/* Rubin twilight: dark "summit night" by default, warm "golden hour" light mode.
   System fonts only, so the page makes no third-party requests. */
:root {
  --bg: #101728;
  --bg-alt: #151d34;
  --card: #19223a;
  --ink: #F6EEE3;
  --muted: #BDB0A1;
  --rule: #2A3552;
  --accent: #FFB347;      /* links and buttons on dark */
  --accent-ink: #2B1A05;
  --lagoon: #6FD3CB;
  --hero-scrim: linear-gradient(180deg, rgba(8,12,24,.72) 0%, rgba(8,12,24,.45) 45%, rgba(16,23,40,.92) 100%);
  --serif: Newsreader, Georgia, "Times New Roman", serif;
  --sans: "Avenir Next", "Segoe UI", system-ui, -apple-system, sans-serif;
  --mono: ui-monospace, "SF Mono", Menlo, Consolas, monospace;
}
:root[data-theme="light"] {
  --bg: #FFFBF6;
  --bg-alt: #FBF1E4;
  --card: #FFFFFF;
  --ink: #2B2420;
  --muted: #6A5E55;
  --rule: #EBDDCE;
  --accent: #B8431E;      /* ember, 5.3:1 on paper */
  --accent-ink: #FFFFFF;
  --lagoon: #0E6E78;
  --hero-scrim: linear-gradient(180deg, rgba(8,12,24,.70) 0%, rgba(8,12,24,.42) 45%, rgba(255,251,246,.95) 100%);
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; scroll-padding-top: 64px; -webkit-text-size-adjust: 100%; }
body {
  margin: 0; background: var(--bg); color: var(--ink);
  font: 18px/1.65 var(--serif);
  padding-left: max(0px, env(safe-area-inset-left)); padding-right: max(0px, env(safe-area-inset-right));
}
a { color: var(--accent); text-underline-offset: 3px; }
a:focus-visible, button:focus-visible, summary:focus-visible, .term:focus-visible { outline: 3px solid var(--lagoon); outline-offset: 3px; border-radius: 4px; }
h1, h2, h3, h4 { font-family: var(--sans); letter-spacing: -.01em; margin: 0; }
p { margin: 0 0 1em; }
code { font-family: var(--mono); font-size: .88em; }
.skip { position: absolute; left: -999px; top: 8px; background: var(--accent); color: var(--accent-ink); padding: 8px 12px; border-radius: 6px; z-index: 20; }
.skip:focus { left: 8px; }

/* nav */
.nav {
  position: sticky; top: 0; z-index: 10; display: flex; align-items: center; gap: 16px;
  padding: 10px 20px; background: color-mix(in srgb, var(--bg) 88%, transparent);
  backdrop-filter: blur(8px); border-bottom: 1px solid var(--rule);
}
.brand { font: 800 .8rem var(--sans); letter-spacing: .16em; text-transform: uppercase; color: var(--ink); text-decoration: none; white-space: nowrap; }
.nav nav { display: flex; gap: 4px 16px; flex: 1; overflow-x: auto; scrollbar-width: none; justify-content: flex-end; }
.nav nav::-webkit-scrollbar { display: none; }
.nav nav a { font: 600 .74rem var(--sans); letter-spacing: .1em; text-transform: uppercase; color: var(--muted); text-decoration: none; padding: 8px 2px; white-space: nowrap; }
.nav nav a:hover { color: var(--accent); }
.burger { display: none; font: 600 .72rem var(--sans); letter-spacing: .1em; text-transform: uppercase; color: var(--ink); background: transparent; border: 1.5px solid var(--rule); border-radius: 999px; padding: 7px 12px; cursor: pointer; }
.burger:hover { border-color: var(--accent); color: var(--accent); }
.theme { font: 600 .72rem var(--sans); letter-spacing: .1em; text-transform: uppercase; color: var(--ink); background: transparent; border: 1.5px solid var(--rule); border-radius: 999px; padding: 7px 12px; cursor: pointer; }
.theme:hover { border-color: var(--accent); color: var(--accent); }

