:root {
  --purple-900: #2a1a55;
  --purple-700: #4a2a8c;
  --purple-600: #5b34b0;
  --purple-500: #6e3ad6;
  --purple-400: #8a5cf0;
  --violet: #7c4dff;
  --ink: #161427;
  --muted: #6c6985;
  --line: #e7e3f4;
  --bg: #ffffff;
  --bg-soft: #f5f3fc;
  --radius: 16px;
}

* { box-sizing: border-box; margin: 0; padding: 0; }

html { scroll-behavior: smooth; }

body {
  font-family: "Sora", "Noto Sans SC", system-ui, -apple-system, Segoe UI, sans-serif;
  color: var(--ink);
  background: var(--bg);
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
}

html[lang="zh"] body {
  font-family: "Noto Sans SC", "Sora", system-ui, -apple-system, sans-serif;
}

img, svg { display: block; }
a { color: inherit; text-decoration: none; }

/* ---------- Buttons ---------- */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  font-weight: 700;
  font-size: 0.95rem;
  padding: 0.85rem 1.7rem;
  border-radius: 999px;
  border: 0;
  cursor: pointer;
  transition: transform 0.15s ease, box-shadow 0.15s ease, background 0.15s ease;
  white-space: nowrap;
}
.btn:hover { transform: translateY(-2px); }
.btn-primary {
  background: var(--purple-600);
  color: #fff;
  box-shadow: 0 10px 24px -10px rgba(91, 52, 176, 0.7);
}
.btn-primary:hover { background: var(--purple-500); }
.btn-light {
  background: #fff;
  color: var(--purple-700);
  box-shadow: 0 14px 30px -14px rgba(0, 0, 0, 0.5);
}
.btn-disabled {
  background: var(--line);
  color: var(--muted);
  cursor: not-allowed;
  font-family: inherit;
}
.btn-disabled:hover { transform: none; }
.btn-outline {
  background: transparent;
  color: var(--purple-700);
  box-shadow: inset 0 0 0 1.6px var(--purple-400);
}
.btn-outline:hover { background: var(--bg-soft); }

/* Disabled brochure CTA tooltip */
.brochure-cta { position: relative; display: inline-block; }
.brochure-cta::after {
  content: attr(data-tip-en);
  position: absolute;
  left: 50%;
  bottom: calc(100% + 10px);
  transform: translateX(-50%);
  background: var(--ink);
  color: #fff;
  font-size: 0.78rem;
  font-weight: 600;
  white-space: nowrap;
  padding: 0.4rem 0.7rem;
  border-radius: 8px;
  opacity: 0;
  pointer-events: none;
  transition: opacity 0.15s ease;
}
.brochure-cta::before {
  content: "";
  position: absolute;
  left: 50%;
  bottom: calc(100% + 4px);
  transform: translateX(-50%);
  border: 6px solid transparent;
  border-top-color: var(--ink);
  opacity: 0;
  pointer-events: none;
  transition: opacity 0.15s ease;
}
html[lang="zh"] .brochure-cta::after { content: attr(data-tip-zh); }
.brochure-cta:hover::after,
.brochure-cta:hover::before { opacity: 1; }

/* ---------- Header ---------- */
.site-header {
  position: sticky;
  top: 0;
  z-index: 50;
  display: flex;
  align-items: center;
  gap: 1.5rem;
  padding: 0.85rem clamp(1rem, 4vw, 3rem);
  background: rgba(255, 255, 255, 0.92);
  backdrop-filter: blur(10px);
  border-bottom: 1px solid var(--line);
}
.brand { display: flex; align-items: center; }
.brand-logo {
  height: 44px;
  width: 46px;
  object-fit: cover;
  object-position: left center;
  display: block;
}

.site-nav { display: flex; gap: 1.6rem; margin-left: auto; }
.site-nav a {
  font-size: 0.9rem;
  font-weight: 600;
  color: var(--ink);
  padding: 0.3rem 0;
  border-bottom: 2px solid transparent;
}
.site-nav a:hover { color: var(--purple-500); border-bottom-color: var(--purple-400); }

