/* ==========================================================================
   Arnav Agrawal . personal site
   Light "paper" only, by design. Nothing below the token block references a literal colour.
   ========================================================================== */

:root{
  --bg:#FBFAF7;
  --surface:rgba(30,36,52,.035);
  --text:#3A3D45;
  --strong:#14161B;
  --muted:#737885;
  --rule:#E3E1DA;
  --rule-soft:rgba(30,36,52,.07);
  --accent:#3550C4;
  --accent-soft:rgba(53,80,196,.08);
  --live:#2F9E63;
  --todo:#B8652A;
  --nav-bg:rgba(251,250,247,.82);
  --chip-bg:transparent;
  --dom-math:#3550C4; --dom-cs:#23855A; --dom-fin:#B06A2C;

  /* figure palette */
  --viz-frame:rgba(40,48,72,.26);
  --viz-node:rgba(40,48,72,.40);
  --viz-edge:rgba(40,48,72,.16);
  --viz-live:53,80,196;
  --viz-spark:28,46,140;
  --viz-label:rgba(40,48,72,.50);
  --viz-ablate:196,72,60;
}

:root{
  --serif:"Source Serif 4",Georgia,"Times New Roman",serif;
  --mono:"IBM Plex Mono",ui-monospace,Menlo,monospace;
  --gutter:clamp(20px,4.5vw,40px);
  --col:680px;          /* reading measure */
  --nav-h:56px;
}

/* --------------------------------------------------------------- reset -- */

*,*::before,*::after{box-sizing:border-box}
html{overflow-x:clip;scroll-behavior:smooth;scroll-padding-top:calc(var(--nav-h) + 24px);-webkit-text-size-adjust:100%}
@media (prefers-reduced-motion:reduce){html{scroll-behavior:auto}}

body{
  margin:0;
  background:var(--bg);
  color:var(--text);
  font:400 16px/1.68 var(--serif);
  font-variant-numeric:oldstyle-nums proportional-nums;
  -webkit-font-smoothing:antialiased;
  -moz-osx-font-smoothing:grayscale;
  transition:background .4s ease,color .4s ease;
}
a{color:inherit}
:focus-visible{outline:2px solid var(--accent);outline-offset:3px;border-radius:3px}
::selection{background:var(--accent-soft);color:var(--strong)}
.todo{color:var(--todo);font-style:italic}

/* ------------------------------------------------------------------ nav -- */

nav.tabs{
  position:sticky;top:0;z-index:20;
  height:var(--nav-h);
  background:var(--nav-bg);
  -webkit-backdrop-filter:saturate(180%) blur(14px);
  backdrop-filter:saturate(180%) blur(14px);
  border-bottom:1px solid var(--rule-soft);
}
nav.tabs .in{
  height:100%;
  max-width:calc(var(--col) + 2 * var(--gutter));margin:0 auto;padding:0 var(--gutter);
  display:flex;align-items:center;gap:18px;
}
nav.tabs .me{
  font:500 13px/1 var(--mono);letter-spacing:.01em;
  color:var(--strong);text-decoration:none;flex:none;
}
nav.tabs ul{
  list-style:none;display:flex;align-items:center;gap:2px;
  margin:0;padding:0;overflow-x:auto;
  min-width:0;flex:1 1 auto;
  scrollbar-width:none;-ms-overflow-style:none;
}
nav.tabs ul::-webkit-scrollbar{display:none}
a.t{
  display:block;white-space:nowrap;text-decoration:none;
  font:400 12px/1 var(--mono);letter-spacing:.02em;
  color:var(--muted);padding:7px 10px;border-radius:999px;
  transition:color .18s ease,background .18s ease;
}
a.t:hover{color:var(--strong)}
a.t.on{color:var(--accent);background:var(--accent-soft)}

/* --------------------------------------------------------------- layout -- */

.wrap{max-width:calc(var(--col) + 2 * var(--gutter));margin:0 auto;padding:44px var(--gutter) 64px}

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

.status{
  display:flex;align-items:center;gap:10px;
  font:400 12px/1.6 var(--mono);color:var(--muted);
  margin-bottom:24px;
}
.dot{width:6px;height:6px;border-radius:50%;background:var(--live);flex:none}
h1{
  font:600 clamp(38px,5.6vw,50px)/1.05 var(--serif);
  letter-spacing:-.025em;margin:0;color:var(--strong);
}
h1 span{color:var(--muted);font-weight:400}
.tagline{margin:14px 0 0;font-size:18px;line-height:1.5;color:var(--text)}

