/* sudshu.github.io stylesheet. Plain CSS (no Sass), loaded by _includes/head.html. */

@font-face {
  font-family: "Newsreader";
  font-style: normal;
  font-weight: 200 800;
  font-display: swap;
  src: url("../fonts/newsreader-latin-opsz-normal.woff2") format("woff2-variations"),
       url("../fonts/newsreader-latin-opsz-normal.woff2") format("woff2");
}
@font-face {
  font-family: "Public Sans";
  font-style: normal;
  font-weight: 100 900;
  font-display: swap;
  src: url("../fonts/public-sans-latin-wght-normal.woff2") format("woff2-variations"),
       url("../fonts/public-sans-latin-wght-normal.woff2") format("woff2");
}
@font-face {
  font-family: "Public Sans";
  font-style: italic;
  font-weight: 100 900;
  font-display: swap;
  src: url("../fonts/public-sans-latin-wght-italic.woff2") format("woff2-variations"),
       url("../fonts/public-sans-latin-wght-italic.woff2") format("woff2");
}

:root {
  --bg: #ffffff;
  --ink: #18222d;
  --muted: #4f5d6b;
  --accent: #1f5c99;
  --rule: #e1e6eb;
  --panel: #f4f6f8;
  --serif: "Newsreader", Georgia, "Times New Roman", serif;
  --sans: "Public Sans", system-ui, -apple-system, "Segoe UI", Roboto, sans-serif;
  --mono: ui-monospace, SFMono-Regular, Menlo, Consolas, monospace;
  --wrap: 70rem;
}

/* ---------- base ---------- */

*, *::before, *::after { box-sizing: border-box; }
html { background: var(--bg); color: var(--ink); scroll-behavior: smooth; -webkit-text-size-adjust: 100%; }
@media (prefers-reduced-motion: reduce) { html { scroll-behavior: auto; } }
body {
  margin: 0;
  font-family: var(--sans);
  font-size: 1.0625rem;
  line-height: 1.65;
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
}
a { color: var(--accent); text-underline-offset: 0.18em; text-decoration-thickness: 1px; }
a:hover { text-decoration-thickness: 2px; }
:focus-visible { outline: 2px solid var(--accent); outline-offset: 3px; border-radius: 2px; }
main:focus { outline: none; }
sub, sup { font-size: 0.7em; line-height: 0; }
img { max-width: 100%; height: auto; }
.wrap { max-width: var(--wrap); margin: 0 auto; padding: 0 clamp(1.25rem, 4vw, 2.5rem); }

.skip {
  position: absolute; left: 1rem; top: -3rem; z-index: 10;
  padding: 0.5rem 0.9rem; background: var(--ink); color: #fff; border-radius: 3px; text-decoration: none;
}
.skip:focus { top: 0.75rem; }

/* ---------- header and footer ---------- */

.site-header { border-bottom: 1px solid var(--rule); }
.site-header .wrap {
  display: flex; flex-wrap: wrap; justify-content: space-between; align-items: center;
  gap: 0.5rem 1.5rem; min-height: 4.25rem; padding-top: 0.6rem; padding-bottom: 0.6rem;
}
.site-name { font-family: var(--serif); font-size: 1.2rem; font-weight: 500; line-height: 1.2; color: var(--ink); text-decoration: none; }
.site-nav { display: flex; flex-wrap: wrap; gap: 0.25rem 1.5rem; font-size: 0.9375rem; }
.site-nav a { color: var(--muted); text-decoration: none; }
.site-nav a:hover { color: var(--ink); text-decoration: underline; }

.site-footer { margin-top: 1rem; border-top: 1px solid var(--rule); padding: 2rem 0 3rem; color: var(--muted); font-size: 0.875rem; }
.site-footer p { margin: 0; }
.contact-row, .links { display: flex; flex-wrap: wrap; gap: 0.4rem 1.5rem; margin: 0 0 0.8rem; padding: 0; list-style: none; }

