:root {
  --bg: #0b1020;
  --bg-soft: #111834;
  --surface: #ffffff;
  --surface-alt: #f5f7fc;
  --ink: #0f1729;
  --ink-soft: #47506b;
  --ink-mute: #6b7490;
  --line: #e3e8f4;
  --brand: #4f46e5;
  --brand-2: #06b6d4;
  --brand-ink: #3730a3;
  --ok: #059669;
  --ok-bg: #d1fae5;
  --radius: 16px;
  --radius-sm: 10px;
  --shadow: 0 10px 30px -12px rgba(15, 23, 41, 0.25);
  --shadow-sm: 0 4px 14px -8px rgba(15, 23, 41, 0.3);
  --maxw: 1120px;
  --font-head: "Space Grotesk", "Inter", system-ui, sans-serif;
  --font-body: "Inter", system-ui, -apple-system, sans-serif;
}

* { box-sizing: border-box; }

html { scroll-behavior: smooth; scroll-padding-top: 84px; }

body {
  margin: 0;
  font-family: var(--font-body);
  color: var(--ink);
  background: var(--surface);
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
}

a { color: var(--brand); text-decoration: none; }
a:hover { text-decoration: underline; }

.container { max-width: var(--maxw); margin: 0 auto; padding: 0 24px; }

/* ===================== NAV ===================== */
.nav {
  position: sticky;
  top: 0;
  z-index: 50;
  background: rgba(11, 16, 32, 0.85);
  backdrop-filter: saturate(180%) blur(12px);
  border-bottom: 1px solid rgba(255, 255, 255, 0.08);
}
.nav__inner {
  max-width: var(--maxw);
  margin: 0 auto;
  padding: 14px 24px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
}
.nav__brand { display: flex; align-items: center; gap: 10px; text-decoration: none; }
.nav__logo {
  font-family: var(--font-head);
  font-weight: 700;
  font-size: 1.2rem;
  color: #fff;
  letter-spacing: -0.02em;
}
.nav__badge {
  font-size: 0.7rem;
  font-weight: 600;
  color: #c7d2fe;
  background: rgba(99, 102, 241, 0.2);
  border: 1px solid rgba(129, 140, 248, 0.35);
  padding: 3px 8px;
  border-radius: 999px;
  letter-spacing: 0.02em;
}
.nav__links { display: flex; gap: 22px; }
.nav__links a {
  color: #cbd5e1;
  font-size: 0.9rem;
  font-weight: 500;
  text-decoration: none;
  transition: color 0.15s ease;
}
.nav__links a:hover { color: #fff; }

.nav__toggle {
  display: none;
  flex-direction: column;
  gap: 5px;
  background: none;
  border: 0;
  cursor: pointer;
  padding: 6px;
}
.nav__toggle span {
  width: 24px;
  height: 2px;
  background: #e2e8f0;
  border-radius: 2px;
  transition: transform 0.2s ease, opacity 0.2s ease;
}