.links{margin-top:22px;display:flex;flex-wrap:wrap;gap:8px}
.links a{
  font:400 12px/1 var(--mono);text-decoration:none;color:var(--text);
  padding:8px 13px;border:1px solid var(--rule);border-radius:999px;
  transition:color .18s ease,border-color .18s ease,background .18s ease,transform .18s ease;
}
.links a:hover{color:var(--strong);border-color:var(--muted);background:var(--surface);transform:translateY(-1px)}
.reach{align-self:center;margin-left:6px;font:400 12px/1 var(--mono);color:var(--muted)}
.reach .addr{color:var(--text);user-select:all}

/* --------------------------------------------------------------- figure -- */

.fig{margin:40px 0 0}
.fig-stage{position:relative}
#field{
  display:block;width:100%;
  height:clamp(360px,60vw,480px);
  border:1px solid var(--rule);border-radius:10px;
  background:var(--surface);
  cursor:grab;touch-action:pan-y;              /* vertical page scroll still works */
  -webkit-user-select:none;user-select:none;
}

.fig figcaption{
  margin-top:10px;
  font-size:13.5px;line-height:1.55;color:var(--muted);
}
.fig figcaption b{color:var(--strong);font-weight:600}

/* explanation panel, floating in the figure's top-right corner */
.explain{
  position:absolute;top:14px;right:14px;width:236px;
  padding:13px 14px 12px;border:1px solid var(--rule);border-radius:8px;
  background:rgba(251,250,247,.92);
  -webkit-backdrop-filter:blur(6px);backdrop-filter:blur(6px);
}
.explain.swap{animation:rise .3s ease both}
@media (prefers-reduced-motion:reduce){.explain.swap{animation:none}}
.ex-k{font:500 9.5px/1.4 var(--mono);letter-spacing:.1em;text-transform:uppercase;color:var(--accent)}
.explain h4{margin:6px 0 6px;font:600 15.5px/1.3 var(--serif);color:var(--strong)}
.explain p{margin:0;font-size:13px;line-height:1.55;color:var(--text)}
.ex-ref{margin-top:9px;font:400 9.5px/1.45 var(--mono);color:var(--muted)}
#ex-close{
  margin-top:10px;cursor:pointer;font:400 10px/1 var(--mono);color:var(--accent);
  background:var(--accent-soft);border:0;border-radius:999px;padding:6px 10px;
}

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

.intro{display:grid;gap:15px}
.intro .lead{color:var(--strong);font-weight:600}
.intro p{margin:0}
.intro em{
  font-style:normal;color:var(--strong);
  box-shadow:inset 0 -1px 0 0 var(--rule);
}

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

section.s{margin-top:72px;scroll-margin-top:calc(var(--nav-h) + 28px)}
section.s[aria-label="About"]{margin-top:44px}
h2{
  font:500 10px/1 var(--mono);color:var(--muted);
  letter-spacing:.14em;text-transform:uppercase;
  margin:0 0 20px;display:flex;align-items:center;gap:14px;
}
h2::after{content:"";flex:1;height:1px;background:var(--rule)}

/* ---------------------------------------------- research + experience -- */

.experience-list{border-top:1px solid var(--rule)}
.experience-entry{border-bottom:1px solid var(--rule)}
.experience-item{
  position:relative;
  display:grid;grid-template-columns:34px 1fr auto;column-gap:16px;row-gap:3px;
  align-items:center;text-align:left;
  font:400 15px/1.45 var(--serif);color:var(--text);
  background:transparent;border:0;padding:16px 10px;
  margin:0 -10px;width:calc(100% + 20px);
  cursor:pointer;border-radius:8px;
  transition:background .18s ease,transform .18s ease;
}
.experience-item:hover,.experience-item:focus-visible{background:var(--surface);transform:translateX(3px)}
.experience-item.active{background:var(--surface)}

.company-logo{grid-row:span 2;align-self:start;margin-top:2px;width:34px;height:34px;display:grid;place-items:center;border-radius:7px;overflow:hidden;border:1px solid var(--rule-soft);transition:transform .18s ease}
.company-logo img{display:block;width:30px;height:30px;object-fit:contain}
.experience-item:hover .company-logo{transform:scale(1.1)}
.company-logo.chip{background:var(--chip-bg);padding:2px}
.company-logo.chip img{width:28px;height:28px}