.header-actions { display: flex; align-items: center; gap: 0.9rem; }
.lang-toggle {
  display: flex;
  border: 1px solid var(--line);
  border-radius: 999px;
  overflow: hidden;
}
.lang-toggle button {
  border: 0;
  background: transparent;
  padding: 0.4rem 0.85rem;
  font-size: 0.82rem;
  font-weight: 700;
  cursor: pointer;
  color: var(--muted);
  font-family: inherit;
}
.lang-toggle button.active { background: var(--purple-600); color: #fff; }

/* ---------- Hero ---------- */
.hero {
  background: linear-gradient(180deg, #f1ecfb 0%, #ffffff 100%);
  padding: clamp(2.5rem, 6vw, 4.5rem) clamp(1.25rem, 6vw, 5rem) clamp(2.25rem, 5vw, 3.5rem);
  text-align: center;
}
.hero-text { max-width: 760px; margin: 0 auto; }
.hero-logo {
  height: clamp(60px, 11vw, 92px);
  width: auto;
  margin: 0 auto 1.5rem;
}
.hero-eyebrow {
  display: inline-block;
  font-size: 0.82rem;
  font-weight: 600;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  color: var(--purple-600);
  padding: 0.35rem 0.95rem;
  border: 1px solid var(--purple-400);
  border-radius: 999px;
  margin-bottom: 1.2rem;
}
.hero-title {
  font-size: clamp(2.8rem, 9vw, 5rem);
  font-weight: 800;
  line-height: 1.04;
  letter-spacing: -0.03em;
  color: var(--ink);
}
.hero-title span { color: var(--purple-500); }
html[lang="zh"] .hero-title { font-size: clamp(2.2rem, 7vw, 3.6rem); }
.hero-desc {
  font-size: 1.02rem;
  color: var(--muted);
  margin: 1.1rem auto 1.8rem;
  max-width: 580px;
}
.hero-banner {
  max-width: 1080px;
  margin: clamp(2rem, 5vw, 3rem) auto 0;
}
.hero-banner img {
  width: 100%;
  height: auto;
  border-radius: var(--radius);
  box-shadow: 0 24px 50px -28px rgba(91, 52, 176, 0.55);
}

/* ---------- Sections ---------- */
section { padding: clamp(3rem, 7vw, 5.5rem) clamp(1.25rem, 6vw, 5rem); }

.section-title {
  text-align: center;
  font-size: clamp(1.6rem, 4vw, 2.4rem);
  font-weight: 800;
  letter-spacing: -0.02em;
  margin-bottom: 2.6rem;
}
.section-title::after {
  content: "";
  display: block;
  width: 54px;
  height: 4px;
  border-radius: 2px;
  background: var(--purple-500);
  margin: 0.8rem auto 0;
}
.section-title--gap { margin-top: 3.5rem; }

/* ---------- About ---------- */
.about { background: var(--bg-soft); }
.about-grid {
  display: grid;
  grid-template-columns: minmax(0, 0.85fr) minmax(0, 1.15fr);
  gap: clamp(1.75rem, 5vw, 4rem);
  max-width: 1000px;
  margin: 0 auto;
  align-items: center;
}
.about-media img {
  width: 100%;
  height: auto;
  border-radius: var(--radius);
}
.about-accent {
  width: 68px;
  height: auto;
  border-radius: 8px;
  margin-bottom: 1.1rem;
}
.about-title {
  font-size: clamp(1.8rem, 5vw, 3rem);
  font-weight: 800;
  letter-spacing: -0.02em;
}
.about-title span { color: var(--purple-600); }
.about-title em { font-style: normal; color: var(--ink); font-weight: 600; }
.about-body {
  margin: 1.3rem 0 0;
  font-size: 1.08rem;
  color: var(--muted);
}
@media (max-width: 760px) {
  .about-grid { grid-template-columns: 1fr; }
}