/* ===================== HERO ===================== */
.hero {
  position: relative;
  overflow: hidden;
  background: radial-gradient(1200px 500px at 80% -10%, #1e2a5a 0%, transparent 55%),
              radial-gradient(900px 500px at 0% 0%, #0e2a3a 0%, transparent 45%),
              var(--bg);
  color: #f8fafc;
  padding: 92px 0 96px;
}
.hero__bg {
  position: absolute;
  inset: 0;
  background-image:
    linear-gradient(rgba(255,255,255,0.035) 1px, transparent 1px),
    linear-gradient(90deg, rgba(255,255,255,0.035) 1px, transparent 1px);
  background-size: 48px 48px;
  mask-image: radial-gradient(700px 400px at 50% 20%, #000 40%, transparent 100%);
  pointer-events: none;
}
.hero__inner { position: relative; max-width: var(--maxw); margin: 0 auto; padding: 0 24px; }
.hero__eyebrow {
  font-weight: 600;
  color: #67e8f9;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  font-size: 0.8rem;
  margin: 0 0 14px;
}
.hero__title {
  font-family: var(--font-head);
  font-size: clamp(3rem, 8vw, 5.5rem);
  line-height: 1;
  margin: 0;
  font-weight: 700;
  letter-spacing: -0.03em;
  background: linear-gradient(120deg, #ffffff 20%, #a5b4fc 60%, #67e8f9 100%);
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
}
.hero__subtitle {
  font-family: var(--font-head);
  font-size: clamp(1.1rem, 2.5vw, 1.6rem);
  font-weight: 500;
  color: #e2e8f0;
  margin: 18px 0 0;
  max-width: 100%;
}
.hero__tagline {
  max-width: 900px;
  margin: 24px 0 0;
  padding-left: 18px;
  border-left: 3px solid var(--brand-2);
  color: #f1f5f9;
  font-family: var(--font-head);
  font-size: 1.12rem;
  font-weight: 600;
  line-height: 1.55;
}
.hero__lede {
  color: #a9b4cc;
  max-width: 100%;
  margin: 22px 0 0;
  font-size: 1.02rem;
}
.hero__meta {
  display: flex;
  flex-wrap: wrap;
  gap: 14px;
  margin: 36px 0 0;
}
.hero__meta-item {
  background: rgba(255, 255, 255, 0.05);
  border: 1px solid rgba(255, 255, 255, 0.12);
  border-radius: var(--radius-sm);
  padding: 12px 18px;
  min-width: 160px;
}
.hero__meta-label {
  display: block;
  font-size: 0.72rem;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: #7dd3fc;
  font-weight: 600;
}
.hero__meta-value { display: block; font-weight: 600; color: #f1f5f9; margin-top: 2px; }
.hero__cta { display: flex; flex-wrap: wrap; gap: 14px; margin-top: 36px; }

/* ===================== BUTTONS ===================== */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  font-weight: 600;
  font-size: 0.95rem;
  padding: 12px 22px;
  border-radius: 999px;
  text-decoration: none;
  transition: transform 0.12s ease, box-shadow 0.2s ease, background 0.2s ease;
  cursor: pointer;
  border: 1px solid transparent;
}
.btn:hover { text-decoration: none; transform: translateY(-1px); }
.btn--primary {
  background: linear-gradient(120deg, var(--brand), var(--brand-2));
  color: #fff;
  box-shadow: 0 10px 24px -10px rgba(79, 70, 229, 0.8);
}
.btn--ghost {
  background: rgba(255, 255, 255, 0.06);
  color: #e2e8f0;
  border-color: rgba(255, 255, 255, 0.2);
}

/* ===================== SECTIONS ===================== */
.section { padding: 84px 0; }
.section--alt { background: var(--surface-alt); }
.section__kicker {
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.1em;
  font-size: 0.78rem;
  color: var(--brand);
  margin: 0 0 10px;
}
.section__title {
  font-family: var(--font-head);
  font-size: clamp(1.7rem, 4vw, 2.5rem);
  font-weight: 700;
  letter-spacing: -0.02em;
  margin: 0 0 24px;
  color: var(--ink);
}
.section__intro { color: var(--ink-soft); max-width: 100%; font-size: 1.05rem; margin: 0 0 32px; }
.prose { max-width: 100%; color: var(--ink-soft); font-size: 1.05rem; }
.prose p { margin: 0 0 18px; }
.prose strong { color: var(--ink); }

/* ===================== CARDS ===================== */
.cards { display: grid; gap: 20px; margin-top: 44px; }
.cards--3 { grid-template-columns: repeat(3, 1fr); }
.card {
  background: var(--surface);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 24px;
  box-shadow: var(--shadow-sm);
}
.card--soft { background: linear-gradient(180deg, #ffffff, #fbfcff); }
.card__title { font-family: var(--font-head); font-size: 1.1rem; margin: 0 0 8px; color: var(--ink); }
.card p { margin: 0; color: var(--ink-soft); font-size: 0.97rem; }