.company-line{display:flex;align-items:baseline;flex-wrap:wrap;min-width:0}
.experience-item strong{color:var(--strong);font-weight:600;font-size:16px}
.exp-sum{grid-column:2 / -1;font-size:14px;line-height:1.5;color:var(--text)}
.experience-item small{font-size:14px;color:var(--muted)}
.experience-item small::before{content:" / ";color:var(--rule);white-space:pre}
.tag{
  margin-left:10px;align-self:center;
  font:500 9px/1 var(--mono);font-style:normal;letter-spacing:.12em;text-transform:uppercase;
  color:var(--accent);padding:4px 6px;border-radius:4px;
  background:color-mix(in srgb,currentColor 11%,transparent);
}
.tag.research{color:var(--accent)}
.tag.engineering{color:var(--dom-cs)}
.tag.teaching{color:var(--dom-fin)}
.experience-item time{font:400 12px/1 var(--mono);color:var(--muted);white-space:nowrap}

.experience-detail{
  display:none;
  padding:4px 0 22px 40px;
  border-left:1px solid var(--accent);margin-left:10px;
}
.experience-detail.visible{display:block;animation:rise .28s ease both}
@keyframes rise{from{opacity:0;transform:translateY(-4px)}to{opacity:1;transform:none}}
@media (prefers-reduced-motion:reduce){.experience-detail.visible{animation:none}}
.detail-kicker{font:400 10px/1.4 var(--mono);text-transform:uppercase;letter-spacing:.1em;color:var(--accent)}
.experience-detail h3{font:600 19px/1.25 var(--serif);color:var(--strong);margin:9px 0 11px}
.experience-detail p,.experience-detail #experience-copy{margin:0}
.experience-metrics{display:flex;flex-wrap:wrap;gap:7px;margin-top:16px}
.experience-metrics span{
  font:400 10.5px/1 var(--mono);color:var(--accent);
  background:var(--accent-soft);padding:6px 9px;border-radius:999px;
}

/* -------------------------------------------------------------- papers -- */

/* projects read like a publication list: thumbnail, title, authors, venue, abstract.
   Thumbnails come from very different sources, so they rest desaturated and take
   their colour on hover; that keeps the column calm. */
.papers{display:grid;border-top:1px solid var(--rule)}
.paper{
  display:grid;grid-template-columns:150px minmax(0,1fr);gap:20px;align-items:start;
  padding:20px 0;border-bottom:1px solid var(--rule);
}
.thumb{
  aspect-ratio:3/2;border:1px solid var(--rule);border-radius:6px;overflow:hidden;
  background:#fff;display:grid;place-items:center;
}
.thumb img{
  width:100%;height:100%;object-fit:contain;
  filter:grayscale(1) contrast(.92);opacity:.72;
  transition:filter .35s ease,opacity .35s ease,transform .35s ease;
}
.paper:hover .thumb img{filter:none;opacity:1;transform:scale(1.03)}
/* a dark image only loses its accent colours at rest; fading it would turn the black grey */
.thumb.dark{background:#07080A;border-color:#07080A}
.thumb.dark img{opacity:1;object-fit:cover}
.paper h3{margin:0;font:600 16px/1.35 var(--serif);color:var(--strong);text-wrap:pretty}
.authors{margin-top:6px;font-size:13.5px;line-height:1.45;color:var(--text)}
.authors b{font-weight:600;color:var(--strong)}
.authors span{color:var(--muted);font-size:12.5px}
.venue{margin-top:3px;font:400 11px/1.5 var(--mono);color:var(--muted);letter-spacing:.02em}
.paper p{margin:9px 0 0;font-size:14px;line-height:1.6;color:var(--text)}

/* ------------------------------------------------------------- writing -- */

.writing-note{margin:0;font-size:15px;line-height:1.65;color:var(--text)}
.writing-note + .writing-note{margin-top:12px}

.posts{list-style:none;margin:0;padding:0;border-top:1px solid var(--rule)}
.posts a{
  display:flex;justify-content:space-between;gap:16px;align-items:baseline;
  padding:12px 0;border-bottom:1px solid var(--rule);text-decoration:none;
}
.post-t{color:var(--strong)}
.posts a:hover .post-t{color:var(--accent)}
.posts time{font:400 12px/1 var(--mono);color:var(--muted)}