/* ---------- homepage ---------- */

.intro {
  display: grid; grid-template-columns: minmax(0, 1fr) auto; gap: clamp(2rem, 5vw, 4.5rem); align-items: center;
  padding: clamp(3rem, 8vh, 5rem) 0 clamp(2.5rem, 6vh, 4rem);
}
.portrait { display: block; width: clamp(13rem, 21vw, 17rem); height: auto; aspect-ratio: 1 / 1; object-fit: cover; border-radius: 6px; background: var(--panel); }
.intro h1 {
  margin: 0 0 0.6rem; font-family: var(--serif); font-weight: 500;
  font-size: clamp(2.4rem, 4.4vw, 3.4rem); line-height: 1.05; letter-spacing: -0.015em;
}
.intro .title { margin: 0; color: var(--muted); font-size: 1rem; line-height: 1.5; }
.intro .lead { margin: 1.6rem 0 0; max-width: 42rem; font-size: 1.25rem; line-height: 1.55; }
.intro .links { margin: 1.6rem 0 0; font-size: 0.9375rem; }
.links .email, .contact-row .email { color: var(--muted); }

section.part { padding: clamp(2.5rem, 6vh, 3.75rem) 0; border-top: 1px solid var(--rule); scroll-margin-top: 1rem; }
section.part > h2 {
  margin: 0 0 1.75rem; font-family: var(--serif); font-weight: 500;
  font-size: clamp(1.7rem, 2.6vw, 2.1rem); line-height: 1.15; letter-spacing: -0.01em;
}

.topic {
  display: grid; grid-template-columns: minmax(0, 5fr) minmax(0, 7fr);
  gap: clamp(1.5rem, 4vw, 3.5rem); align-items: start; margin: 0 0 clamp(3rem, 7vh, 4.5rem);
}
.topic:last-child { margin-bottom: 0; }
.topic h3 { margin: 0 0 0.8rem; font-family: var(--serif); font-weight: 500; font-size: 1.55rem; line-height: 1.2; }
.topic p { margin: 0 0 0.85rem; }
.topic .status {
  display: inline-block; margin: 0 0 0.8rem; padding: 0.1rem 0.45rem; border-radius: 3px;
  background: #fbf1dc; color: #6a4a08; font-size: 0.8125rem; font-weight: 600;
}
.papers-h { margin: 1.1rem 0 0.4rem !important; font-size: 0.9375rem; font-weight: 600; }
.papers { margin: 0; padding: 0; list-style: none; font-size: 0.9375rem; line-height: 1.5; }
.papers li { margin: 0 0 0.45rem; }
.also { margin-top: 1rem; color: var(--muted); font-size: 0.9375rem; }
.topic-fig { margin: 0; }
.fig { background: var(--panel); border-radius: 4px; padding: clamp(0.6rem, 1.4vw, 1rem); }
.fig img { display: block; width: 100%; height: auto; background: #fff; }
.topic-fig figcaption, .prose figcaption { margin-top: 0.6rem; color: var(--muted); font-size: 0.8125rem; line-height: 1.5; }

.interests { margin: 0; padding: 0 0 0 1.1rem; max-width: 46rem; }
.interests li { margin: 0 0 0.6rem; padding-left: 0.2rem; }

