/* Bipin Lekhak — site styles */

:root {
  --bg: #fbfaf7;
  --surface: #ffffff;
  --surface-2: #f3f1ec;
  --ink: #1c2229;
  --muted: #535c68;
  --faint: #7f8893;
  --rule: #e3e0d8;
  --rule-strong: #cfcbc1;
  --accent: #0b4f8a;
  --accent-ink: #083b68;
  --accent-soft: #e7eff7;
  --warm: #a8501c;
  --warm-soft: #f8ece3;

  --serif: "Source Serif 4", "Source Serif Pro", Georgia, "Times New Roman", serif;
  --sans: "Inter", system-ui, -apple-system, "Segoe UI", Roboto, sans-serif;
  --mono: ui-monospace, "SFMono-Regular", Menlo, Consolas, monospace;

  --measure: 46rem;
  --gutter: 1rem;
  color-scheme: light dark;
}

@media (prefers-color-scheme: dark) {
  :root {
    --bg: #111519;
    --surface: #171c21;
    --surface-2: #1d232a;
    --ink: #e5e8ec;
    --muted: #a7b0ba;
    --faint: #7c8590;
    --rule: #262d35;
    --rule-strong: #36404a;
    --accent: #82b6e8;
    --accent-ink: #a9cdf0;
    --accent-soft: #19283a;
    --warm: #eb9a68;
    --warm-soft: #33241b;
  }
}

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

html { -webkit-text-size-adjust: 100%; scroll-padding-top: 4.5rem; }

body {
  margin: 0;
  background: var(--bg);
  color: var(--ink);
  font-family: var(--sans);
  font-size: 1rem;
  line-height: 1.65;
  text-rendering: optimizeLegibility;
  -webkit-font-smoothing: antialiased;
}

@media (min-width: 40rem) {
  :root { --gutter: 1.5rem; }
  body { font-size: 1.0625rem; }
}

a { color: var(--accent); text-decoration-thickness: 1px; text-underline-offset: 0.18em; }
a:hover { color: var(--accent-ink); text-decoration-thickness: 2px; }
a:focus-visible { outline: 2px solid var(--accent); outline-offset: 2px; border-radius: 2px; }

img, svg { max-width: 100%; height: auto; }

h1, h2, h3 { font-family: var(--serif); font-weight: 600; line-height: 1.2; color: var(--ink); }

.wrap {
  width: 100%;
  max-width: calc(var(--measure) + 2 * var(--gutter));
  margin: 0 auto;
  padding: 0 var(--gutter);
}

.skip-link {
  position: absolute; left: -999px; top: 0.5rem;
  background: var(--surface); padding: 0.5rem 0.75rem; z-index: 10;
}
.skip-link:focus { left: 0.5rem; }

/* Header */

.site-header {
  position: sticky; top: 0; z-index: 5;
  background: color-mix(in srgb, var(--bg) 88%, transparent);
  backdrop-filter: saturate(1.4) blur(10px);
  -webkit-backdrop-filter: saturate(1.4) blur(10px);
  border-bottom: 1px solid var(--rule);
}

.header-inner {
  display: flex; flex-wrap: wrap; align-items: baseline; justify-content: space-between;
  gap: 0.25rem 1.5rem; padding-top: 0.7rem; padding-bottom: 0.7rem;
}

.brand {
  font-family: var(--serif); font-weight: 700; font-size: 1.15rem;
  color: var(--ink); text-decoration: none; letter-spacing: -0.01em;
}
.brand:hover { color: var(--accent); }

.site-nav { display: flex; flex-wrap: wrap; gap: 0.15rem 1.1rem; font-size: 0.92rem; }
.site-nav a { color: var(--muted); text-decoration: none; font-weight: 500; }
.site-nav a:hover, .site-nav a[aria-current="page"] { color: var(--accent); }

/* Sections */

main { padding-bottom: 3rem; }

.section { padding-top: 2.75rem; }

.section-title {
  font-size: 0.78rem; font-family: var(--sans); font-weight: 600;
  letter-spacing: 0.12em; text-transform: uppercase; color: var(--faint);
  margin: 0 0 1.25rem; padding-bottom: 0.5rem; border-bottom: 1px solid var(--rule);
}

/* Hero */

.hero { display: grid; gap: 1.75rem; padding-top: 3rem; }
.hero.has-photo { grid-template-columns: 1fr; }
@media (min-width: 40rem) {
  .hero.has-photo { grid-template-columns: 1fr 10rem; align-items: start; }
}

.hero h1 {
  font-size: clamp(2.2rem, 7vw, 3.1rem); font-weight: 700; letter-spacing: -0.02em;
  margin: 0 0 0.35rem;
}

.role { margin: 0 0 1.5rem; color: var(--muted); font-size: 1.02rem; line-height: 1.5; }
.role strong { color: var(--ink); font-weight: 600; }