/* ------------------------------------------------------------ education -- */

.school{display:flex;justify-content:space-between;gap:16px;align-items:baseline}
.school > div:first-child{flex:1;min-width:0}
.org{color:var(--strong);font-weight:600}
.role{color:var(--muted);font-size:14.5px;margin-top:2px}
.thesis{margin-top:8px;font-size:14.5px;line-height:1.55;color:var(--text)}
.thesis b{color:var(--strong);font-weight:600}
.date{font:400 12px/1 var(--mono);color:var(--muted);white-space:nowrap}

.cw-head{
  display:flex;justify-content:space-between;gap:12px;flex-wrap:wrap;
  margin:34px 0 14px;font:400 10px/1 var(--mono);
  letter-spacing:.12em;text-transform:uppercase;color:var(--muted);
}
.cw-list{
  margin:18px 0 0;display:grid;gap:24px 30px;
  grid-template-columns:1fr 1fr;              /* pure maths left, ml / cs right */
  align-items:start;
}
.cw-col{display:grid;gap:24px;align-content:start}
.cw-group h3{
  margin:0 0 8px;display:flex;align-items:center;gap:8px;
  font:500 10px/1 var(--mono);letter-spacing:.12em;text-transform:uppercase;
}
.cw-group h3::before{content:"";width:6px;height:6px;border-radius:50%;background:currentColor;flex:none}
.cw-group h3 em{font-style:normal;color:var(--muted);font-weight:400;letter-spacing:.06em}
.cw-group.math h3{color:var(--dom-math)}
.cw-group.cs h3{color:var(--dom-cs)}
.cw-group h3{letter-spacing:.07em;white-space:nowrap}
.cw-group.finance h3{color:var(--dom-fin)}

.cw-rows{list-style:none;margin:0;padding:0}
.cw-row{
  display:grid;grid-template-columns:70px 1fr;gap:10px;align-items:baseline;
  padding:6px 7px;margin:0 -7px;border-radius:6px;
  border-bottom:1px solid var(--rule-soft);
}
.cw-row:last-child{border-bottom:0}
.cw-code{font:400 10px/1.7 var(--mono);color:var(--muted);white-space:nowrap}
.cw-row.grad .cw-code{color:var(--text)}
.cw-name{font-size:13.5px;line-height:1.45;color:var(--text)}
.cw-star{font-style:normal;color:var(--accent);margin-left:3px}
.cw-note{margin:18px 0 0;font:400 11px/1.5 var(--mono);color:var(--muted)}

/* ------------------------------------------------------------ otherwise -- */

.life{border-top:1px solid var(--rule-soft)}
.life > div{
  display:grid;grid-template-columns:150px 1fr;gap:14px;
  padding:14px 0;border-bottom:1px solid var(--rule-soft);
}
.life b{
  font:500 9.5px/1.9 var(--mono);letter-spacing:.14em;text-transform:uppercase;
  color:var(--accent);white-space:nowrap;
}
.life p{margin:0;font-size:14.5px;line-height:1.6;color:var(--text)}

footer{
  margin-top:96px;padding:20px 0 0;border-top:1px solid var(--rule);
  display:flex;justify-content:space-between;flex-wrap:wrap;gap:8px;
  font:400 11px/1.6 var(--mono);color:var(--muted);
}

/* ---------------------------------------------------------- responsive -- */

@media (max-width:700px){
  .cw-list{grid-template-columns:1fr}
  .life > div{grid-template-columns:1fr;gap:4px}
}
@media (max-width:560px){
  body{font-size:15.5px}
  nav.tabs .me{display:none}
  nav.tabs .in{gap:8px}
  section.s{margin-top:60px}
  .tagline{font-size:16.5px}
  .paper{grid-template-columns:1fr;gap:12px}
  .thumb{max-width:220px}
  .experience-item{grid-template-columns:30px 1fr;row-gap:4px;align-items:start}
  .company-logo{width:30px;height:30px;grid-row:span 3}
  .company-logo img,.company-logo.chip img{width:24px;height:24px}
  .experience-item time{grid-column:2;font-size:11px}
  .experience-item small{flex-basis:100%}
  .experience-item small::before{content:none}
  .experience-detail{padding-left:22px}
  .explain{position:static;width:auto;margin-top:8px}
  footer{flex-direction:column}
}

@media (prefers-reduced-motion:no-preference){
  .dot{animation:pulse 2.6s ease-in-out infinite}
  @keyframes pulse{50%{opacity:.3}}
}