/* hero */
.hero {
  position: relative; min-height: 88vh; display: grid; place-items: center; padding: 56px 20px 72px;
  background: var(--hero-scrim), url("img/rubin-sunset.jpg") center 62% / cover no-repeat;
  color: #F6EEE3;
}
.hero::before { content: ""; position: absolute; inset: 0; background: url("img/stars.svg") center top / cover no-repeat; opacity: .55; pointer-events: none; }
.hero-inner { position: relative; display: flex; align-items: center; justify-content: center; gap: clamp(24px, 5vw, 64px); flex-wrap: wrap; max-width: 880px; }
.portrait { width: 260px; height: 260px; border-radius: 50%; object-fit: cover; border: 3px solid rgba(255,179,71,.9); box-shadow: 0 0 0 8px rgba(255,179,71,.14), 0 18px 50px rgba(0,0,0,.5); }
.hero-text { max-width: 430px; text-align: center; }
.rule { height: 1px; margin: 6px auto; background: linear-gradient(90deg, transparent, #FFB347, transparent); }
.hero h1 { font-weight: 800; font-size: clamp(1.7rem, 4.6vw, 2.4rem); line-height: 1.12; letter-spacing: .14em; text-transform: uppercase; margin: 12px 0; text-shadow: 0 2px 14px rgba(0,0,0,.45); }
.role { font: 500 .8rem/1.9 var(--sans); letter-spacing: .2em; text-transform: uppercase; color: #E9DCCB; margin: 16px 0 0; }
.pitch { font-size: 1.12rem; margin: 20px 0 0; text-shadow: 0 1px 10px rgba(0,0,0,.5); }
.hero-links { margin: 24px 0 0; display: flex; gap: 10px; justify-content: center; flex-wrap: wrap; }
.btn { display: inline-block; font: 700 .76rem/1 var(--sans); letter-spacing: .14em; text-transform: uppercase; text-decoration: none; padding: 13px 18px; border-radius: 999px; background: #FFB347; color: #2B1A05; border: 1.5px solid #FFB347; }
.btn:hover { background: #FFC76E; }
.btn.ghost { background: rgba(8,12,24,.35); color: #FFB347; }
.btn.ghost:hover { background: #FFB347; color: #2B1A05; }
.hero-credit { position: absolute; bottom: 10px; left: 0; right: 0; margin: 0; text-align: center; font: .72rem var(--sans); letter-spacing: .04em; color: #D9CBB8; opacity: .85; }

/* bands */
.band { padding: 72px 20px; }
.band.alt { background: var(--bg-alt); }
.wrap { max-width: 1040px; margin: 0 auto; }
.wrap.narrow { max-width: 720px; }
.center { text-align: center; }
.band h2 { font-weight: 800; font-size: clamp(1.5rem, 3vw, 2rem); letter-spacing: .12em; text-transform: uppercase; margin-bottom: 8px; }
.band h2::after { content: ""; display: block; width: 56px; height: 2px; background: var(--accent); margin: 14px 0 28px; }
.center h2::after { margin-inline: auto; }
.lead { font-size: 1.1rem; color: var(--muted); max-width: 62ch; margin-bottom: 28px; }
.center .lead { margin-inline: auto; }
.quiet { font: .9rem/1.5 var(--sans); color: var(--muted); }
.tag { font: 600 .66rem var(--sans); letter-spacing: .08em; text-transform: uppercase; color: var(--accent); border: 1px solid var(--accent); border-radius: 999px; padding: 3px 9px; margin-left: 8px; vertical-align: middle; white-space: nowrap; }

