/* ============================================================
   Rohan Gangakhedkar — "Aperture"
   Warm optical-instrument system. One stylesheet, no build.
   ============================================================ */

:root{
  /* Parchment. Warm paper ground, espresso ink, brass as accent. */
  --bg:         #F7F2E6;
  --surface:    #FFFDF6;
  --sunken:     #EBE3D2;
  --ink-strong: #171108;   /* display type */
  --text:       #1F1811;   /* body type    */
  --muted:      #5F5445;
  --muted-dim:  #756A59;   /* small mono labels — must clear 4.5:1 */
  --brass:      #7F6413;   /* 5.0:1 on the ground; brass that survives as text */
  --brass-deep: #5C470D;   /* hover deepens, it does not brighten */
  --on-brass:   #FFFBF0;   /* type sitting on a brass fill */
  --rule:       rgba(31,24,17,.13);
  --rule-mid:   rgba(31,24,17,.22);
  --rule-hi:    rgba(154,122,24,.50);

  --display: "Instrument Serif", Georgia, serif;
  --sans: Archivo, "Helvetica Neue", system-ui, sans-serif;
  --mono: "JetBrains Mono", ui-monospace, "SF Mono", Menlo, monospace;

  --shell: 1240px;
  --pad: 56px;
  --ease: cubic-bezier(.22,.75,.28,1);
}

*,*::before,*::after{box-sizing:border-box;margin:0;padding:0}

html{scroll-behavior:smooth}

body{
  background:var(--bg);
  color:var(--text);
  font-family:var(--sans);
  font-size:16px;
  line-height:1.6;
  -webkit-font-smoothing:antialiased;
  text-rendering:optimizeLegibility;
  overflow-x:hidden;
}

/* warm optical vignette, sits behind everything */
body::before{
  content:"";position:fixed;inset:0;z-index:-1;pointer-events:none;
  background:
    radial-gradient(74% 58% at 74% 10%, rgba(154,122,24,.10), transparent 66%),
    radial-gradient(60% 50% at 6% 88%, rgba(190,110,55,.06), transparent 72%);
}

img,video,canvas{max-width:100%;display:block}
a{color:inherit;text-decoration:none}

::selection{background:var(--brass);color:var(--on-brass)}

:focus-visible{outline:2px solid var(--brass);outline-offset:3px;border-radius:2px}

.shell{max-width:var(--shell);margin:0 auto;padding:0 var(--pad)}

/* ---------- type primitives ---------- */

.kicker{
  font:500 10px/1 var(--mono);
  letter-spacing:.2em;
  text-transform:uppercase;
  color:var(--brass);
}
.kicker--muted{color:var(--muted-dim)}

.display{
  font-family:var(--display);
  font-weight:400;
  letter-spacing:-.018em;
  line-height:1.04;
  color:var(--ink-strong);
}
.display em{font-style:italic;color:var(--brass)}

.lede{
  font-size:17px;line-height:1.68;color:var(--muted);
  max-width:52ch;
}

.rule{height:1px;background:var(--rule);border:0}

/* ---------- header ---------- */

.head{
  position:sticky;top:0;z-index:50;
  background:rgba(247,242,230,.88);
  backdrop-filter:blur(14px) saturate(1.3);
  -webkit-backdrop-filter:blur(14px) saturate(1.3);
  border-bottom:1px solid var(--rule);
}
.head__in{
  max-width:var(--shell);margin:0 auto;padding:16px var(--pad);
  display:flex;align-items:center;justify-content:space-between;gap:24px;
}
.head__name{
  font-family:var(--display);font-size:21px;letter-spacing:.005em;color:var(--ink-strong);
  white-space:nowrap;
}
.head__name span{color:var(--brass)}
.head__nav{display:flex;gap:28px;align-items:center}
.head__nav a{
  font:500 10.5px/1 var(--mono);letter-spacing:.16em;text-transform:uppercase;
  color:var(--muted);padding:6px 0;position:relative;transition:color .25s var(--ease);
}
.head__nav a::after{
  content:"";position:absolute;left:0;right:100%;bottom:0;height:1px;
  background:var(--brass);transition:right .35s var(--ease);
}
.head__nav a:hover{color:var(--text)}
.head__nav a:hover::after{right:0}
.head__nav a.is-cta{
  color:var(--brass);border:1px solid var(--rule-mid);
  padding:8px 14px;border-radius:2px;
}
.head__nav a.is-cta::after{display:none}
.head__nav a.is-cta:hover{background:var(--brass);color:var(--on-brass);border-color:var(--brass)}