/* ---------- Countdown ---------- */
.countdown { text-align: center; }
.countdown-stage { position: relative; margin-bottom: 2.5rem; }
.coming-soon {
  font-size: clamp(2.5rem, 11vw, 8rem);
  font-weight: 800;
  letter-spacing: -0.03em;
  color: var(--bg-soft);
  user-select: none;
  white-space: nowrap;
}
.timer {
  position: absolute;
  inset: 0;
  display: flex;
  align-items: center;
  justify-content: center;
  gap: clamp(0.6rem, 3vw, 2.2rem);
}
.cd-unit { display: flex; flex-direction: column; align-items: center; min-width: 64px; }
.cd-num {
  font-size: clamp(2.2rem, 7vw, 4.5rem);
  font-weight: 800;
  color: var(--purple-600);
  line-height: 1;
  font-variant-numeric: tabular-nums;
}
.cd-label {
  font-size: clamp(0.65rem, 1.6vw, 0.85rem);
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--muted);
  margin-top: 0.5rem;
}
.countdown-note { margin-top: 1rem; font-size: 0.9rem; color: var(--muted); }

/* ---------- Schedule ---------- */
.schedule { background: var(--bg-soft); }
.schedule-controls {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: 1rem 1.6rem;
  margin-bottom: 0.9rem;
}
.schedule-field {
  display: flex;
  flex-direction: column;
  gap: 0.4rem;
  font-size: 0.72rem;
  font-weight: 700;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--muted);
}
.schedule-field select {
  font-family: inherit;
  font-size: 0.95rem;
  font-weight: 600;
  letter-spacing: 0;
  text-transform: none;
  color: var(--ink);
  padding: 0.6rem 2.4rem 0.6rem 1rem;
  border: 1px solid var(--line);
  border-radius: 999px;
  background-color: #fff;
  background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='12' height='8' viewBox='0 0 12 8'%3E%3Cpath d='M1 1.5l5 5 5-5' fill='none' stroke='%236c6985' stroke-width='2' stroke-linecap='round' stroke-linejoin='round'/%3E%3C/svg%3E");
  background-repeat: no-repeat;
  background-position: right 1rem center;
  -webkit-appearance: none;
  -moz-appearance: none;
  appearance: none;
  cursor: pointer;
}
.schedule-field select:hover { border-color: var(--purple-400); }
.schedule-field select:focus-visible { outline: 2px solid var(--purple-400); outline-offset: 1px; }
.schedule-hint {
  text-align: center;
  font-size: 0.85rem;
  color: var(--muted);
  margin-bottom: 2.4rem;
}
.schedule-body { max-width: 860px; margin: 0 auto; }
.schedule-block + .schedule-block { margin-top: 2.2rem; }
.schedule-part {
  font-size: 1.15rem;
  font-weight: 800;
  color: var(--purple-700);
  margin-bottom: 1rem;
  padding-bottom: 0.45rem;
  border-bottom: 2px solid var(--line);
}
.session {
  display: flex;
  gap: 1.3rem;
  padding: 1.1rem 1.3rem;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: #fff;
}
.session + .session { margin-top: 0.8rem; }
.session-time {
  flex: none;
  width: 116px;
  display: flex;
  flex-direction: column;
  gap: 0.15rem;
}
.session-hours {
  font-size: 1.05rem;
  font-weight: 800;
  color: var(--purple-600);
  font-variant-numeric: tabular-nums;
  white-space: nowrap;
}
.session-date { font-size: 0.76rem; color: var(--muted); }
.session-info { flex: 1; min-width: 0; }
.session-tag {
  display: inline-block;
  font-size: 0.68rem;
  font-weight: 700;
  letter-spacing: 0.05em;
  text-transform: uppercase;
  padding: 0.22rem 0.65rem;
  border-radius: 999px;
  margin-bottom: 0.5rem;
}
.session-tag--keynote { background: var(--purple-600); color: #fff; }
.session-tag--us { background: #ece5fb; color: var(--purple-700); }
.session-tag--uk { background: #e3eefb; color: #285f9e; }
.session-tag--hk { background: #fbe3e6; color: #a02a3c; }
.session-tag--sg { background: #e0f2ed; color: #1f7a5c; }
.session-tag--sgus { background: #fdeedd; color: #a8651b; }
.session-title { font-weight: 700; font-size: 1rem; line-height: 1.4; }
.session-title--tba { font-weight: 600; font-style: italic; color: var(--muted); }
.session-speaker { font-size: 0.88rem; color: var(--muted); margin-top: 0.3rem; }