/* research */
.topic { padding: 32px 0; border-top: 1px solid var(--rule); display: grid; gap: 32px; }
.topic:first-of-type { border-top: 0; padding-top: 8px; }
.topic.with-photo { grid-template-columns: minmax(0, 1.25fr) minmax(0, 1fr); align-items: start; }
.topic h3 { font-size: 1.35rem; margin-bottom: 14px; }
.topic h4 { font-size: .98rem; margin: 22px 0 6px; color: var(--lagoon); }
.plain { background: var(--card); border-left: 3px solid var(--lagoon); padding: 14px 18px; border-radius: 0 10px 10px 0; }
.tight { padding-left: 1.2em; margin: 0 0 1em; }
.tight li { margin-bottom: .6em; }
.photo { margin: 0; }
.photo img { width: 100%; height: auto; border-radius: 14px; display: block; border: 1px solid var(--rule); }
.photo figcaption { font: .8rem/1.4 var(--sans); color: var(--muted); margin-top: 8px; }
.photo.tall img { max-height: 520px; object-fit: cover; }
.photo.fullframe img { max-height: none; }
.two { display: grid; grid-template-columns: minmax(0, 1.4fr) minmax(0, 1fr); gap: 40px; align-items: start; }
.two h3 { font-size: 1.15rem; margin: 0 0 12px; }
.two h3:not(:first-child) { margin-top: 26px; }

/* video: click-to-play, so no request goes to YouTube until the visitor presses play */
.video { margin: 12px 0 0; padding-top: 32px; border-top: 1px solid var(--rule); max-width: 820px; }
.player { position: relative; aspect-ratio: 16 / 9; border-radius: 14px; overflow: hidden; border: 1px solid var(--rule);
  background: linear-gradient(rgba(8,12,24,.25), rgba(8,12,24,.45)), url("img/rubin-sunset.jpg") center 60% / cover no-repeat; }
.player iframe { position: absolute; inset: 0; width: 100%; height: 100%; border: 0; }
.play { position: absolute; inset: 0; width: 100%; height: 100%; display: grid; place-items: center; background: transparent; border: 0; cursor: pointer; }
.play .tri { width: 76px; height: 76px; border-radius: 50%; background: #FFB347; box-shadow: 0 8px 30px rgba(0,0,0,.45); position: relative; transition: transform .15s; }
.play .tri::after { content: ""; position: absolute; left: 31px; top: 24px; border-style: solid; border-width: 14px 0 14px 23px; border-color: transparent transparent transparent #2B1A05; }
.play:hover .tri { transform: scale(1.07); }
.play:focus-visible { outline: 3px solid var(--lagoon); outline-offset: -6px; }
.video figcaption { font: .85rem/1.5 var(--sans); color: var(--muted); margin-top: 10px; }

/* glossary terms */
.term { border-bottom: 2px dotted var(--accent); cursor: help; position: relative; }
.term::after {
  content: attr(data-def); position: absolute; left: 0; bottom: calc(100% + 8px); width: max-content; max-width: 280px;
  background: var(--card); color: var(--ink); border: 1px solid var(--rule); border-radius: 10px; padding: 10px 12px;
  font: .82rem/1.45 var(--sans); box-shadow: 0 10px 28px rgba(0,0,0,.35); z-index: 5; display: none; pointer-events: none;
}
.term:hover::after, .term:focus::after { display: block; }

/* software */
.cards { display: grid; grid-template-columns: repeat(auto-fill, minmax(230px, 1fr)); gap: 14px; margin-bottom: 18px; }
.card { display: block; background: var(--card); border: 1px solid var(--rule); border-radius: 14px; padding: 18px; text-decoration: none; color: var(--ink); transition: border-color .15s, transform .15s; }
.card:hover { border-color: var(--accent); transform: translateY(-2px); }
.card h3 { font-size: 1.02rem; color: var(--accent); margin-bottom: 6px; }
.card p { font-size: .95rem; line-height: 1.5; color: var(--muted); margin: 0; }

/* publications */
.pubs { list-style: none; padding: 0; margin: 0 0 24px; display: grid; gap: 16px; }
.pubs li { background: var(--card); border: 1px solid var(--rule); border-radius: 14px; padding: 16px 18px; }
.pubs .t { font: 700 1rem/1.35 var(--sans); }
.pubs .t a { color: var(--ink); text-decoration-color: var(--accent); }
.pubs .m { font: .85rem/1.5 var(--sans); color: var(--muted); margin-top: 4px; }
.pubs .m b { color: var(--ink); }
.pubs .why { font-size: .96rem; margin: 8px 0 0; }
.all { margin-bottom: 20px; }
.all summary { cursor: pointer; font: 700 .85rem var(--sans); letter-spacing: .08em; text-transform: uppercase; color: var(--accent); padding: 8px 0; }
.all h3 { font-size: .95rem; letter-spacing: .1em; color: var(--lagoon); margin: 22px 0 8px; }
.all ul { list-style: none; margin: 0; padding: 0; }
.all li { font: .92rem/1.45 var(--sans); padding: 8px 0; border-top: 1px solid var(--rule); }
.all li b { font-weight: 700; }
.all li span { color: var(--muted); display: block; }