/* ---------- hero ---------- */

.hero{padding:92px 0 84px;position:relative}
.hero__grid{
  display:grid;grid-template-columns:1fr 400px;gap:80px;align-items:center;
}
.hero__title{font-size:clamp(46px,5.4vw,74px);margin:26px 0 0}
.hero .lede{margin-top:26px}

.hero__cta{display:flex;gap:14px;margin-top:34px;flex-wrap:wrap}
.btn{
  display:inline-flex;align-items:center;gap:9px;
  font:500 10.5px/1 var(--mono);letter-spacing:.15em;text-transform:uppercase;
  padding:13px 20px;border:1px solid var(--rule-mid);border-radius:2px;
  color:var(--text);transition:all .28s var(--ease);
}
.btn:hover{border-color:var(--brass);color:var(--brass);transform:translateY(-1px)}
.btn--solid{background:var(--brass);border-color:var(--brass);color:var(--on-brass);font-weight:700}
.btn--solid:hover{background:var(--brass-deep);border-color:var(--brass-deep);color:var(--on-brass)}

/* ---------- the lens ---------- */

.lens{
  position:relative;width:400px;height:400px;
  display:grid;place-items:center;justify-self:end;
}
.lens__ring{position:absolute;border-radius:50%;border:1px solid var(--rule);pointer-events:none}
.lens__ring--1{inset:0}
.lens__ring--2{inset:36px;border-color:var(--rule-mid)}
.lens__ticks{
  position:absolute;inset:14px;border-radius:50%;pointer-events:none;
  background:repeating-conic-gradient(from 0deg,
    var(--brass) 0deg .4deg, transparent .4deg 6deg);
  -webkit-mask:radial-gradient(circle, transparent 0 47.5%, #000 47.5% 50%, transparent 50%);
          mask:radial-gradient(circle, transparent 0 47.5%, #000 47.5% 50%, transparent 50%);
  opacity:.55;
  animation:lensTurn 120s linear infinite;
}
@keyframes lensTurn{to{transform:rotate(360deg)}}

.lens__glass{
  position:relative;width:284px;height:284px;border-radius:50%;overflow:hidden;
  border:1px solid var(--brass);
  box-shadow:
    0 0 0 7px rgba(154,122,24,.09),
    0 24px 60px -22px rgba(60,44,18,.45),
    inset 0 0 44px rgba(0,0,0,.32);
  background:#111A20;
}
.lens__glass svg{width:100%;height:100%;display:block}
/* specular sweep across the glass */
.lens__glass::after{
  content:"";position:absolute;inset:0;border-radius:50%;pointer-events:none;
  background:linear-gradient(132deg, rgba(255,255,255,.20) 0%, rgba(255,255,255,.04) 30%, transparent 50%);
}

/* ---------- sections ---------- */

.sec{padding:88px 0}
.sec__head{
  display:flex;align-items:baseline;justify-content:space-between;gap:24px;
  border-bottom:1px solid var(--rule-mid);padding-bottom:16px;margin-bottom:44px;
}
.sec__title{font-family:var(--display);font-size:32px;letter-spacing:-.01em;color:var(--ink-strong)}
.sec__num{font:500 10px/1 var(--mono);letter-spacing:.2em;color:var(--brass)}