.hero p.bio { margin: 0 0 1rem; }

.hero-photo img {
  display: block; width: 10rem; height: 10rem; object-fit: cover; border-radius: 50%;
  border: 1px solid var(--rule);
}
@media (max-width: 39.99rem) {
  .hero-photo { order: -1; }
  .hero-photo img { width: 7.5rem; height: 7.5rem; }
}

.callout {
  margin: 1.5rem 0 0; padding: 0.8rem 1rem; border-radius: 8px;
  background: var(--accent-soft); color: var(--ink); font-size: 0.95rem;
  border-left: 3px solid var(--accent);
}

.contact {
  list-style: none; padding: 0; margin: 1.5rem 0 0;
  display: flex; flex-wrap: wrap; gap: 0.5rem;
}
.contact a {
  display: inline-flex; align-items: center; gap: 0.45rem;
  padding: 0.38rem 0.8rem; border: 1px solid var(--rule-strong); border-radius: 999px;
  color: var(--ink); text-decoration: none; font-size: 0.9rem; font-weight: 500;
  background: var(--surface);
}
.contact a:hover { border-color: var(--accent); color: var(--accent); }
.contact svg { width: 1rem; height: 1rem; flex: none; fill: currentColor; }

/* News */

.news { list-style: none; padding: 0; margin: 0; }
.news li {
  display: grid; grid-template-columns: 5.5rem 1fr; gap: 1rem;
  padding: 0.4rem 0; font-size: 0.97rem;
}
.news .when { color: var(--faint); font-variant-numeric: tabular-nums; font-size: 0.9rem; padding-top: 0.05rem; }

/* Research */

.lede { font-size: 1.05rem; color: var(--muted); margin: 0 0 1.5rem; }

.theme { padding: 1.25rem 0; border-top: 1px solid var(--rule); }
.theme:first-of-type { border-top: 0; padding-top: 0; }
.theme h3 { font-size: 1.3rem; margin: 0 0 0.5rem; }
.theme p { margin: 0 0 0.75rem; }

.keywords { list-style: none; padding: 0; margin: 0.5rem 0 0; display: flex; flex-wrap: wrap; gap: 0.4rem; }
.keywords li, .tags li {
  font-size: 0.78rem; color: var(--muted); background: var(--surface-2);
  border-radius: 4px; padding: 0.12rem 0.5rem;
}

figure.diagram { margin: 1.25rem 0 1rem; }
.diagram-scroll {
  overflow-x: auto; border: 1px solid var(--rule); border-radius: 10px;
  background: var(--surface); padding: 0.75rem;
}
.diagram-scroll svg { display: block; min-width: 36rem; width: 100%; }
figure.diagram figcaption { font-size: 0.88rem; color: var(--muted); margin-top: 0.6rem; line-height: 1.5; }

.dg-box { fill: var(--surface-2); stroke: var(--rule-strong); stroke-width: 1; }
.dg-box.native { fill: var(--accent-soft); stroke: var(--accent); }
.dg-box.response { fill: var(--warm-soft); stroke: var(--warm); }
.dg-ode { fill: var(--surface); stroke: var(--ink); stroke-width: 1.25; }
.dg-text { fill: var(--ink); font-family: var(--sans); font-size: 13px; }
.dg-small { fill: var(--muted); font-family: var(--sans); font-size: 11.5px; }
.dg-strong { font-weight: 600; }
.dg-math { font-family: var(--serif); font-style: italic; font-size: 15px; fill: var(--ink); }
.dg-native { fill: var(--accent); }
.dg-response { fill: var(--warm); }
.dg-line { stroke: var(--faint); stroke-width: 1.25; fill: none; }
.dg-head { fill: var(--faint); }

/* Publications */

.pub-group + .pub-group { margin-top: 2rem; }
.pub-group h3 {
  font-family: var(--sans); font-size: 0.95rem; font-weight: 600; color: var(--muted);
  margin: 0 0 0.75rem;
}

.pubs { list-style: none; padding: 0; margin: 0; }
.pub { padding: 0.9rem 0; border-top: 1px solid var(--rule); }
.pub:first-child { border-top: 0; padding-top: 0; }

.pub-venue {
  display: inline-block; font-size: 0.72rem; font-weight: 600; letter-spacing: 0.04em;
  text-transform: uppercase; color: var(--accent); background: var(--accent-soft);
  border-radius: 4px; padding: 0.1rem 0.45rem; margin-bottom: 0.35rem;
}
.pub-venue.review { color: var(--warm); background: var(--warm-soft); }

.pub-title { font-family: var(--serif); font-size: 1.12rem; font-weight: 600; line-height: 1.35; margin: 0 0 0.2rem; }
.pub-authors { margin: 0; color: var(--muted); font-size: 0.93rem; }
.pub-authors .me { color: var(--ink); font-weight: 600; }
.pub-where { margin: 0; color: var(--faint); font-size: 0.9rem; font-style: italic; }
.pub-summary { margin: 0.45rem 0 0; font-size: 0.93rem; color: var(--muted); }
.pub-links { display: flex; flex-wrap: wrap; gap: 0.75rem; margin-top: 0.35rem; font-size: 0.88rem; font-weight: 500; }

