/* ==========================================================================
   2026 SEA Summit · Conference Site
   Mobile-first, single-page, no framework. Designed for Cloudflare Pages.
   ========================================================================== */

:root {
  --navy-900: #061a36;
  --navy-800: #0a2540;
  --navy-700: #0f3a66;
  --blue-500: #2470d6;
  --blue-400: #3a8eef;
  --cyan-300: #6dd3ff;
  --gold-400: #f3c875;
  --ink-900: #0f1d33;
  --ink-700: #2b3b54;
  --ink-500: #5b6a82;
  --ink-300: #97a2b5;
  --line: #e6ebf3;
  --bg-soft: #f4f7fc;
  --white: #ffffff;
  --radius: 14px;
  --radius-lg: 20px;
  --shadow-sm: 0 1px 3px rgba(8, 22, 50, 0.06);
  --shadow-md: 0 8px 24px rgba(8, 22, 50, 0.10);
  --shadow-lg: 0 18px 50px rgba(8, 22, 50, 0.18);
  --maxw: 960px;
}

/* Reset --------------------------------------------------------- */
*, *::before, *::after { box-sizing: border-box; }
html { -webkit-text-size-adjust: 100%; scroll-behavior: smooth; }
section[id] { scroll-margin-top: 70px; }
#top { scroll-margin-top: 0; }
body {
  margin: 0;
  font-family: -apple-system, BlinkMacSystemFont, "PingFang SC",
               "Hiragino Sans GB", "Microsoft YaHei", "Helvetica Neue",
               Helvetica, Arial, sans-serif;
  font-size: 16px;
  line-height: 1.6;
  color: var(--ink-900);
  background: var(--white);
  -webkit-font-smoothing: antialiased;
}
img { max-width: 100%; height: auto; display: block; }
ol, ul { list-style: none; padding: 0; margin: 0; }
a { color: inherit; text-decoration: none; }
h1, h2, h3, h4 { margin: 0; font-weight: 700; letter-spacing: -0.01em; }
p { margin: 0; }

/* Organizer / sponsor strip ------------------------------------ */
.org-strip {
  background: #ffffff;
  border-bottom: 1px solid var(--line);
  display: flex;
  justify-content: center;
  padding: 8px 12px;
}
.org-strip img {
  width: 100%;
  max-width: 800px;
  height: auto;
  display: block;
}

/* Header -------------------------------------------------------- */
.site-header {
  position: sticky;
  top: 0;
  z-index: 50;
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 12px 18px;
  background: rgba(6, 26, 54, 0.92);
  backdrop-filter: saturate(140%) blur(10px);
  -webkit-backdrop-filter: saturate(140%) blur(10px);
  color: var(--white);
}
.brand {
  display: flex;
  flex-direction: column;
  justify-content: center;
  line-height: 1.15;
  min-height: 44px;
  padding: 4px 4px 4px 0;
}
.brand-zh { font-weight: 700; font-size: 15px; }
.brand-en {
  font-size: 10px;
  letter-spacing: 0.2em;
  color: var(--cyan-300);
  text-transform: uppercase;
}
.nav { display: flex; gap: 6px; align-items: center; font-size: 14px; }
.nav a {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 44px;
  padding: 0 10px;
  opacity: 0.85;
}
.nav a:hover, .nav a:focus { opacity: 1; }
.nav-cta {
  background: var(--gold-400);
  color: var(--navy-900) !important;
  padding: 0 16px !important;
  border-radius: 999px;
  font-weight: 600;
  opacity: 1 !important;
}

