/* ============================================================
   QC4PDE — Quantum Computing for PDEs Workshop
   Stylesheet
   Aesthetic: editorial-academic, restrained, with scientific
   texture. Dark ink on warm paper, with a single accent.
   ============================================================ */

/* ---------- Fonts ---------- */
@import url('https://fonts.googleapis.com/css2?family=Fraunces:opsz,wght@9..144,400;9..144,500;9..144,600;9..144,700&family=Inter:wght@400;500;600&family=JetBrains+Mono:wght@400;500&display=swap');

/* ---------- Tokens ---------- */
:root {
  --paper: #f7f4ed;
  --paper-deep: #efeae0;
  --ink: #1a1f2e;
  --ink-soft: #3a4255;
  --ink-mute: #6b7184;
  --rule: #d9d2c2;
  --accent: #b3401f;        /* warm rust — distinct from "quantum purple" */
  --accent-soft: #d97550;
  --highlight: #f0e2c4;     /* used for subtle background blocks */
  --max: 1100px;
  --gutter: clamp(1rem, 4vw, 2.5rem);
}

* { box-sizing: border-box; }

html { scroll-behavior: smooth; }

body {
  margin: 0;
  background: var(--paper);
  color: var(--ink);
  font-family: 'Inter', -apple-system, system-ui, sans-serif;
  font-size: 17px;
  line-height: 1.65;
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
}

/* Subtle paper texture using SVG noise */
body::before {
  content: '';
  position: fixed;
  inset: 0;
  pointer-events: none;
  background-image: url("data:image/svg+xml;utf8,<svg xmlns='http://www.w3.org/2000/svg' width='200' height='200'><filter id='n'><feTurbulence type='fractalNoise' baseFrequency='0.85' numOctaves='2'/><feColorMatrix values='0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0.04 0'/></filter><rect width='100%' height='100%' filter='url(%23n)'/></svg>");
  opacity: 0.6;
  z-index: 0;
  mix-blend-mode: multiply;
}

main, header, footer, nav { position: relative; z-index: 1; }

/* ---------- Typography ---------- */
h1, h2, h3, h4 {
  font-family: 'Fraunces', Georgia, serif;
  font-weight: 600;
  letter-spacing: -0.01em;
  line-height: 1.15;
  margin: 0 0 0.6em;
  color: var(--ink);
}

h1 {
  font-size: clamp(2.4rem, 5.5vw, 4rem);
  font-weight: 500;
  letter-spacing: -0.025em;
  line-height: 1.05;
}

h2 {
  font-size: clamp(1.6rem, 3vw, 2.25rem);
  font-weight: 500;
}

h3 {
  font-size: 1.25rem;
  font-weight: 600;
}

h4 {
  font-size: 1rem;
  font-family: 'Inter', sans-serif;
  font-weight: 600;
  letter-spacing: 0.04em;
  text-transform: uppercase;
  color: var(--ink-soft);
}

p { margin: 0 0 1.1em; }

a {
  color: var(--accent);
  text-decoration: none;
  border-bottom: 1px solid transparent;
  transition: border-color 0.15s ease, color 0.15s ease;
}

a:hover {
  color: var(--ink);
  border-bottom-color: var(--accent);
}

code, .mono {
  font-family: 'JetBrains Mono', ui-monospace, Menlo, monospace;
  font-size: 0.9em;
}

.eyebrow {
  font-family: 'JetBrains Mono', monospace;
  font-size: 0.78rem;
  text-transform: uppercase;
  letter-spacing: 0.18em;
  color: var(--accent);
  margin-bottom: 1.5rem;
  display: inline-block;
}

/* ---------- Layout ---------- */
.wrap {
  max-width: var(--max);
  margin: 0 auto;
  padding: 0 var(--gutter);
}

section {
  padding: 5rem 0;
  border-top: 1px solid var(--rule);
}

section:first-of-type { border-top: none; }

/* ---------- Header / Nav ---------- */
header.site-header {
  padding: 1.5rem 0;
  border-bottom: 1px solid var(--rule);
  background: var(--paper);
  position: sticky;
  top: 0;
  z-index: 50;
  backdrop-filter: blur(8px);
  background: rgba(247, 244, 237, 0.92);
}

header.site-header .wrap {
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 2rem;
}