/* ===================== TOPICS ===================== */
.research-questions {
  list-style: none;
  counter-reset: question;
  padding: 0;
  margin: 0;
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 14px;
}
.research-questions li {
  counter-increment: question;
  display: flex;
  gap: 16px;
  align-items: flex-start;
  background: var(--surface);
  border: 1px solid var(--line);
  border-radius: var(--radius-sm);
  padding: 18px 20px;
  color: var(--ink);
  font-weight: 500;
  box-shadow: var(--shadow-sm);
}
.research-questions li::before {
  content: counter(question, decimal-leading-zero);
  font-family: var(--font-head);
  font-weight: 700;
  color: var(--brand);
  font-size: 1.05rem;
  flex: none;
}
.scope-goal {
  margin: 32px 0 0;
  padding: 22px 24px;
  border-left: 4px solid var(--brand-2);
  background: var(--surface);
  color: var(--ink-soft);
  font-size: 1.05rem;
}
.topic-groups {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 20px;
}
.topic-group {
  background: var(--surface);
  border: 1px solid var(--line);
  border-radius: var(--radius-sm);
  padding: 22px 24px;
  box-shadow: var(--shadow-sm);
}
.topic-group h3 {
  font-family: var(--font-head);
  font-size: 1.08rem;
  margin: 0 0 12px;
  color: var(--ink);
}
.topic-group ul { margin: 0; padding-left: 20px; color: var(--ink-soft); }
.topic-group li { margin-bottom: 8px; }
.topic-group li:last-child { margin-bottom: 0; }
.cfp-topics { margin-top: 26px; }

/* ===================== CFP ===================== */
.prose h3 {
  font-family: var(--font-head);
  font-size: 1.25rem;
  color: var(--ink);
  margin: 30px 0 10px;
}
.cfp-details {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 1px;
  margin: 24px 0 36px;
  overflow: hidden;
  background: var(--line);
  border: 1px solid var(--line);
  border-radius: var(--radius-sm);
}
.cfp-details div { background: var(--surface); padding: 15px 18px; }
.cfp-details dt { color: var(--ink-mute); font-size: 0.78rem; font-weight: 700; text-transform: uppercase; }
.cfp-details dd { margin: 2px 0 0; color: var(--ink); font-weight: 600; }
.submission-formats {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 20px;
  margin-top: 26px;
}
.submission-intro { margin-top: 38px; }
.submission-intro h3 { margin-top: 0; }
.submission-format {
  border-left: 4px solid var(--brand);
  background: var(--surface-alt);
  padding: 22px 24px;
}
.submission-format h3 { font-family: var(--font-head); margin: 0 0 10px; font-size: 1.15rem; }
.submission-format p { margin: 0 0 12px; color: var(--ink-soft); }
.submission-format p:last-child { margin-bottom: 0; }
.submission-format strong { color: var(--ink); }
.cfp-guidelines { margin-top: 34px; }
.cfp-guidelines h3 { margin-top: 0; }
}

/* ===================== CALLOUT ===================== */
.callout {
  margin-top: 32px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 24px;
  flex-wrap: wrap;
  background: linear-gradient(120deg, #eef2ff, #ecfeff);
  border: 1px solid #dbe4ff;
  border-radius: var(--radius);
  padding: 26px 30px;
}
.callout__title { font-family: var(--font-head); margin: 0 0 4px; font-size: 1.2rem; color: var(--brand-ink); }
.callout p { margin: 0; color: var(--ink-soft); }

/* ===================== DATES ===================== */
.dates { display: grid; gap: 14px; }
.dates__item {
  display: grid;
  grid-template-columns: 220px 1fr;
  gap: 20px;
  align-items: center;
  background: var(--surface);
  border: 1px solid var(--line);
  border-left: 4px solid var(--brand);
  border-radius: var(--radius-sm);
  padding: 18px 22px;
  box-shadow: var(--shadow-sm);
}
.dates__item--highlight {
  border-left-color: var(--brand-2);
  background: linear-gradient(120deg, #ffffff, #ecfeff);
}
.dates__when { font-family: var(--font-head); font-weight: 700; color: var(--ink); }
.dates__what { color: var(--ink-soft); }
.dates__note { margin-top: 18px; color: var(--ink-mute); font-size: 0.9rem; }