.cards { display: grid; grid-template-columns: repeat(3, minmax(0, 1fr)); gap: clamp(1rem, 2.5vw, 1.75rem); margin: 0; padding: 0; list-style: none; }
.card { position: relative; display: flex; flex-direction: column; background: #fff; border: 1px solid var(--rule); border-radius: 6px; overflow: hidden; }
.card-img { display: block; width: 100%; height: auto; aspect-ratio: 16 / 9; object-fit: cover; border-bottom: 1px solid var(--rule); }
.card-body { padding: 1rem 1.1rem 1.25rem; }
.card time { color: var(--muted); font-size: 0.875rem; font-variant-numeric: tabular-nums; }
.card-title { margin: 0.35rem 0 0.5rem; font-family: var(--serif); font-weight: 500; font-size: 1.2rem; line-height: 1.3; }
.card-title a { color: var(--accent); text-decoration: none; }
.card-title a::after { content: ""; position: absolute; inset: 0; }  /* the whole card is the link */
.card-title a:focus-visible { outline: none; }
.card:focus-within { outline: 2px solid var(--accent); outline-offset: 3px; }
.card p { margin: 0; color: var(--muted); font-size: 0.9375rem; line-height: 1.5; }
@media (hover: hover) and (pointer: fine) {
  .card { transition: transform 0.25s ease, box-shadow 0.25s ease; }
  .card:hover { transform: translateY(-4px); box-shadow: 0 14px 32px rgba(24, 34, 45, 0.14); }
  .card:hover .card-title a { text-decoration: underline; }
}
@media (hover: hover) and (pointer: fine) and (prefers-reduced-motion: reduce) { .card:hover { transform: none; } }

.explainer { display: grid; grid-template-columns: minmax(0, 5fr) minmax(0, 7fr); gap: clamp(1.5rem, 4vw, 3.5rem); align-items: center; }
.explainer h3 { margin: 0 0 0.6rem; font-family: var(--serif); font-weight: 500; font-size: 1.4rem; line-height: 1.25; }
.explainer p { margin: 0; }
.explainer-media { position: relative; }
.explainer-video { display: block; width: 100%; height: auto; border: 1px solid var(--rule); border-radius: 4px; background: #0b1622; }
.video-toggle {
  position: absolute; right: 0.6rem; bottom: 0.6rem; z-index: 2;
  font: 500 0.8125rem/1 var(--sans); color: #e6edf3; background: rgba(8, 17, 28, 0.72);
  border: 1px solid rgba(255, 255, 255, 0.28); border-radius: 999px; padding: 0.45rem 0.8rem; cursor: pointer;
}
.video-toggle:hover { background: rgba(8, 17, 28, 0.9); }
.video-toggle:focus-visible { outline: 2px solid #ffffff; outline-offset: 2px; }

.about p { max-width: 46rem; margin: 0 0 0.9rem; }

/* Figures pop slightly when the mouse is over them (pointer devices only). */
.topic-fig .fig, .explainer-video { position: relative; z-index: 0; }
.topic-fig .fig { transform-origin: 50% 100%; }  /* grow upward so the caption below stays clear */
@media (hover: hover) and (pointer: fine) {
  .topic-fig .fig, .explainer-video { transition: transform 0.25s ease, box-shadow 0.25s ease; }
  .topic-fig .fig:hover, .explainer-link:hover .explainer-video {
    z-index: 1;
    transform: scale(1.05);
    box-shadow: 0 14px 36px rgba(24, 34, 45, 0.2);
  }
}
@media (hover: hover) and (pointer: fine) and (prefers-reduced-motion: reduce) {
  .topic-fig .fig, .explainer-video { transition: box-shadow 0.25s ease; }
  .topic-fig .fig:hover, .explainer-link:hover .explainer-video { transform: none; }
}

