:root {
  --navy: #061d35;
  --navy-2: #0b2b4c;
  --blue: #4e79b7;
  --blue-dark: #3f669e;
  --paper: #ffffff;
  --soft: #f4f7fb;
  --ink: #061d35;
  --muted: #5f6f82;
  --line: rgba(6, 29, 53, 0.12);
  --shadow: 0 24px 80px rgba(6, 29, 53, 0.18);
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  margin: 0;
  color: var(--ink);
  font-family: Inter, ui-sans-serif, system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  background: var(--paper);
  line-height: 1.55;
}
a { color: inherit; text-decoration: none; }

.site-header {
  min-height: 104px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 30px;
  padding: 24px clamp(24px, 4.8vw, 64px);
  color: #fff;
  background: linear-gradient(90deg, #071c33 0%, #092542 60%, #0a2848 100%);
}
.brand img { display: block; width: min(360px, 38vw); height: auto; }
nav { display: flex; align-items: center; gap: clamp(18px, 2.8vw, 42px); text-transform: uppercase; font-size: 0.86rem; font-weight: 800; letter-spacing: .045em; }
nav a { opacity: .96; }
nav a:hover { opacity: 1; color: #dceaff; }
.nav-button { background: var(--blue); padding: 17px 28px; }
.nav-button:hover { color: #fff; background: var(--blue-dark); }

.hero {
  position: relative;
  min-height: 720px;
  color: #fff;
  display: flex;
  align-items: center;
  background-image: linear-gradient(90deg, rgba(7, 23, 42, .95) 0%, rgba(7, 23, 42, .72) 31%, rgba(7, 23, 42, .26) 62%, rgba(7, 23, 42, .04) 100%), url('assets/treehouse-hero.jpg');
  background-size: cover;
  background-position: center center;
}
.hero-content {
  width: min(1180px, calc(100% - 48px));
  margin: 0 auto;
  padding: 74px 0 54px;
}
.eyebrow { margin: 0 0 14px; color: #bcd3f1; text-transform: uppercase; font-size: .76rem; font-weight: 900; letter-spacing: .14em; }
.eyebrow.dark { color: var(--blue-dark); }
h1, h2, h3, p { margin-top: 0; }
h1 {
  margin: 0 0 22px;
  max-width: 640px;
  font-size: clamp(3.6rem, 7.2vw, 7.2rem);
  line-height: .98;
  letter-spacing: -.055em;
  text-transform: uppercase;
  font-weight: 850;
}
.hero-lede { max-width: 570px; margin-bottom: 25px; color: rgba(255,255,255,.93); font-size: clamp(1.25rem, 2vw, 1.75rem); line-height: 1.3; }
.accent-line { width: 64px; height: 4px; background: var(--blue); margin: 30px 0 34px; }
.event-details { display: grid; gap: 18px; margin-bottom: 34px; font-size: clamp(1rem, 1.6vw, 1.25rem); }
.event-row { display: grid; grid-template-columns: 42px 1fr; align-items: start; max-width: 600px; }
.event-icon { font-size: 1.75rem; line-height: 1; color: #fff; opacity: .94; }
.button { display: inline-flex; align-items: center; justify-content: center; border-radius: 0; padding: 18px 32px; font-size: .9rem; font-weight: 850; letter-spacing: .055em; text-transform: uppercase; transition: transform .2s ease, background .2s ease; }
.button:hover { transform: translateY(-2px); }
.button-primary { background: var(--blue); color: #fff; box-shadow: 0 12px 30px rgba(0,0,0,.18); }
.button-primary:hover { background: var(--blue-dark); }
.button-outline { border: 1px solid rgba(255,255,255,.78); color: #fff; }
.button-outline:hover { background: rgba(255,255,255,.1); }

.intro-section { display: grid; grid-template-columns: 300px 1fr; gap: 80px; padding: 50px clamp(24px, 6.5vw, 96px); align-items: start; background: #fff; }
.intro-title h2 { margin: 0; font-size: clamp(2rem, 3vw, 3rem); line-height: 1.08; letter-spacing: -.035em; color: var(--ink); }
.intro-copy p { max-width: 760px; margin: 0; font-size: clamp(1.15rem, 1.6vw, 1.45rem); line-height: 1.5; color: #121a24; }

.section { padding: 86px clamp(24px, 6vw, 84px); }
.centered { text-align: center; }
.section-lede { max-width: 720px; margin: 0 auto 50px; color: var(--muted); font-size: 1.1rem; }
h2 { font-size: clamp(2.1rem, 4vw, 3.7rem); line-height: 1.08; letter-spacing: -.04em; margin-bottom: 18px; }
h3 { font-size: .96rem; letter-spacing: .055em; text-transform: uppercase; }
.feature-grid { display: grid; grid-template-columns: repeat(4, 1fr); gap: 24px; max-width: 1120px; margin: 0 auto; }
.feature-card { padding: 28px 22px; border-right: 1px solid var(--line); }
.feature-card:last-child { border-right: 0; }
.feature-icon { color: var(--blue-dark); font-size: 2.7rem; margin-bottom: 16px; }
.feature-card p, .agenda-list p, .faq-grid p { color: var(--muted); font-size: .95rem; }