.brand {
  font-family: 'Fraunces', serif;
  font-size: 1.25rem;
  font-weight: 600;
  color: var(--ink);
  border: none;
  letter-spacing: -0.01em;
}

.brand:hover { color: var(--accent); border: none; }

.brand .brand-mark {
  display: inline-block;
  width: 0.55em;
  height: 0.55em;
  background: var(--accent);
  border-radius: 50%;
  margin-right: 0.5em;
  vertical-align: 0.1em;
}

nav.primary {
  display: flex;
  gap: 1.75rem;
  flex-wrap: wrap;
}

nav.primary a {
  color: var(--ink-soft);
  font-size: 0.92rem;
  font-weight: 500;
  border: none;
}

nav.primary a:hover { color: var(--accent); border: none; }

nav.primary a.current {
  color: var(--ink);
  border-bottom: 1.5px solid var(--accent);
  padding-bottom: 2px;
}

/* ---------- Hero ---------- */
.hero {
  padding: 6rem 0 4rem;
  position: relative;
  overflow: hidden;
  border-top: none;
}

.hero .wrap {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 2rem;
  position: relative;
}

.hero-meta {
  display: flex;
  flex-wrap: wrap;
  gap: 1.25rem 2rem;
  margin-top: 2.25rem;
  padding-top: 2rem;
  border-top: 1px solid var(--rule);
  font-size: 0.92rem;
}

.hero-meta div {
  display: flex;
  flex-direction: column;
  gap: 0.25rem;
}

.hero-meta .label {
  font-family: 'JetBrains Mono', monospace;
  font-size: 0.72rem;
  text-transform: uppercase;
  letter-spacing: 0.15em;
  color: var(--ink-mute);
}

.hero-meta .value { color: var(--ink); font-weight: 500; }

.hero-deck {
  font-family: 'Fraunces', serif;
  font-style: italic;
  font-size: clamp(1.15rem, 1.8vw, 1.4rem);
  line-height: 1.5;
  color: var(--ink-soft);
  max-width: 42em;
  margin-top: 1.5rem;
}

/* PDE wave decoration in hero */
.hero-wave {
  position: absolute;
  right: -5%;
  top: 30%;
  width: 60%;
  max-width: 700px;
  opacity: 0.12;
  pointer-events: none;
  z-index: 0;
}

/* ---------- CTA buttons ---------- */
.cta-row {
  display: flex;
  flex-wrap: wrap;
  gap: 0.75rem;
  margin-top: 2rem;
}

.btn {
  display: inline-block;
  padding: 0.75rem 1.4rem;
  font-size: 0.95rem;
  font-weight: 500;
  border: 1px solid var(--ink);
  border-radius: 0;
  background: var(--ink);
  color: var(--paper);
  cursor: pointer;
  transition: background 0.15s, color 0.15s;
}

.btn:hover {
  background: var(--accent);
  border-color: var(--accent);
  color: var(--paper);
}

.btn-outline {
  background: transparent;
  color: var(--ink);
}

.btn-outline:hover {
  background: var(--ink);
  color: var(--paper);
  border-color: var(--ink);
}

/* ---------- Topic columns ---------- */
.topic-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
  gap: 2.5rem;
  margin-top: 3rem;
}

.topic h3 {
  border-top: 2px solid var(--ink);
  padding-top: 1rem;
  margin-bottom: 1rem;
}

.topic ul {
  list-style: none;
  padding: 0;
  margin: 0;
  font-size: 0.95rem;
  color: var(--ink-soft);
}

.topic li {
  padding: 0.4rem 0;
  border-bottom: 1px dotted var(--rule);
}

.topic li:last-child { border-bottom: none; }

/* ---------- Dates table ---------- */
.dates {
  margin-top: 2.5rem;
  border-top: 2px solid var(--ink);
}