/* Experience */

.timeline { list-style: none; padding: 0; margin: 0; }
.timeline li { display: grid; gap: 0.1rem 1.25rem; padding: 0.75rem 0; border-top: 1px solid var(--rule); }
.timeline li:first-child { border-top: 0; padding-top: 0; }
@media (min-width: 40rem) {
  .timeline li { grid-template-columns: 9rem 1fr; }
}
.timeline .when { color: var(--faint); font-size: 0.9rem; font-variant-numeric: tabular-nums; padding-top: 0.1rem; }
.timeline .what { margin: 0; font-weight: 600; }
.timeline .where { margin: 0; color: var(--muted); font-size: 0.95rem; }
.timeline .detail { margin: 0.3rem 0 0; font-size: 0.93rem; color: var(--muted); }

.subhead { font-family: var(--sans); font-size: 0.95rem; font-weight: 600; color: var(--muted); margin: 2rem 0 0.75rem; }

/* Archive */

.note-list { list-style: none; padding: 0; margin: 0; }
.note-list li { padding: 0.55rem 0; border-top: 1px solid var(--rule); }
.note-list li:first-child { border-top: 0; }
.note-list a { font-family: var(--serif); font-size: 1.08rem; font-weight: 600; text-decoration: none; }
.note-list a:hover { text-decoration: underline; }
.note-meta { display: block; color: var(--faint); font-size: 0.85rem; }


.page-head { padding-top: 3rem; }
.page-head h1 { font-size: clamp(2rem, 6vw, 2.6rem); margin: 0 0 0.5rem; letter-spacing: -0.015em; }

/* Posts */

.post-head { padding-top: 3rem; margin-bottom: 2rem; }
.post-head h1 { font-size: clamp(1.9rem, 6vw, 2.6rem); margin: 0.3rem 0 0.75rem; letter-spacing: -0.015em; }
.eyebrow { margin: 0; font-size: 0.85rem; color: var(--faint); }
.eyebrow a { color: var(--accent); text-decoration: none; font-weight: 500; }
.tags { list-style: none; padding: 0; margin: 0; display: flex; flex-wrap: wrap; gap: 0.35rem; }

.prose { font-family: var(--serif); font-size: 1.1rem; line-height: 1.7; }
.prose h2 { font-size: 1.5rem; margin: 2.2rem 0 0.75rem; }
.prose h3 { font-size: 1.22rem; margin: 1.8rem 0 0.6rem; }
.prose h4 { font-size: 1.05rem; margin: 1.5rem 0 0.5rem; }
.prose p, .prose ul, .prose ol { margin: 0 0 1.1rem; }
.prose li + li { margin-top: 0.3rem; }
.prose img { display: block; margin: 1.5rem auto; border-radius: 6px; background: #fff; }
.prose blockquote {
  margin: 1.5rem 0; padding: 0.25rem 0 0.25rem 1rem; border-left: 3px solid var(--rule-strong);
  color: var(--muted); font-style: italic;
}
.prose table { border-collapse: collapse; margin: 1.5rem 0; font-size: 0.95rem; display: block; overflow-x: auto; }
.prose th, .prose td { border: 1px solid var(--rule); padding: 0.4rem 0.7rem; text-align: left; }
.prose hr { border: 0; border-top: 1px solid var(--rule); margin: 2rem 0; }
.prose code { font-family: var(--mono); font-size: 0.85em; background: var(--surface-2); padding: 0.1em 0.35em; border-radius: 4px; }
.prose pre { background: var(--surface-2); padding: 1rem; border-radius: 8px; overflow-x: auto; font-size: 0.88rem; line-height: 1.5; }
.prose pre code { background: none; padding: 0; }
.prose mjx-container[display="true"] { overflow-x: auto; overflow-y: hidden; padding: 0.25rem 0; }

.post-foot { margin-top: 3rem; padding-top: 1rem; border-top: 1px solid var(--rule); font-weight: 500; }

/* Footer */

.site-footer { border-top: 1px solid var(--rule); color: var(--faint); font-size: 0.85rem; }
.footer-inner { display: flex; flex-wrap: wrap; justify-content: space-between; gap: 0.25rem 1.5rem; padding-top: 1.25rem; padding-bottom: 2rem; }
.footer-inner p { margin: 0; }
.site-footer a { color: var(--muted); }

@media (prefers-reduced-motion: no-preference) {
  html { scroll-behavior: smooth; }
}

@media print {
  .site-header, .site-footer, .skip-link { display: none; }
  body { background: #fff; color: #000; }
}