/* ---------- work entries ---------- */

.entry{
  display:grid;grid-template-columns:190px 1fr;gap:44px;
  padding:32px 0;border-bottom:1px solid var(--rule);
}
.entry:last-child{border-bottom:0}
.entry__when{padding-top:4px}
.entry__when b{
  display:block;font:600 12px/1.4 var(--sans);letter-spacing:.01em;color:var(--text);
}
.entry__when span{
  display:block;font:400 10px/1.5 var(--mono);letter-spacing:.1em;
  color:var(--muted-dim);text-transform:uppercase;margin-top:5px;
}
.entry__role{font-family:var(--display);font-size:25px;letter-spacing:-.005em;color:var(--ink-strong);margin-bottom:4px}
.entry__org{font:500 10px/1 var(--mono);letter-spacing:.16em;text-transform:uppercase;color:var(--brass);margin-bottom:16px}
.entry ul{list-style:none;display:grid;gap:11px}
.entry li{
  position:relative;padding-left:20px;font-size:14.5px;line-height:1.62;color:var(--muted);
}
.entry li::before{
  content:"";position:absolute;left:0;top:9px;width:7px;height:7px;
  border:1px solid var(--brass);border-radius:50%;
}
.entry li b{color:var(--text);font-weight:600}
.entry li .num{font-family:var(--mono);font-size:13px;font-weight:700;color:var(--brass)}

/* ---------- project grid ---------- */

.grid{display:grid;grid-template-columns:repeat(3,1fr);gap:34px 30px}

.pcard{display:block;position:relative;transition:transform .4s var(--ease)}
.pcard:hover{transform:translateY(-4px)}

.pcard__frame{
  position:relative;aspect-ratio:4/3;overflow:hidden;background:var(--sunken);
  border:1px solid var(--rule-mid);border-radius:2px;
  transition:border-color .35s var(--ease), box-shadow .35s var(--ease);
}
.pcard:hover .pcard__frame{
  border-color:var(--brass);
  box-shadow:0 16px 38px -22px rgba(60,44,18,.38), 0 0 0 1px rgba(154,122,24,.20);
}
.pcard__frame img,.pcard__frame video{
  position:absolute;inset:0;width:100%;height:100%;object-fit:cover;
}
.pcard__poster{
  filter:saturate(.94);
  transition:filter .45s var(--ease), transform .7s var(--ease);
}
.pcard:hover .pcard__poster{filter:saturate(1.02);transform:scale(1.03)}

/* the iris: motion irises open from the centre on hover */
.pcard__motion{
  opacity:0;
  clip-path:circle(0% at 50% 50%);
  transition:clip-path .68s var(--ease), opacity .32s linear;
}
.pcard.has-motion:hover .pcard__motion,
.pcard.has-motion:focus-visible .pcard__motion{
  opacity:1;clip-path:circle(82% at 50% 50%);
}
/* iris ring that expands with the reveal */
.pcard__iris{
  position:absolute;top:50%;left:50%;width:0;height:0;border-radius:50%;
  border:1px solid var(--brass);opacity:0;transform:translate(-50%,-50%);
  pointer-events:none;
}
.pcard.has-motion:hover .pcard__iris{
  animation:iris .78s var(--ease) forwards;
}
@keyframes iris{
  0%{width:0;height:0;opacity:.9}
  70%{opacity:.45}
  100%{width:135%;height:135%;opacity:0}
}

.pcard__tag{
  position:absolute;top:10px;left:10px;z-index:3;
  background:rgba(8,6,4,.82);backdrop-filter:blur(6px);
  border:1px solid var(--rule-mid);
  font:500 8.5px/1 var(--mono);letter-spacing:.14em;text-transform:uppercase;
  color:var(--brass);padding:6px 9px;border-radius:2px;
}
.pcard__body{padding:16px 2px 0}
.pcard__title{
  font-family:var(--display);font-size:20px;line-height:1.2;letter-spacing:-.005em;
  color:var(--ink-strong);transition:color .28s var(--ease);
}
.pcard:hover .pcard__title{color:var(--brass)}
.pcard__meta{
  display:flex;gap:10px;align-items:center;margin-top:9px;
  font:400 9.5px/1 var(--mono);letter-spacing:.11em;text-transform:uppercase;color:var(--muted-dim);
}
.pcard__meta i{font-style:normal;color:var(--rule-hi)}
.pcard__blurb{margin-top:11px;font-size:13.5px;line-height:1.58;color:var(--muted)}

/* ---------- about ---------- */

.about{display:grid;grid-template-columns:1.25fr 1fr;gap:70px;align-items:start}
.about .lede{font-size:16px}
.about p+p{margin-top:16px}