.dates .row {
  display: grid;
  grid-template-columns: 1fr auto;
  gap: 1rem;
  padding: 1rem 0;
  border-bottom: 1px solid var(--rule);
  align-items: baseline;
}

.dates .row.upcoming { background: linear-gradient(90deg, var(--highlight) 0%, transparent 50%); padding-left: 1rem; margin-left: -1rem; }

.dates .label { color: var(--ink); }
.dates .date { font-family: 'JetBrains Mono', monospace; font-size: 0.92rem; color: var(--ink-soft); white-space: nowrap; }
.dates .row.passed .label,
.dates .row.passed .date { color: var(--ink-mute); text-decoration: line-through; text-decoration-thickness: 1px; }

.tz-note {
  font-size: 0.85rem;
  color: var(--ink-mute);
  margin-top: 1rem;
  font-style: italic;
}

/* ---------- People grid (organizers, speakers) ---------- */
.people {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(220px, 1fr));
  gap: 2.5rem 2rem;
  margin-top: 3rem;
}

.person {
  display: flex;
  flex-direction: column;
}

/* .person .photo {
  width: 100%;
  aspect-ratio: 1 / 1;
  object-fit: cover;
  margin-bottom: 1rem;
  background: var(--paper-deep);
  filter: grayscale(20%) contrast(0.95);
  transition: filter 0.3s ease;
} */

.person .photo {
  width: 100%;
  max-width: 160px;
  height: auto;
  margin-bottom: 1rem;
  background: var(--paper-deep);
  border: 1px solid var(--rule);
  display: block;
}

.person:hover .photo {
  filter: grayscale(0%) contrast(1);
}

.person .name {
  font-family: 'Fraunces', serif;
  font-size: 1.1rem;
  font-weight: 600;
  margin-bottom: 0.2rem;
  color: var(--ink);
}

.person .affil {
  font-size: 0.88rem;
  color: var(--ink-soft);
  line-height: 1.4;
}

.person .role {
  font-family: 'JetBrains Mono', monospace;
  font-size: 0.72rem;
  text-transform: uppercase;
  letter-spacing: 0.12em;
  color: var(--accent);
  margin-bottom: 0.5rem;
}

.person a { font-size: 0.85rem; }

/* ---------- Speaker list (compact) ---------- */
.speaker-list {
  list-style: none;
  padding: 0;
  margin: 2rem 0 0;
  columns: 2;
  column-gap: 3rem;
}

.speaker-list li {
  break-inside: avoid;
  padding: 0.6rem 0;
  border-bottom: 1px dotted var(--rule);
  font-size: 0.95rem;
}

.speaker-list .sp-name { font-weight: 500; color: var(--ink); }
.speaker-list .sp-affil { color: var(--ink-mute); font-size: 0.85rem; }

@media (max-width: 600px) { .speaker-list { columns: 1; } }

/* ---------- Program / agenda ---------- */
.program {
  margin-top: 2.5rem;
}

.session {
  border-top: 2px solid var(--ink);
  padding: 1.5rem 0 2rem;
}

.session-head {
  display: flex;
  justify-content: space-between;
  align-items: baseline;
  flex-wrap: wrap;
  gap: 1rem;
  margin-bottom: 1rem;
}

.session-title {
  font-family: 'Fraunces', serif;
  font-size: 1.3rem;
  font-weight: 600;
}

.session-time {
  font-family: 'JetBrains Mono', monospace;
  font-size: 0.85rem;
  color: var(--ink-mute);
}

.slot {
  display: grid;
  grid-template-columns: 90px 1fr;
  gap: 1.5rem;
  padding: 0.75rem 0;
  border-bottom: 1px dotted var(--rule);
  font-size: 0.95rem;
}

.slot:last-child { border-bottom: none; }

.slot .t {
  font-family: 'JetBrains Mono', monospace;
  font-size: 0.82rem;
  color: var(--ink-mute);
  padding-top: 0.1rem;
}

