/* ---------- Tokens ---------- */
:root {
  --bg: #fbfbfa;
  --surface: #ffffff;
  --text: #1c1c1c;
  --muted: #5f6368;
  --accent: #bb0000;        /* Ohio State scarlet, as a nod to the original site */
  --accent-soft: #fbe9e9;
  --border: #e4e4e0;
  --shadow: 0 1px 2px rgba(0,0,0,.05), 0 6px 20px rgba(0,0,0,.05);
  --radius: 12px;
  --maxw: 880px;
}
@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) {
    --bg: #141416;
    --surface: #1d1d20;
    --text: #ececea;
    --muted: #a3a3a0;
    --accent: #ff5c5c;
    --accent-soft: #3a1f1f;
    --border: #2c2c30;
    --shadow: 0 1px 2px rgba(0,0,0,.4), 0 6px 20px rgba(0,0,0,.35);
  }
}

/* ---------- Base ---------- */
*, *::before, *::after { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  margin: 0;
  background: var(--bg);
  color: var(--text);
  font-family: Georgia, "Times New Roman", serif;
  font-size: 1.0625rem;
  line-height: 1.65;
  -webkit-font-smoothing: antialiased;
}
h1, h2, h3, nav, .btn, .meta, .tag, footer, .site-title, .tagline {
  font-family: "Helvetica Neue", Helvetica, Arial, sans-serif;
}
h1 { font-size: clamp(1.9rem, 4vw, 2.6rem); line-height: 1.15; margin: 0 0 .35rem; letter-spacing: -.01em; }
h2 { font-size: 1.45rem; margin: 2.75rem 0 1rem; padding-bottom: .4rem; border-bottom: 1px solid var(--border); }
h3 { font-size: 1.15rem; margin: 0 0 .4rem; }
p { margin: 0 0 1rem; }
a { color: var(--accent); text-decoration: none; }
a:hover { text-decoration: underline; }
img { max-width: 100%; display: block; }
.wrap { max-width: var(--maxw); margin: 0 auto; padding: 0 16px; }

/* ---------- Header / nav ---------- */
header.site {
  border-bottom: 1px solid var(--border);
  background: var(--surface);
  position: sticky; top: 0; z-index: 10;
}
header.site .wrap {
  display: flex; align-items: center; justify-content: space-between;
  gap: 1rem; min-height: 60px; flex-wrap: wrap; padding-top: .5rem; padding-bottom: .5rem;
}
.site-title { font-weight: 700; color: var(--text); letter-spacing: -.01em; }
.site-title:hover { text-decoration: none; color: var(--accent); }
nav ul { list-style: none; margin: 0; padding: 0; display: flex; gap: .25rem; }
nav a {
  display: inline-block; padding: .4rem .75rem; border-radius: 8px;
  color: var(--muted); font-weight: 500; font-size: .95rem;
}
nav a:hover { background: var(--accent-soft); color: var(--accent); text-decoration: none; }
nav a[aria-current="page"] { color: var(--accent); background: var(--accent-soft); }

/* ---------- Hero ---------- */
.hero {
  display: grid; grid-template-columns: 1fr; gap: 1.5rem;
  align-items: center; padding: 3rem 0 1rem;
}
@media (min-width: 680px) { .hero { grid-template-columns: 1.4fr 1fr; gap: 2.5rem; } }
.hero img {
  width: 100%; aspect-ratio: 3 / 2; object-fit: cover;
  border-radius: var(--radius); box-shadow: var(--shadow);
}
.tagline { color: var(--muted); font-size: 1.05rem; line-height: 1.35; margin-bottom: 1.25rem; display: flex; align-items: center; gap: .7rem; }
.tagline .logo {
  width: 44px; height: 44px; flex: none;
  aspect-ratio: auto; object-fit: contain;
  border-radius: 0; box-shadow: none;
}
.btn-row { display: flex; flex-wrap: wrap; gap: .6rem; margin-top: 1.25rem; }
.btn {
  display: inline-flex; align-items: center; gap: .4rem;
  padding: .55rem .95rem; border-radius: 999px; font-size: .92rem; font-weight: 500;
  border: 1px solid var(--border); background: var(--surface); color: var(--text);
}
.btn:hover { border-color: var(--accent); color: var(--accent); text-decoration: none; }
.btn.primary { background: var(--accent); border-color: var(--accent); color: #fff; }
.btn.primary:hover { filter: brightness(1.08); color: #fff; }

