:root {
  --bg: #ffffff;
  --bg-soft: #f4f7fd;
  --card: #ffffff;
  --text: #16203a;
  --muted: #5a6b8c;
  --brand: #264CC8;
  --brand-2: #4f74e0;
  --accent: #264CC8;
  --border: #e2e8f5;
  --radius: 14px;
  --shadow: 0 10px 30px rgba(38, 76, 200, .12);
  --max: 1120px;
}

* { box-sizing: border-box; }

html { scroll-behavior: smooth; }

body {
  margin: 0;
  font-family: "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
  color: var(--text);
  background: var(--bg);
  line-height: 1.6;
}

a { color: var(--brand); text-decoration: none; }
a:hover { color: var(--brand-2); }

img { max-width: 100%; display: block; }

.container { width: 100%; max-width: var(--max); margin: 0 auto; padding: 0 20px; }

/* Header / Nav */
.site-header {
  position: sticky; top: 0; z-index: 50;
  background: rgba(255, 255, 255, .9);
  backdrop-filter: blur(10px);
  border-bottom: 1px solid var(--border);
}
.nav { display: flex; align-items: center; justify-content: space-between; height: 66px; }
.brand { display: flex; align-items: center; gap: 10px; font-weight: 800; letter-spacing: .3px; color: var(--text); }
.brand .logo {
  width: 34px; height: 34px; border-radius: 9px;
  background: linear-gradient(135deg, var(--brand), var(--brand-2));
  display: grid; place-items: center; font-size: 15px; color: #ffffff; font-weight: 900;
}
.nav-links { display: flex; align-items: center; gap: 20px; list-style: none; margin: 0; padding: 0; }
.nav-links a { color: var(--muted); font-weight: 600; }
.nav-links a:hover, .nav-links a.active { color: var(--text); }
.nav-toggle { display: none; background: none; border: 1px solid var(--border); color: var(--text); border-radius: 8px; padding: 8px 10px; cursor: pointer; }

.btn {
  display: inline-block; padding: 11px 20px; border-radius: 999px; font-weight: 700;
  background: linear-gradient(135deg, var(--brand), var(--brand-2)); color: #ffffff !important;
  border: none; cursor: pointer; transition: transform .15s ease, box-shadow .15s ease;
}
.btn:hover { transform: translateY(-2px); box-shadow: var(--shadow); color: #ffffff !important; }
.btn.ghost { background: transparent; color: var(--text) !important; border: 1px solid var(--border); }

/* Sections */
section { padding: 78px 0; }
.section-head { text-align: center; max-width: 720px; margin: 0 auto 44px; }
.eyebrow { text-transform: uppercase; letter-spacing: 3px; font-size: 12px; color: var(--brand-2); font-weight: 800; }
h1, h2, h3 { line-height: 1.2; margin: 0 0 12px; }
h2 { font-size: clamp(26px, 4vw, 40px); }
.muted { color: var(--muted); }

/* Hero */
.hero {
  position: relative; padding: 96px 0 88px;
  background:
    radial-gradient(1000px 500px at 80% -10%, rgba(38,76,200,.12), transparent),
    radial-gradient(900px 500px at 0% 20%, rgba(79,116,224,.10), transparent),
    var(--bg-soft);
  border-bottom: 1px solid var(--border);
}
.hero .eyebrow { font-size: 16px; letter-spacing: 4px; }
.hero h1 { font-size: clamp(34px, 6vw, 58px); line-height: 1.1; }
.hero .hero-sub { font-size: clamp(17px, 2.2vw, 22px); font-weight: 700; color: var(--brand); max-width: 760px; margin: 32px 0 12px; }
.hero-meta { display: flex; flex-wrap: wrap; gap: 16px; margin: 26px 0 32px; }
.meta-pill { display: flex; align-items: center; gap: 8px; background: var(--card); border: 1px solid var(--border); padding: 10px 16px; border-radius: 999px; font-weight: 600; box-shadow: 0 4px 14px rgba(38,76,200,.06); }
.hero-actions { display: flex; gap: 14px; flex-wrap: wrap; }