.spec{border-top:1px solid var(--rule)}
.spec__row{
  display:grid;grid-template-columns:118px 1fr;gap:18px;
  padding:13px 0;border-bottom:1px solid var(--rule);
}
.spec__row dt{
  font:500 9px/1.5 var(--mono);letter-spacing:.14em;text-transform:uppercase;color:var(--muted-dim);
}
.spec__row dd{font-size:13.5px;line-height:1.55;color:var(--text)}
.spec__row dd span{color:var(--muted)}

/* ---------- footer ---------- */

.foot{border-top:1px solid var(--rule-mid);padding:52px 0 60px;margin-top:40px}
.foot__in{display:flex;justify-content:space-between;align-items:flex-end;gap:40px;flex-wrap:wrap}
.foot__cta .display{font-size:38px}
.foot__links{display:flex;gap:22px;margin-top:22px;flex-wrap:wrap}
.foot__links a{
  font:500 10px/1 var(--mono);letter-spacing:.15em;text-transform:uppercase;color:var(--muted);
  border-bottom:1px solid var(--rule-mid);padding-bottom:4px;transition:all .28s var(--ease);
}
.foot__links a:hover{color:var(--brass);border-color:var(--brass)}
.foot__meta{
  font:400 9.5px/1.8 var(--mono);letter-spacing:.11em;text-transform:uppercase;
  color:var(--muted-dim);text-align:right;
}

/* ============================================================
   PROJECT PAGES
   ============================================================ */

.pcover{padding:76px 0 52px;border-bottom:1px solid var(--rule)}
.pcover__back{
  display:inline-flex;align-items:center;gap:9px;margin-bottom:34px;
  font:500 10px/1 var(--mono);letter-spacing:.16em;text-transform:uppercase;color:var(--muted);
  transition:color .25s var(--ease);
}
.pcover__back:hover{color:var(--brass)}
.pcover__title{font-size:clamp(34px,4.4vw,56px);max-width:19ch}
.pcover__course{
  font:500 10px/1.6 var(--mono);letter-spacing:.15em;text-transform:uppercase;
  color:var(--muted-dim);margin-top:20px;
}
.pcover__authors{margin-top:16px;font-size:14px;color:var(--muted)}
.pcover__authors a{color:var(--text);border-bottom:1px solid var(--rule-mid)}
.pcover__authors a:hover{color:var(--brass);border-color:var(--brass)}
.pcover__cta{display:flex;gap:12px;margin-top:30px;flex-wrap:wrap}

.pbody{max-width:820px;margin:0 auto;padding:60px 0 20px}
.pbody h2{
  font-family:var(--display);font-size:29px;letter-spacing:-.01em;color:var(--ink-strong);
  margin:56px 0 4px;padding-bottom:14px;border-bottom:1px solid var(--rule-mid);
}
.pbody h2:first-child{margin-top:0}
.pbody h3{
  font:600 15px/1.4 var(--sans);color:var(--text);margin:34px 0 10px;letter-spacing:-.005em;
}
.pbody p{margin:18px 0;font-size:15.5px;line-height:1.72;color:var(--muted)}
.pbody p b,.pbody strong{color:var(--text);font-weight:600}
.pbody a:not(.btn){color:var(--brass);border-bottom:1px solid var(--rule-mid)}
.pbody a:not(.btn):hover{border-color:var(--brass)}
.pbody ul,.pbody ol{margin:18px 0 18px 22px;color:var(--muted);font-size:15.5px;line-height:1.72}
.pbody li{margin:7px 0}

.tldr{
  border-left:2px solid var(--brass);padding:4px 0 4px 22px;margin:30px 0 38px;
}
.tldr span{
  display:block;font:700 9.5px/1 var(--mono);letter-spacing:.19em;
  text-transform:uppercase;color:var(--brass);margin-bottom:11px;
}
.tldr p{margin:0;font-size:16.5px;line-height:1.66;color:var(--text)}

/* figures — the lens motif, applied as a frame */
.fig{margin:38px 0}
.fig__media{
  border:1px solid var(--rule-mid);border-radius:2px;overflow:hidden;background:var(--sunken);
  position:relative;
}
.fig__media img,.fig__media video{
  display:block;margin:0 auto;
  max-width:100%;max-height:560px;width:auto;height:auto;
}
/* photos and screenshots earn the full column; plots do not */
.fig:not(.fig--plate) .fig__media img,
.fig:not(.fig--plate) .fig__media video{width:100%}
.fig figcaption{
  margin-top:12px;font:400 11px/1.65 var(--mono);letter-spacing:.06em;
  color:var(--muted-dim);text-align:center;
}
.fig figcaption b{color:var(--brass);font-weight:500}