/* ---------- posts and pages ---------- */

.prose { max-width: 44rem; margin: 0 auto; padding: clamp(2.5rem, 7vh, 4rem) 0 2rem; line-height: 1.7; }
.post-header { margin-bottom: 2rem; }
.post-title, .page-title {
  margin: 0 0 0.5rem; font-family: var(--serif); font-weight: 500;
  font-size: clamp(2rem, 4vw, 2.7rem); line-height: 1.12; letter-spacing: -0.015em;
}
.post-meta { margin: 0; color: var(--muted); font-size: 0.9375rem; }
.prose h1, .prose h2, .prose h3, .prose h4 { font-family: var(--serif); font-weight: 500; line-height: 1.25; }
.prose h1 { font-size: 2.1rem; }
.prose h2 { margin: 2.4rem 0 0.8rem; font-size: 1.6rem; }
.prose h3 { margin: 2rem 0 0.6rem; font-size: 1.3rem; }
.prose h4 { margin: 1.6rem 0 0.5rem; font-size: 1.1rem; }
.prose p, .prose ul, .prose ol, .prose blockquote, .prose table, .prose pre { margin: 0 0 1.1rem; }
.prose ul, .prose ol { padding-left: 1.4rem; }
.prose li { margin: 0 0 0.4rem; }
.prose img { display: block; margin: 1.6rem auto; border-radius: 4px; }
.prose figure { margin: 1.6rem 0; }
.prose blockquote { margin-left: 0; padding: 0.2rem 0 0.2rem 1rem; border-left: 3px solid var(--rule); color: var(--muted); }
.prose hr { margin: 2.4rem 0; border: 0; border-top: 1px solid var(--rule); }
.prose table { width: 100%; border-collapse: collapse; font-size: 0.9375rem; display: block; overflow-x: auto; }
.prose th, .prose td { padding: 0.5rem 0.75rem; border-bottom: 1px solid var(--rule); text-align: left; vertical-align: top; }
.prose th { font-weight: 600; }
.prose code { font-family: var(--mono); font-size: 0.88em; background: var(--panel); border-radius: 3px; padding: 0.1em 0.3em; }
.prose pre { overflow-x: auto; padding: 0.9rem 1.1rem; background: var(--panel); border: 1px solid var(--rule); border-radius: 4px; line-height: 1.5; }
.prose pre code { background: none; padding: 0; font-size: 0.85rem; }
.post-back { margin-top: 3rem; padding-top: 1.2rem; border-top: 1px solid var(--rule); font-size: 0.9375rem; }

/* The adjoint post's widgets set their small headings in amber #d97706 (3.2:1 on white).
   Darken them to #b45309 (5.0:1) without editing the post. */
.post-content .iw-card .iw-eyebrow { color: #b45309; }

/* poem posts */
.poem { margin: 2rem 0 2.4rem; font-family: var(--serif); font-size: 1.2rem; line-height: 1.6; }
.poem p { margin: 0 0 1.4rem; }
.poem .line { display: block; padding-left: 1.5em; text-indent: -1.5em; }  /* wrapped lines get a hanging indent */

/* code highlighting (Rouge), light */
.highlight .c, .highlight .c1, .highlight .cm, .highlight .cs, .highlight .cp { color: #5b6b79; font-style: italic; }
.highlight .k, .highlight .kd, .highlight .kn, .highlight .kp, .highlight .kr, .highlight .kc, .highlight .ow { color: #8a2c5a; }
.highlight .s, .highlight .s1, .highlight .s2, .highlight .sb, .highlight .sd, .highlight .se, .highlight .si, .highlight .sx { color: #2a6a35; }
.highlight .m, .highlight .mi, .highlight .mf, .highlight .mh, .highlight .il { color: #9a5200; }
.highlight .nf, .highlight .fm, .highlight .nc { color: #1f5c99; }
.highlight .nb, .highlight .bp { color: #6a4a08; }
.highlight .o, .highlight .p { color: #3b4a58; }
.highlight .gd { color: #a12d2d; }
.highlight .gi { color: #2a6a35; }
.highlight .err { color: inherit; background: none; }

/* ---------- small screens ---------- */

@media (max-width: 900px) {
  .topic, .explainer { grid-template-columns: 1fr; }
  .topic-fig, .explainer-media { max-width: 44rem; }
}
@media (max-width: 760px) {
  .intro { grid-template-columns: 1fr; gap: 1.5rem; }
  .portrait { order: -1; width: 8.5rem; }
  .site-nav { width: 100%; gap: 0.25rem 1.1rem; font-size: 0.9rem; }
  .poem { font-size: 1.08rem; }
  .cards { grid-template-columns: 1fr; }
  .intro .lead { font-size: 1.15rem; }
}