/* Stats */
.stats { display: grid; grid-template-columns: repeat(4, 1fr); gap: 18px; margin-top: 54px; }
.stat { background: var(--card); border: 1px solid var(--border); border-radius: var(--radius); padding: 22px; text-align: center; box-shadow: 0 6px 20px rgba(38,76,200,.06); }
.stat .num { font-size: 30px; font-weight: 800; color: var(--brand); }
.stat .label { color: var(--muted); font-size: 14px; }

/* Cards grid */
.grid { display: grid; gap: 22px; }
.grid.cols-3 { grid-template-columns: repeat(3, 1fr); }
.grid.cols-4 { grid-template-columns: repeat(4, 1fr); }

.card { background: var(--card); border: 1px solid var(--border); border-radius: var(--radius); overflow: hidden; box-shadow: 0 6px 20px rgba(38,76,200,.06); }

/* Speakers */
.speaker { text-align: center; padding-bottom: 20px; transition: transform .15s ease, border-color .15s ease; }
.speaker:hover { transform: translateY(-4px); border-color: var(--brand); }
.speaker .avatar { width: 100%; aspect-ratio: 1/1; object-fit: cover; background: var(--bg-soft); }
.speaker h3 { margin: 16px 0 2px; font-size: 18px; padding: 0 8px; }
.speaker .role { color: var(--brand-2); font-weight: 600; font-size: 14px; padding: 0 8px; }
.speaker .title { color: var(--muted); font-size: 13px; padding: 0 8px; }

/* Sponsors */
.sponsor-tier { margin-bottom: 40px; }
.sponsor-tier h3 { text-align: center; color: var(--muted); text-transform: uppercase; letter-spacing: 2px; font-size: 14px; }
.sponsor-logos { display: flex; flex-wrap: wrap; justify-content: center; gap: 18px; }
.sponsor {
  background: var(--card); border: 1px solid var(--border); border-radius: var(--radius);
  padding: 22px 30px; font-weight: 800; letter-spacing: .5px; color: var(--text);
  display: grid; place-items: center; min-width: 180px; min-height: 84px;
}
.sponsor.platinum { min-width: 240px; min-height: 110px; font-size: 22px; }
.sponsor.gold { min-width: 200px; min-height: 96px; font-size: 19px; }

/* Registration fees */
.fees { display: grid; grid-template-columns: repeat(2, 1fr); gap: 18px; max-width: 640px; margin: 0 auto 26px; }
.fee { padding: 24px; }
.fee-type { font-weight: 700; }
.fee-who { color: var(--muted); font-size: 14px; }
.fee-price { font-size: 34px; font-weight: 800; color: var(--brand); margin-top: 8px; }

/* About */
.about-head { margin: 0 auto 32px; }
.about-grid { display: grid; grid-template-columns: 1.2fr 1fr; gap: 34px; align-items: center; }
.about-list { list-style: none; padding: 0; margin: 18px 0 0; display: grid; gap: 12px; }
.about-list li { display: flex; gap: 12px; }
.about-list .tick { color: var(--brand-2); font-weight: 900; }

/* Program */
.day-tabs { display: flex; justify-content: center; gap: 10px; flex-wrap: wrap; margin-bottom: 34px; }
.day-tab { background: var(--card); border: 1px solid var(--border); color: var(--muted); padding: 12px 20px; border-radius: 999px; cursor: pointer; font-weight: 700; }
.day-tab.active { background: linear-gradient(135deg, var(--brand), var(--brand-2)); color: #ffffff; border-color: transparent; }
.day-panel { display: none; }
.day-panel.active { display: block; }
.period { display: flex; align-items: center; gap: 14px; margin: 38px 0 16px; color: var(--brand); font-weight: 800; text-transform: uppercase; letter-spacing: 3px; font-size: 13px; }
.period::after { content: ""; flex: 1; height: 1px; background: var(--border); }
.day-panel > .period:first-child { margin-top: 0; }

.block { border: 1px solid var(--border); border-radius: var(--radius); background: var(--card); margin-bottom: 14px; overflow: hidden; box-shadow: 0 4px 14px rgba(38,76,200,.05); }
.block-head { padding: 18px 20px; background: var(--bg-soft); border-bottom: 1px solid var(--border); }
.block-head h3 { font-size: 20px; margin: 0; }
.block-head .meta { color: var(--muted); font-size: 14px; margin-top: 4px; }