/* ===================== SPEAKERS ===================== */
.speakers {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 20px;
}
.speaker {
  background: var(--surface);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 26px 22px;
  text-align: center;
  box-shadow: var(--shadow-sm);
  transition: transform 0.15s ease, box-shadow 0.2s ease;
}
.speaker:hover { transform: translateY(-4px); box-shadow: var(--shadow); }
.speaker__avatar,
.org__avatar {
  width: 96px;
  height: 96px;
  border-radius: 50%;
  margin: 0 auto 14px;
  display: grid;
  place-items: center;
  font-family: var(--font-head);
  font-weight: 700;
  font-size: 1.7rem;
  color: #fff;
  background: linear-gradient(135deg, var(--brand), var(--brand-2));
}
.speaker__avatar::after,
.org__avatar::after { content: attr(data-initials); }
.speaker__photo {
  width: 96px;
  height: 96px;
  border-radius: 50%;
  margin: 0 auto 14px;
  overflow: hidden;
  border: 3px solid #eef2ff;
  box-shadow: 0 6px 18px -10px rgba(15, 23, 41, 0.5);
}
.speaker__photo img { width: 100%; height: 100%; object-fit: cover; display: block; }
.speaker__name { font-family: var(--font-head); font-size: 1.05rem; margin: 0 0 2px; color: var(--ink); }
.speaker__affil { margin: 0 0 4px; color: var(--brand); font-weight: 600; font-size: 0.88rem; }
.speaker__note { margin: 0 0 14px; color: var(--ink-soft); font-size: 0.86rem; }

.speakers__group {
  font-family: var(--font-head);
  font-size: 1.15rem;
  font-weight: 600;
  color: var(--ink);
  margin: 8px 0 20px;
  padding-bottom: 8px;
  border-bottom: 2px solid var(--line);
}
.speakers + .speakers__group { margin-top: 48px; }
.speakers--keynote { grid-template-columns: repeat(4, 1fr); }
.speakers--keynote .speaker { grid-column: span 1; }

.tag {
  display: inline-block;
  font-size: 0.72rem;
  font-weight: 600;
  padding: 3px 10px;
  border-radius: 999px;
  background: #eef2ff;
  color: var(--brand-ink);
  border: 1px solid #dbe4ff;
}
.tag--ok { background: var(--ok-bg); color: var(--ok); border-color: #a7f3d0; }
.tag--sm { font-size: 0.66rem; padding: 2px 8px; }

/* ===================== SCHEDULE ===================== */
.schedule { display: grid; gap: 12px; }
.sched {
  display: grid;
  grid-template-columns: 150px 1fr;
  gap: 22px;
  background: var(--surface);
  border: 1px solid var(--line);
  border-radius: var(--radius-sm);
  padding: 18px 22px;
  box-shadow: var(--shadow-sm);
}
.sched__time { font-family: var(--font-head); font-weight: 700; color: var(--brand); font-size: 0.95rem; }
.sched__body h3 { margin: 0 0 4px; font-size: 1.02rem; color: var(--ink); font-family: var(--font-head); font-weight: 600; }
.sched__body p { margin: 0; color: var(--ink-soft); font-size: 0.92rem; }
.sched__panelists { margin-top: 6px !important; font-size: 0.86rem !important; }
.sched--break { background: var(--surface-alt); box-shadow: none; opacity: 0.85; }
.sched--break .sched__body h3 { color: var(--ink-mute); font-weight: 500; }
.special-session {
  display: grid;
  gap: 8px;
  padding: 12px;
  border: 1px solid #dbe4ff;
  border-radius: var(--radius);
  background: rgba(238, 242, 255, 0.45);
}
.sched--session-header {
  border-color: #c7d2fe;
  background: linear-gradient(120deg, #eef2ff, #ecfeff);
  box-shadow: none;
}
.sched--session-header .sched__time { color: var(--brand); }
.sched--session-header .sched__body h3 { color: var(--brand-ink); }
.sched--session-item { margin-left: 16px; }
.sched--feature {
  border-left: 4px solid var(--brand-2);
  background: linear-gradient(120deg, #ffffff, #f4f8ff);
}