.split-section { display: grid; grid-template-columns: 1fr 1fr; background: var(--soft); }
.split-panel { padding: clamp(48px, 7vw, 90px); }
.light-panel { background: #fff; }
.check-list { list-style: none; padding: 0; margin: 24px 0 32px; }
.check-list li { margin: 10px 0; padding-left: 30px; position: relative; }
.check-list li::before { content: "✓"; position: absolute; left: 0; color: var(--blue-dark); font-weight: 900; }
.text-button { display: inline-flex; border: 1px solid var(--blue); color: var(--blue-dark); padding: 12px 18px; text-transform: uppercase; font-weight: 850; letter-spacing: .07em; font-size: .78rem; }
.agenda-panel { background: linear-gradient(135deg, #eef4fb, #fff); }
.agenda-list article { display: grid; grid-template-columns: 52px 1fr; gap: 18px; padding: 22px 0; border-bottom: 1px solid var(--line); }
.agenda-list span { width: 44px; height: 44px; border-radius: 999px; display: inline-flex; align-items: center; justify-content: center; background: var(--navy); color: #fff; font-weight: 900; font-size: .85rem; }
.agenda-list h3 { margin-bottom: 4px; }

.venue-section { padding: 76px clamp(24px, 7vw, 96px); color: #fff; background: linear-gradient(90deg, rgba(6,29,53,.95), rgba(6,29,53,.7)), url('assets/treehouse-hero.jpg') center center / cover no-repeat; }
.venue-section h2 { max-width: 900px; margin-bottom: 8px; }
.venue-section p:last-child { margin: 0; font-size: 1.2rem; color: rgba(255,255,255,.9); }

.sponsor-band { display: flex; align-items: center; justify-content: space-between; gap: 30px; padding: 58px clamp(24px, 7vw, 96px); color: #fff; background: linear-gradient(90deg, var(--navy), var(--navy-2)); }
.sponsor-band h2 { max-width: 780px; margin: 0; font-size: clamp(1.8rem, 3vw, 3rem); }
.faq-section { background: #fff; }
.faq-section > h2, .faq-section > .eyebrow { text-align: center; }
.faq-grid { max-width: 940px; margin: 38px auto 0; display: grid; gap: 14px; }
details { border: 1px solid var(--line); background: #fff; padding: 22px 24px; box-shadow: 0 8px 26px rgba(6,29,53,.05); }
summary { cursor: pointer; font-weight: 850; font-size: 1.05rem; }
details p { margin: 14px 0 0; }
.final-cta { display: flex; justify-content: space-between; align-items: center; gap: 32px; padding: 64px clamp(24px, 7vw, 96px); background: var(--soft); }
.final-cta h2 { max-width: 760px; margin-bottom: 10px; }
.final-cta p:last-child { color: var(--muted); margin-bottom: 0; }
.site-footer { display: flex; align-items: center; justify-content: space-between; gap: 20px; padding: 30px clamp(24px, 6vw, 72px); background: #041a30; color: rgba(255,255,255,.9); }
.site-footer img { width: min(320px, 56vw); height: auto; display: block; }
.site-footer a { font-weight: 800; }

@media (max-width: 980px) {
  .site-header { align-items: flex-start; }
  nav { display: none; }
  .brand img { width: min(330px, 72vw); }
  .hero { min-height: 680px; background-position: 60% center; }
  .intro-section { grid-template-columns: 1fr; gap: 24px; }
  .feature-grid { grid-template-columns: repeat(2, 1fr); }
  .feature-card { border-right: 0; border-bottom: 1px solid var(--line); }
  .split-section { grid-template-columns: 1fr; }
  .sponsor-band, .final-cta, .site-footer { flex-direction: column; align-items: flex-start; }
}
@media (max-width: 620px) {
  .site-header { min-height: 90px; padding: 22px; }
  .brand img { width: min(300px, 80vw); }
  .hero { min-height: 690px; background-position: 62% center; }
  .hero-content { width: min(100% - 36px, 1180px); padding: 54px 0; }
  h1 { font-size: 3.45rem; }
  .button { width: 100%; }
  .section { padding: 64px 22px; }
  .intro-section, .split-panel, .sponsor-band, .final-cta, .venue-section { padding: 52px 24px; }
  .feature-grid { grid-template-columns: 1fr; }
}