/* Hero ---------------------------------------------------------- */
.hero {
  position: relative;
  overflow: hidden;
  color: var(--white);
  background:
    radial-gradient(ellipse at top right, rgba(109, 211, 255, 0.30), transparent 60%),
    radial-gradient(ellipse at bottom left, rgba(36, 112, 214, 0.35), transparent 55%),
    linear-gradient(160deg, var(--navy-900) 0%, var(--navy-800) 55%, var(--navy-700) 100%);
}
.hero-inner {
  max-width: var(--maxw);
  margin: 0 auto;
  padding: 56px 22px 80px;
  position: relative;
  z-index: 2;
}
.eyebrow {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  font-size: 11px;
  letter-spacing: 0.28em;
  color: var(--cyan-300);
  font-weight: 600;
  margin-bottom: 18px;
  text-transform: uppercase;
}
.eyebrow .dot {
  width: 6px; height: 6px;
  border-radius: 50%;
  background: var(--gold-400);
  box-shadow: 0 0 10px rgba(243, 200, 117, 0.7);
}
.hero-title {
  font-size: clamp(28px, 7vw, 44px);
  line-height: 1.18;
  margin-bottom: 14px;
}
.hero-subtitle {
  font-size: clamp(15px, 3.6vw, 18px);
  color: rgba(255, 255, 255, 0.86);
  margin-bottom: 28px;
  line-height: 1.55;
}
.hero-subtitle-soft {
  color: var(--cyan-300);
  font-weight: 500;
}

.hero-facts {
  margin: 0 0 28px;
  display: grid;
  gap: 12px;
}
.fact {
  background: rgba(255, 255, 255, 0.07);
  border: 1px solid rgba(255, 255, 255, 0.12);
  border-radius: var(--radius);
  padding: 14px 16px;
  backdrop-filter: blur(4px);
}
.fact dt {
  font-size: 11px;
  letter-spacing: 0.2em;
  text-transform: uppercase;
  color: var(--cyan-300);
  margin-bottom: 4px;
}
.fact dd { margin: 0; font-size: 15px; line-height: 1.5; }
.fact strong { font-size: 18px; font-weight: 700; }
.muted { color: rgba(255, 255, 255, 0.65); }

.hero-cta {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  margin-bottom: 24px;
}
.hero-tagline {
  margin-top: 6px;
  font-size: 14px;
  color: rgba(255, 255, 255, 0.75);
  letter-spacing: 0.02em;
}
.hero-tagline em {
  font-style: normal;
  color: var(--gold-400);
  font-weight: 600;
}

.hero-skyline-svg {
  position: absolute;
  inset: auto 0 0 0;
  width: 100%;
  height: 220px;
  display: block;
  pointer-events: none;
  z-index: 1;
  opacity: 0.95;
}

/* Buttons ------------------------------------------------------- */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  min-height: 48px;
  padding: 12px 22px;
  border-radius: 999px;
  font-size: 15px;
  font-weight: 600;
  border: 1px solid transparent;
  cursor: pointer;
  transition: transform 0.15s ease, box-shadow 0.15s ease, background 0.15s ease;
}
.btn-primary {
  background: var(--gold-400);
  color: var(--navy-900);
}
.btn-primary:hover, .btn-primary:focus {
  transform: translateY(-1px);
  box-shadow: 0 8px 22px rgba(243, 200, 117, 0.45);
}
.btn-ghost {
  background: rgba(255, 255, 255, 0.10);
  color: var(--white);
  border-color: rgba(255, 255, 255, 0.30);
}
.btn-ghost:hover, .btn-ghost:focus {
  background: rgba(255, 255, 255, 0.18);
}
.btn-block { width: 100%; }
.btn-icon { font-size: 18px; }

/* Section heads ------------------------------------------------- */
.section-head {
  text-align: center;
  margin-bottom: 32px;
}
.section-kicker {
  display: inline-block;
  font-size: 11px;
  letter-spacing: 0.3em;
  color: var(--blue-500);
  font-weight: 600;
  text-transform: uppercase;
  margin-bottom: 10px;
}
.section-head h2 {
  font-size: clamp(24px, 5vw, 32px);
  color: var(--navy-900);
}
.section-head.light .section-kicker { color: var(--cyan-300); }
.section-head.light h2 { color: var(--white); }
.section-head.light .contact-sub {
  margin-top: 10px;
  color: rgba(255, 255, 255, 0.78);
  font-size: 14px;
}