/* ---------- Content ---------- */
main { padding-bottom: 3rem; }
.lead { font-size: 1.15rem; }
.callout {
  background: var(--surface); border: 1px solid var(--border); border-left: 4px solid var(--accent);
  border-radius: var(--radius); padding: 1rem 1.25rem; margin: 1.5rem 0;
}
.callout p { margin-bottom: .6rem; }
.callout p:last-child { margin-bottom: 0; }

/* Highlighted "curiosity" box */
.spark {
  margin: 2rem 0;
  padding: 1.5rem 1.6rem 1.4rem;
  border-radius: var(--radius);
  background: var(--accent-soft);
  border: 1px solid var(--accent);
}
.spark-kicker {
  font-family: "Helvetica Neue", Helvetica, Arial, sans-serif; font-size: .78rem; font-weight: 700;
  letter-spacing: .08em; text-transform: uppercase; color: var(--accent); margin-bottom: .6rem;
}
.spark p { font-size: 1.08rem; }
.spark p:last-child { margin-bottom: 0; }
ul.links { padding-left: 1.2rem; }
ul.links li { margin-bottom: .35rem; }

/* ---------- Cards (projects, repos) ---------- */
.card {
  background: var(--surface); border: 1px solid var(--border); border-radius: var(--radius);
  padding: 1.5rem; margin-bottom: 1.5rem; box-shadow: var(--shadow);
}
.card.project { display: grid; grid-template-columns: 1fr; gap: 1.25rem; }
@media (min-width: 680px) {
  .card.project { grid-template-columns: 1fr 240px; align-items: start; }
  .card.project.wide { grid-template-columns: 1fr; }
}
.card figure { margin: 0; }
.card figure.full { max-width: 640px; margin-top: .25rem; }
.card figure.full img { background: #fff; padding: .4rem; }
.card figure img { border-radius: 8px; border: 1px solid var(--border); background: #fff; }
.card figcaption { font-size: .85rem; color: var(--muted); margin-top: .5rem; line-height: 1.4; }
.meta { font-size: .85rem; color: var(--muted); margin-bottom: .6rem; }
.tag {
  display: inline-block; font-size: .75rem; font-weight: 600; letter-spacing: .02em;
  padding: .15rem .55rem; border-radius: 999px; background: var(--accent-soft); color: var(--accent);
  margin-right: .35rem; vertical-align: middle;
}
.repos { display: grid; grid-template-columns: 1fr; gap: 1rem; }
@media (min-width: 620px) { .repos { grid-template-columns: 1fr 1fr; } }
.repo { padding: 1.1rem 1.25rem; margin: 0; }
.repo h3 { font-size: 1rem; }
.repo h3 a { color: var(--text); }
.repo h3 a:hover { color: var(--accent); }
.repo p { font-size: .95rem; color: var(--muted); margin: .4rem 0 .6rem; }
.lang { display: inline-flex; align-items: center; gap: .4rem; font-size: .8rem; color: var(--muted); font-family: "Helvetica Neue", Helvetica, Arial, sans-serif; }
.lang::before { content: ""; width: .7rem; height: .7rem; border-radius: 50%; background: var(--dot, var(--muted)); }
.lang.julia { --dot: #9558b2; } .lang.python { --dot: #3572a5; } .lang.matlab { --dot: #e16737; }

/* ---------- Publications ---------- */
.pub { padding-left: 1rem; border-left: 3px solid var(--accent-soft); margin-bottom: 1.25rem; }
.pub .title { font-weight: 600; }
.pub .venue { color: var(--muted); font-size: .95rem; }

/* ---------- Contact ---------- */
.contact-list { list-style: none; padding: 0; margin: 1.5rem 0; display: grid; gap: .75rem; }
.contact-list li {
  display: flex; align-items: center; gap: .9rem; padding: .9rem 1.1rem;
  background: var(--surface); border: 1px solid var(--border); border-radius: var(--radius);
}
.contact-list svg { width: 22px; height: 22px; flex: none; fill: currentColor; color: var(--accent); }
.contact-list .label { font-family: "Helvetica Neue", Helvetica, Arial, sans-serif; font-size: .8rem; color: var(--muted); display: block; }

/* ---------- Footer ---------- */
footer { border-top: 1px solid var(--border); padding: 1.5rem 0 2.5rem; color: var(--muted); font-size: .85rem; }
footer .wrap { display: flex; flex-wrap: wrap; justify-content: space-between; gap: .5rem; align-items: center; }
footer span a + a { margin-left: 1rem; }
.foot-brand { display: inline-flex; align-items: center; gap: .5rem; }