.slot .desc strong { color: var(--ink); font-weight: 500; display: block; margin-bottom: 0.1rem; }
.slot .desc em { color: var(--ink-soft); font-style: normal; font-size: 0.88rem; }

/* ---------- Callout ---------- */
.callout {
  background: var(--paper-deep);
  border-left: 3px solid var(--accent);
  padding: 1.5rem 1.75rem;
  margin: 2.5rem 0;
  font-size: 0.97rem;
}

.callout p:last-child { margin-bottom: 0; }

/* ---------- Editions list (homepage) ---------- */
.editions {
  display: grid;
  gap: 1rem;
  margin-top: 2rem;
}

.edition {
  display: grid;
  grid-template-columns: auto 1fr auto;
  gap: 1.5rem;
  padding: 1.5rem 0;
  border-top: 1px solid var(--rule);
  align-items: baseline;
}

.edition:last-child { border-bottom: 1px solid var(--rule); }

.edition .yr {
  font-family: 'Fraunces', serif;
  font-size: 2rem;
  font-weight: 500;
  line-height: 1;
  color: var(--ink);
}

.edition .ed-meta { color: var(--ink-soft); font-size: 0.95rem; }
.edition .ed-meta strong { color: var(--ink); font-weight: 500; }

.edition .status {
  font-family: 'JetBrains Mono', monospace;
  font-size: 0.72rem;
  text-transform: uppercase;
  letter-spacing: 0.12em;
  padding: 0.25rem 0.6rem;
  border: 1px solid var(--rule);
  white-space: nowrap;
}

.edition .status.live { background: var(--accent); border-color: var(--accent); color: var(--paper); }
.edition .status.upcoming { background: transparent; color: var(--accent); border-color: var(--accent); }
.edition .status.archived { color: var(--ink-mute); }

/* ---------- Two column intro ---------- */
.two-col {
  display: grid;
  grid-template-columns: 1fr 2fr;
  gap: 3rem;
  margin-top: 1rem;
}

@media (max-width: 760px) { .two-col { grid-template-columns: 1fr; gap: 1rem; } }

/* ---------- Footer ---------- */
footer.site-footer {
  margin-top: 4rem;
  padding: 3rem 0 2rem;
  border-top: 1px solid var(--rule);
  background: var(--paper-deep);
  font-size: 0.88rem;
  color: var(--ink-soft);
}

footer .foot-grid {
  display: grid;
  grid-template-columns: 2fr 1fr 1fr;
  gap: 2.5rem;
}

@media (max-width: 700px) { footer .foot-grid { grid-template-columns: 1fr; gap: 1.5rem; } }

footer h4 {
  margin-bottom: 0.75rem;
}

footer ul {
  list-style: none;
  padding: 0;
  margin: 0;
}

footer ul li { padding: 0.2rem 0; }

footer .copyright {
  margin-top: 2.5rem;
  padding-top: 1.5rem;
  border-top: 1px solid var(--rule);
  display: flex;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 1rem;
  font-size: 0.82rem;
  color: var(--ink-mute);
}

/* ---------- Misc ---------- */
.lead {
  font-size: 1.1rem;
  color: var(--ink-soft);
  max-width: 38em;
}

hr.rule {
  border: none;
  border-top: 1px solid var(--rule);
  margin: 3rem 0;
}

/* ---------- Subtle entrance animation ---------- */
@media (prefers-reduced-motion: no-preference) {
  .hero h1, .hero .eyebrow, .hero .hero-deck, .hero .cta-row, .hero-meta {
    animation: rise 0.7s ease-out backwards;
  }
  .hero .eyebrow    { animation-delay: 0.05s; }
  .hero h1          { animation-delay: 0.15s; }
  .hero .hero-deck  { animation-delay: 0.30s; }
  .hero .cta-row    { animation-delay: 0.45s; }
  .hero-meta        { animation-delay: 0.55s; }

  @keyframes rise {
    from { opacity: 0; transform: translateY(12px); }
    to   { opacity: 1; transform: translateY(0); }
  }
}