/* Agenda / Timeline -------------------------------------------- */
.agenda {
  background: var(--bg-soft);
  padding: 56px 18px 64px;
}
.timeline {
  max-width: 720px;
  margin: 0 auto;
  position: relative;
}
.timeline::before {
  content: "";
  position: absolute;
  top: 6px;
  bottom: 6px;
  left: 18px;
  width: 2px;
  background: linear-gradient(to bottom, var(--blue-400), var(--cyan-300) 45%, transparent);
  opacity: 0.45;
}
.slot {
  position: relative;
  padding: 0 0 18px 46px;
}
.slot::before {
  content: "";
  position: absolute;
  left: 11px;
  top: 8px;
  width: 16px;
  height: 16px;
  border-radius: 50%;
  background: var(--white);
  border: 3px solid var(--blue-500);
  box-shadow: var(--shadow-sm);
}
.slot.featured::before { border-color: var(--gold-400); background: var(--gold-400); }
.slot.panel::before { border-color: var(--blue-400); background: var(--blue-400); }
.slot.anchor::before { border-color: #34c759; background: #34c759; }
.slot.end::before { background: var(--ink-300); border-color: var(--ink-300); }

.slot-time {
  font-variant-numeric: tabular-nums;
  font-weight: 700;
  font-size: 13px;
  color: var(--blue-500);
  letter-spacing: 0.04em;
  margin-bottom: 4px;
}
.slot-body {
  background: var(--white);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 14px 16px;
  box-shadow: var(--shadow-sm);
}
.slot.featured .slot-body { border-color: var(--gold-400); }
.slot.panel .slot-body { border-color: rgba(58, 142, 239, 0.4); }
.slot-title {
  font-size: 16px;
  line-height: 1.45;
  color: var(--ink-900);
}
.slot-quote {
  margin-top: 6px;
  color: var(--ink-700);
  font-size: 14px;
  font-style: italic;
}
.slot-meta {
  margin-top: 6px;
  color: var(--ink-500);
  font-size: 13px;
  line-height: 1.55;
}
.slot-tag {
  display: inline-block;
  font-size: 11px;
  letter-spacing: 0.18em;
  text-transform: uppercase;
  color: var(--navy-800);
  background: var(--gold-400);
  padding: 2px 8px;
  border-radius: 999px;
  font-weight: 700;
  margin-bottom: 6px;
}
.panel-tag { background: var(--blue-400); color: var(--white); }

/* Featured speakers --------------------------------------------- */
.speakers {
  padding: 56px 18px 56px;
  max-width: var(--maxw);
  margin: 0 auto;
}
.speakers-grid {
  display: grid;
  gap: 18px;
}
.speaker-card {
  background: var(--white);
  border: 1px solid var(--line);
  border-radius: var(--radius-lg);
  padding: 22px 20px;
  text-align: center;
  box-shadow: var(--shadow-sm);
  transition: transform 0.18s ease, box-shadow 0.18s ease;
}
.speaker-card:hover {
  transform: translateY(-2px);
  box-shadow: var(--shadow-md);
}
.speaker-portrait {
  width: 132px;
  height: 132px;
  margin: 0 auto 14px;
  border-radius: 50%;
  overflow: hidden;
  background: var(--bg-soft);
  border: 3px solid var(--white);
  box-shadow: 0 6px 18px rgba(8, 22, 50, 0.18);
}
.speaker-portrait img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  display: block;
}
.speaker-name {
  font-size: 18px;
  color: var(--navy-900);
  margin-bottom: 4px;
  line-height: 1.35;
}
.speaker-name-en {
  display: block;
  font-size: 12px;
  letter-spacing: 0.06em;
  color: var(--blue-500);
  font-weight: 600;
  margin-top: 2px;
}
.speaker-bio {
  margin: 12px 0 0;
  padding: 0;
  list-style: none;
  text-align: left;
}
.speaker-bio li {
  position: relative;
  padding: 4px 0 4px 14px;
  font-size: 13.5px;
  color: var(--ink-700);
  line-height: 1.55;
  border-top: 1px dashed var(--line);
}
.speaker-bio li:first-child { border-top: none; }
.speaker-bio li::before {
  content: "";
  position: absolute;
  left: 0;
  top: 13px;
  width: 6px;
  height: 6px;
  border-radius: 50%;
  background: var(--gold-400);
}