/* talks */
.talks { list-style: none; margin: 0; padding: 0; }
.talks li { padding: 10px 0; border-top: 1px solid var(--rule); font-size: 1rem; line-height: 1.45; display: grid; grid-template-columns: 84px 1fr; gap: 12px; }
.talks li:first-child { border-top: 0; }
.talks span { font: 700 .76rem var(--sans); letter-spacing: .08em; text-transform: uppercase; color: var(--accent); padding-top: 3px; }

/* glossary */
.gl { display: grid; gap: 12px; margin: 0; }
.gl div { background: var(--card); border: 1px solid var(--rule); border-radius: 12px; padding: 14px 16px; }
.gl dt { font: 700 .98rem var(--sans); color: var(--lagoon); margin-bottom: 4px; }
.gl dd { margin: 0; font-size: .98rem; line-height: 1.55; }

/* contact */
.mail { font: 700 1.3rem var(--sans); letter-spacing: .02em; margin: 8px 0 22px; }
.links { list-style: none; padding: 0; margin: 0 0 24px; display: flex; gap: 10px; justify-content: center; flex-wrap: wrap; }
.links a { display: inline-block; font: 700 .76rem/1 var(--sans); letter-spacing: .14em; text-transform: uppercase; color: var(--accent); text-decoration: none; padding: 12px 16px; border: 1.5px solid var(--accent); border-radius: 999px; }
.links a:hover { background: var(--accent); color: var(--accent-ink); }

footer { text-align: center; padding: 28px 20px 40px; font: .85rem var(--sans); color: var(--muted); border-top: 1px solid var(--rule); }
footer p { margin: 0; }

/* narrow screens: pin the definition to the bottom of the viewport so it can never overflow sideways */
@media (max-width: 860px) {
  .topic.with-photo, .two { grid-template-columns: minmax(0, 1fr); }
  .term::after { position: fixed; left: 16px; right: 16px; bottom: 16px; width: auto; max-width: none; }
  .photo.tall img { max-height: 460px; }
  .photo.fullframe img { max-height: none; }
  /* no JavaScript: links wrap onto two rows so every section stays reachable */
  .nav { flex-wrap: wrap; gap: 4px 12px; padding: 8px 14px 6px; }
  .brand { margin-right: auto; }
  .nav nav { order: 3; width: 100%; flex: none; flex-wrap: wrap; overflow: visible; justify-content: flex-start; gap: 0 14px; }
  .nav nav a { padding: 6px 0; }
  html { scroll-padding-top: 104px; }
  /* with JavaScript: one slim bar (name, Menu, theme) and a dropdown list, like a phone app */
  .js .nav { flex-wrap: wrap; gap: 0 10px; padding: 8px 14px; min-height: 54px; }
  .js .burger { display: inline-flex; align-items: center; gap: 8px; }
  .js .nav nav { display: none; order: 3; width: 100%; flex-direction: column; flex-wrap: nowrap; gap: 0; margin: 8px -14px -8px; padding: 6px 14px 12px; border-top: 1px solid var(--rule); background: var(--bg); }
  .js .nav.open nav { display: flex; }
  .js .nav nav a { font-size: .86rem; padding: 14px 4px; border-bottom: 1px solid var(--rule); color: var(--ink); }
  .js .nav nav a:last-child { border-bottom: 0; }
  .js { scroll-padding-top: 70px; }
}
@media (max-width: 620px) {
  body { font-size: 17px; }
  .portrait { width: 200px; height: 200px; }
  .band { padding: 56px 18px; }
  .talks li { grid-template-columns: 1fr; gap: 0; }
}
@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  .card { transition: none; }
}