.fig--row{display:grid;gap:16px}
.fig--2{grid-template-columns:1fr 1fr}
.fig--3{grid-template-columns:repeat(3,1fr)}
.fig--wide{max-width:none}

/* Plots and CAD renders arrive on white. On the parchment ground they get a
   raised white plate so the figure edge is defined rather than bleeding out. */
.fig--plate .fig__media{
  background:var(--surface);
  padding:16px 18px;
  border-color:var(--rule-mid);
  box-shadow:0 12px 30px -22px rgba(60,44,18,.4);
}
.fig--plate .fig--row{gap:0}
.fig--plate .fig--row .fig__media{
  border:0;padding:0;background:transparent;box-shadow:none;
}
.fig--plate .fig--row{
  background:var(--surface);padding:16px 18px;border:1px solid var(--rule-mid);
  border-radius:2px;box-shadow:0 12px 30px -22px rgba(60,44,18,.4);
  display:grid;gap:14px;
}

/* equations */
mjx-container{overflow-x:auto;overflow-y:hidden;max-width:100%}
.eq{margin:26px 0;color:var(--text)}

/* prev/next */
.pnav{border-top:1px solid var(--rule-mid);margin-top:70px;padding:40px 0 0;
  display:flex;justify-content:space-between;gap:24px;flex-wrap:wrap}
.pnav a{
  font:500 10px/1 var(--mono);letter-spacing:.15em;text-transform:uppercase;color:var(--muted);
  transition:color .25s var(--ease);
}
.pnav a:hover{color:var(--brass)}

/* ============================================================
   RESPONSIVE
   ============================================================ */

@media (max-width:1080px){
  :root{--pad:36px}
  .hero__grid{grid-template-columns:1fr 330px;gap:52px}
  .lens{width:330px;height:330px}
  .lens__glass{width:232px;height:232px}
  .grid{grid-template-columns:repeat(2,1fr)}
  .about{grid-template-columns:1fr;gap:44px}
}

@media (max-width:760px){
  :root{--pad:22px}
  body{font-size:15px}
  .head__in{padding:13px var(--pad)}
  .head__name{font-size:18px}
  .head__nav{gap:16px}
  .head__nav a{font-size:9.5px;letter-spacing:.12em}
  .head__nav a.is-cta{padding:7px 11px}

  .hero{padding:54px 0 48px}
  .hero__grid{grid-template-columns:1fr;gap:46px}
  .lens{justify-self:center;width:290px;height:290px}
  .lens__glass{width:206px;height:206px}
  .lens__ring--2{inset:28px}

  .sec{padding:58px 0}
  .sec__title{font-size:25px}
  .entry{grid-template-columns:1fr;gap:14px;padding:26px 0}
  .entry__role{font-size:21px}

  .grid{grid-template-columns:1fr;gap:28px}

  .foot__in{flex-direction:column;align-items:flex-start}
  .foot__cta .display{font-size:29px}
  .foot__meta{text-align:left}

  .pcover{padding:44px 0 36px}
  .pbody{padding:42px 0 10px}
  .pbody h2{font-size:24px;margin-top:42px}
  .fig--2,.fig--3{grid-template-columns:1fr}
}

@media (max-width:420px){
  .head__nav .is-hide-xs{display:none}
}

/* ============================================================
   MOTION / PRINT
   ============================================================ */

@media (prefers-reduced-motion:reduce){
  html{scroll-behavior:auto}
  *,*::before,*::after{
    animation-duration:.001ms!important;animation-iteration-count:1!important;
    transition-duration:.001ms!important;
  }
  .pcard.has-motion:hover .pcard__motion{clip-path:circle(82% at 50% 50%)}
  .lens__ticks{animation:none}
}

/* reveal-on-scroll (JS adds .is-in) */
.reveal{opacity:0;transform:translateY(16px);transition:opacity .7s var(--ease),transform .7s var(--ease)}
.reveal.is-in{opacity:1;transform:none}
@media (prefers-reduced-motion:reduce){.reveal{opacity:1;transform:none}}