/* Forums -------------------------------------------------------- */
.forums {
  padding: 56px 18px 64px;
  max-width: var(--maxw);
  margin: 0 auto;
}
.forum-card {
  background: var(--white);
  border: 1px solid var(--line);
  border-radius: var(--radius-lg);
  padding: 22px;
  box-shadow: var(--shadow-md);
  margin-bottom: 18px;
  position: relative;
  overflow: hidden;
}
.forum-card::after {
  content: "";
  position: absolute;
  top: 0;
  right: 0;
  width: 80px;
  height: 80px;
  background: radial-gradient(circle at top right, rgba(36, 112, 214, 0.10), transparent 70%);
  pointer-events: none;
}
.forum-num {
  display: inline-block;
  font-size: 11px;
  letter-spacing: 0.24em;
  text-transform: uppercase;
  color: var(--white);
  background: var(--blue-500);
  padding: 4px 10px;
  border-radius: 999px;
  font-weight: 700;
  margin-bottom: 10px;
}
.forum-card h3 {
  font-size: 19px;
  color: var(--navy-900);
  line-height: 1.4;
  margin-bottom: 14px;
}
.forum-people { display: grid; gap: 12px; margin: 0; }
.forum-people dt {
  font-size: 11px;
  letter-spacing: 0.2em;
  color: var(--blue-500);
  text-transform: uppercase;
  font-weight: 600;
  margin-bottom: 4px;
}
.forum-people dd {
  margin: 0;
  color: var(--ink-700);
  font-size: 14px;
  line-height: 1.65;
}

/* Highlights ---------------------------------------------------- */
.highlights {
  background: var(--bg-soft);
  padding: 56px 18px 64px;
}
.hl-grid {
  display: grid;
  gap: 12px;
  max-width: 720px;
  margin: 0 auto;
}
.hl-grid li {
  display: flex;
  align-items: flex-start;
  gap: 14px;
  background: var(--white);
  padding: 16px 18px;
  border-radius: var(--radius);
  border: 1px solid var(--line);
  box-shadow: var(--shadow-sm);
}
.hl-check {
  flex: 0 0 28px;
  width: 28px;
  height: 28px;
  border-radius: 50%;
  background: var(--blue-500);
  color: var(--white);
  display: inline-flex;
  align-items: center;
  justify-content: center;
  margin-top: 2px;
  box-shadow: 0 4px 10px rgba(36, 112, 214, 0.25);
}
.hl-check svg { width: 16px; height: 16px; display: block; }

.icon-arrow {
  display: inline-block;
  vertical-align: middle;
  margin: 0 2px;
  color: var(--gold-400);
}
.hl-tagline .icon-arrow { color: var(--blue-500); }
.hl-grid h3 {
  font-size: 15px;
  color: var(--navy-900);
  margin-bottom: 2px;
}
.hl-grid p {
  font-size: 14px;
  color: var(--ink-500);
}
.hl-tagline {
  text-align: center;
  margin-top: 28px;
  color: var(--ink-700);
  font-size: 15px;
}
.hl-tagline strong { color: var(--blue-500); }