/* ===================== ORGANIZERS ===================== */
.organizers {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 20px;
}
.org {
  display: flex;
  gap: 18px;
  align-items: center;
  background: var(--surface);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 22px;
  box-shadow: var(--shadow-sm);
}
.org__avatar { margin: 0; width: 60px; height: 60px; font-size: 1.15rem; flex: none; }
.org__name { font-family: var(--font-head); margin: 0 0 3px; font-size: 1.08rem; color: var(--ink); }
.org__affil { margin: 0 0 6px; color: var(--ink-soft); font-size: 0.9rem; }
.org__mail { font-size: 0.86rem; font-weight: 500; word-break: break-all; }

/* ===================== PC ===================== */
.pc {
  list-style: none;
  padding: 0;
  margin: 0;
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 10px;
}
.pc li {
  display: flex;
  flex-direction: column;
  background: var(--surface);
  border: 1px solid var(--line);
  border-radius: var(--radius-sm);
  padding: 14px 18px;
  box-shadow: var(--shadow-sm);
}
.pc__name { font-weight: 600; color: var(--ink); font-size: 0.97rem; }
.pc__affil { color: var(--ink-mute); font-size: 0.85rem; }

/* ===================== FOOTER ===================== */
.footer { background: var(--bg); color: #cbd5e1; padding: 54px 0 30px; }
.footer__inner {
  display: flex;
  justify-content: space-between;
  align-items: flex-start;
  gap: 28px;
  flex-wrap: wrap;
}
.footer__brand { font-family: var(--font-head); font-weight: 700; color: #fff; font-size: 1.2rem; margin: 0 0 6px; }
.footer__tag { margin: 0; color: #94a3b8; max-width: 420px; font-size: 0.92rem; }
.footer__links { display: flex; flex-wrap: wrap; gap: 18px; }
.footer__links a { color: #cbd5e1; font-size: 0.92rem; }
.footer__links a:hover { color: #fff; }
.footer__copy {
  max-width: var(--maxw);
  margin: 34px auto 0;
  padding: 22px 24px 0;
  border-top: 1px solid rgba(255, 255, 255, 0.1);
  color: #7c8aa5;
  font-size: 0.85rem;
}

/* ===================== RESPONSIVE ===================== */
@media (max-width: 900px) {
  .cards--3 { grid-template-columns: 1fr; }
  .research-questions { grid-template-columns: 1fr; }
  .topic-groups { grid-template-columns: 1fr; }
  .submission-formats { grid-template-columns: 1fr; }
  .speakers { grid-template-columns: repeat(2, 1fr); }
  .organizers { grid-template-columns: 1fr; }
  .pc { grid-template-columns: 1fr; }
}

@media (max-width: 720px) {
  .nav__links {
    position: absolute;
    top: 100%;
    left: 0;
    right: 0;
    flex-direction: column;
    gap: 0;
    background: var(--bg-soft);
    border-bottom: 1px solid rgba(255,255,255,0.1);
    padding: 8px 24px 16px;
    display: none;
  }
  .nav__links.is-open { display: flex; }
  .nav__links a { padding: 10px 0; border-bottom: 1px solid rgba(255,255,255,0.06); }
  .nav__toggle { display: flex; }
  .cfp-details { grid-template-columns: 1fr; }
  .dates__item { grid-template-columns: 1fr; gap: 6px; }
  .special-session { padding: 8px; }
  .sched--session-item { margin-left: 6px; }
  .sched { grid-template-columns: 1fr; gap: 6px; }
  .section { padding: 60px 0; }
  .hero { padding: 64px 0 72px; }
}

@media (max-width: 460px) {
  .speakers { grid-template-columns: 1fr; }
}