:50%; margin:0 auto 14px; font-size:1.22rem;
  background:linear-gradient(135deg,#2a52e0,#4f74e8)}
.tcard:nth-child(3n) .avatar{background:linear-gradient(135deg,#1e40af,#2a52e0)}
.tcard:nth-child(3n+1) .avatar{background:linear-gradient(135deg,#3a63e4,#4f74e8)}
.tcard__name{font-family:var(--f-display); font-weight:600; font-size:1rem; letter-spacing:-.01em}
.tcard__focus{font-size:.82rem; color:var(--muted); margin-top:5px; line-height:1.4}
.tcard__tag{display:inline-block; margin-top:11px; font-family:var(--f-mono); font-size:.6rem;
  letter-spacing:.09em; text-transform:uppercase; color:var(--accent); background:var(--accent-tint);
  padding:4px 10px; border-radius:20px}

/* ---------- publications page ---------- */
.year-block{margin-bottom:10px}
.year-head{font-family:var(--f-display); font-weight:600; font-size:1.5rem; letter-spacing:-.02em;
  padding:26px 0 4px; color:var(--ink)}
.pat-h{font-size:clamp(1.6rem,3vw,2rem); margin:52px 0 6px; padding-top:34px; border-top:1px solid var(--line)}

@media (max-width:900px){ .gallery{grid-template-columns:repeat(2,1fr)} .team-grid{grid-template-columns:repeat(3,1fr)} }
@media (max-width:560px){ .gallery{grid-template-columns:1fr} .team-grid{grid-template-columns:repeat(2,1fr)} }

.section .subhead + .team-grid{margin-bottom:6px}
.team-grid ~ .subhead{margin-top:40px}
.team-grid + .pub-note{margin-top:22px}