/* Contact / QR --------------------------------------------------- */
.contact {
  background:
    radial-gradient(ellipse at top, rgba(58, 142, 239, 0.25), transparent 60%),
    linear-gradient(160deg, var(--navy-900), var(--navy-700));
  color: var(--white);
  padding: 56px 18px 72px;
}
.qr-grid {
  max-width: 720px;
  margin: 0 auto;
  display: grid;
  gap: 16px;
}
.qr-card {
  background: rgba(255, 255, 255, 0.06);
  border: 1px solid rgba(255, 255, 255, 0.14);
  border-radius: var(--radius-lg);
  padding: 20px;
  text-align: center;
  backdrop-filter: blur(6px);
}
.qr-frame {
  background: var(--white);
  border-radius: var(--radius);
  padding: 16px;
  display: inline-block;
  margin-bottom: 14px;
  box-shadow: var(--shadow-md);
}
.qr-frame img {
  width: 100%;
  max-width: 220px;
  aspect-ratio: 1 / 1;
  object-fit: contain;
}
.qr-card h3 {
  font-size: 17px;
  margin-bottom: 6px;
}
.qr-card p {
  color: rgba(255, 255, 255, 0.78);
  font-size: 14px;
  margin-bottom: 14px;
  line-height: 1.55;
}
.qr-card--button-only {
  display: flex;
  flex-direction: column;
  justify-content: center;
  align-items: center;
}
.qr-card--button-only p {
  font-size: 15px;
  max-width: 260px;
}
.qr-card--button-only .btn-block {
  max-width: 280px;
  width: 100%;
}

/* Footer -------------------------------------------------------- */
.site-footer {
  background: var(--navy-900);
  color: rgba(255, 255, 255, 0.72);
  padding: 36px 22px 32px;
}
.footer-inner {
  max-width: var(--maxw);
  margin: 0 auto;
  display: grid;
  gap: 22px;
}
.footer-block h4 {
  font-size: 11px;
  letter-spacing: 0.24em;
  text-transform: uppercase;
  color: var(--cyan-300);
  margin-bottom: 8px;
}
.footer-block p {
  font-size: 13px;
  line-height: 1.7;
  color: rgba(255, 255, 255, 0.78);
}
.copyright {
  font-size: 12px;
  color: rgba(255, 255, 255, 0.45);
  border-top: 1px solid rgba(255, 255, 255, 0.10);
  padding-top: 18px;
  text-align: center;
}

/* Reduce motion --------------------------------------------------*/
@media (prefers-reduced-motion: reduce) {
  * { transition: none !important; }
}

/* ============================================================== */
/* Tablet / desktop                                                */
/* ============================================================== */
@media (min-width: 720px) {
  .site-header { padding: 14px 28px; }
  .nav { gap: 22px; font-size: 15px; }

  .hero-inner { padding: 84px 32px 110px; }
  .hero-facts { grid-template-columns: 1fr 1fr; gap: 16px; }
  .hero-cta { gap: 14px; }

  .agenda, .speakers, .forums, .highlights, .contact { padding: 80px 28px; }
  .speakers-grid { grid-template-columns: 1fr 1fr; gap: 22px; }

  .timeline::before { left: 22px; }
  .slot { padding-left: 56px; padding-bottom: 22px; }
  .slot::before { left: 15px; width: 18px; height: 18px; }

  .hl-grid { grid-template-columns: 1fr 1fr; gap: 14px; }

  .qr-grid { grid-template-columns: 1fr 1fr; gap: 22px; }

  .footer-inner { grid-template-columns: 1fr 1fr; }
  .copyright { grid-column: 1 / -1; }
}

@media (min-width: 1024px) {
  .hero-title { font-size: 48px; }
  .hl-grid { grid-template-columns: repeat(4, 1fr); }
  .forum-card { padding: 30px; }
  .forum-card h3 { font-size: 22px; }
  .forum-people { grid-template-columns: 200px 1fr; align-items: start; gap: 24px; }
  .speakers-grid { grid-template-columns: repeat(4, 1fr); gap: 22px; }
  .speaker-card { padding: 26px 18px; }
}