.talk { display: grid; grid-template-columns: 130px 1fr; gap: 20px; padding: 16px 20px; border-top: 1px solid var(--border); }
.talk:first-child, .block-head + .talk, .sub-head + .talk { border-top: none; }
.talk .time { color: var(--brand); font-weight: 800; white-space: nowrap; font-variant-numeric: tabular-nums; }
.talk .title { font-weight: 700; }
.talk .who { margin-top: 6px; color: var(--muted); font-size: 14px; }
.talk .who strong { color: var(--text); }
.talk.break { background: var(--bg-soft); }
.talk.break .title { color: var(--muted); font-weight: 600; }

/* Parallel tracks */
.parallel-note { display: flex; align-items: center; flex-wrap: wrap; gap: 10px; padding: 12px 16px; margin-bottom: 16px; border: 1px dashed var(--brand-2); border-radius: var(--radius); background: rgba(38,76,200,.05); font-weight: 600; font-size: 14px; }
.parallel-note .badge { background: var(--brand); color: #ffffff; border-radius: 999px; padding: 2px 10px; font-size: 11px; font-weight: 800; letter-spacing: 1px; text-transform: uppercase; }
.tracks { display: grid; grid-template-columns: 1.2fr 1fr; gap: 16px; align-items: start; margin-bottom: 14px; }
.track-stack { display: grid; gap: 16px; }
.track { --track: var(--brand); border: 1px solid var(--border); border-top: 4px solid var(--track); border-radius: var(--radius); background: var(--card); overflow: hidden; box-shadow: 0 4px 14px rgba(38,76,200,.05); }
.track.t-b { --track: #0f9d8a; }
.track.t-c { --track: #8a4fd8; }
.track.t-d { --track: #e0761f; }
.track-head { padding: 16px 18px; border-bottom: 1px solid var(--border); }
.track-label { display: inline-block; font-size: 11px; font-weight: 800; letter-spacing: 1px; text-transform: uppercase; color: #ffffff; background: var(--track); padding: 3px 10px; border-radius: 999px; margin-bottom: 8px; }
.track-head h3 { font-size: 17px; margin: 0 0 4px; }
.track-head .meta, .sub-head .meta { color: var(--muted); font-size: 13px; font-weight: 400; }
.sub-head { padding: 12px 18px; background: var(--bg-soft); border-top: 1px solid var(--border); border-bottom: 1px solid var(--border); font-weight: 700; font-size: 15px; }
.track-head + .sub-head { border-top: none; }
.track .talk { grid-template-columns: 1fr; gap: 2px; padding: 12px 18px; }
.track .talk .time { color: var(--track); font-size: 13px; }
.track .talk .title { font-size: 15px; }
.track .empty { padding: 14px 18px; color: var(--muted); font-size: 14px; font-style: italic; }

.tag { display: inline-block; font-size: 11px; font-weight: 800; text-transform: uppercase; letter-spacing: 1px; padding: 3px 10px; border-radius: 999px; background: rgba(38,76,200,.08); color: var(--brand); border: 1px solid var(--border); margin-bottom: 8px; }

/* Footer */
.site-footer { border-top: 1px solid var(--border); background: var(--bg-soft); padding: 40px 0; margin-top: 20px; }
.footer-grid { display: flex; justify-content: space-between; flex-wrap: wrap; gap: 24px; align-items: center; }
.footer-grid .muted { max-width: 420px; }

@media (max-width: 900px) {
  .stats { grid-template-columns: repeat(2, 1fr); }
  .grid.cols-3, .grid.cols-4 { grid-template-columns: repeat(2, 1fr); }
  .about-grid { grid-template-columns: 1fr; }
  .tracks { grid-template-columns: 1fr; }
  .nav-links { position: absolute; top: 66px; left: 0; right: 0; background: var(--bg-soft); flex-direction: column; gap: 0; border-bottom: 1px solid var(--border); display: none; }
  .nav-links.open { display: flex; }
  .nav-links li { width: 100%; text-align: center; padding: 14px 0; border-top: 1px solid var(--border); }
  .nav-toggle { display: inline-block; }
}
@media (max-width: 640px) {
  .grid.cols-3, .grid.cols-4 { grid-template-columns: 1fr; }
  .fees { grid-template-columns: 1fr; }
  .talk { grid-template-columns: 1fr; gap: 4px; }
}