@media (max-width: 560px) {
  .session { flex-direction: column; gap: 0.55rem; }
  .session-time {
    width: auto;
    flex-direction: row;
    align-items: baseline;
    gap: 0.5rem;
  }
}

/* ---------- Highlights ---------- */
.highlights { background: var(--bg-soft); text-align: center; }
.stats {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 1.2rem;
  max-width: 980px;
  margin: 0 auto 2.6rem;
}
.stat {
  background: #fff;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 1.8rem 1rem;
}
.stat-num {
  display: block;
  font-size: clamp(2rem, 5vw, 3rem);
  font-weight: 800;
  color: var(--purple-600);
  letter-spacing: -0.02em;
}
.stat-label { display: block; font-size: 0.9rem; color: var(--muted); margin-top: 0.4rem; }

/* ---------- Institutions ---------- */
.logo-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(180px, 1fr));
  gap: 1rem;
  max-width: 1080px;
  margin: 0 auto;
}
.logo-card {
  display: flex;
  align-items: center;
  justify-content: center;
  text-align: center;
  min-height: 112px;
  padding: 1.2rem;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  font-weight: 700;
  font-size: 0.95rem;
  color: var(--purple-700);
  background: #fff;
  overflow: hidden;
  transition: transform 0.15s ease, box-shadow 0.15s ease;
}
.logo-card img {
  max-width: 100%;
  max-height: 66px;
  width: auto;
  height: auto;
  object-fit: contain;
}
.logo-card img.is-lg { transform: scale(2.2); }
.logo-card:hover {
  transform: translateY(-3px);
  box-shadow: 0 12px 26px -16px rgba(91, 52, 176, 0.6);
}

/* ---------- Speakers ---------- */
.speakers { background: var(--bg-soft); }
.speaker-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(200px, 1fr));
  gap: 1.8rem 1.4rem;
  max-width: 1160px;
  margin: 0 auto;
}
.speaker { text-align: center; }
.speaker-avatar {
  width: 116px;
  height: 116px;
  margin: 0 auto 0.85rem;
  border-radius: 50%;
  overflow: hidden;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 2rem;
  font-weight: 800;
  color: #fff;
  background: linear-gradient(150deg, hsl(var(--h), 62%, 58%), hsl(var(--h2), 64%, 42%));
  border: 3px solid #fff;
  box-shadow: 0 10px 22px -14px rgba(0, 0, 0, 0.6);
}
.speaker-avatar img {
  width: 100%;
  height: 100%;
  object-fit: cover;
}
.speaker-avatar--text { background: linear-gradient(150deg, hsl(var(--h), 62%, 58%), hsl(var(--h2), 64%, 42%)); }
.speaker-name {
  font-weight: 700;
  font-size: 1rem;
  color: var(--purple-700);
}
.speaker-role {
  font-size: 0.8rem;
  color: var(--muted);
  white-space: pre-line;
  line-height: 1.5;
  margin-top: 0.3rem;
}

/* ---------- Sponsor ---------- */
.sponsor { text-align: center; }
.sponsor-lead {
  max-width: 680px;
  margin: 0 auto;
  font-size: 1.08rem;
  color: var(--muted);
}
.sponsor-reach {
  list-style: none;
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: 1rem 2.6rem;
  margin: 2.2rem auto;
  max-width: 760px;
}
.sponsor-reach li {
  display: flex;
  flex-direction: column;
  gap: 0.2rem;
}
.sponsor-reach strong {
  font-size: clamp(1.8rem, 4vw, 2.4rem);
  font-weight: 800;
  color: var(--purple-600);
  letter-spacing: -0.02em;
}
.sponsor-reach span { font-size: 0.85rem; color: var(--muted); }
.sponsor-actions {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: 0.9rem;
}

/* ---------- Footer ---------- */
.site-footer { background: linear-gradient(135deg, #4a2a8c, #6e3ad6); color: #fff; }
.footer-cta {
  text-align: center;
  padding: clamp(3rem, 7vw, 5rem) 1.5rem;
}
.footer-cta h2 { font-size: clamp(1.6rem, 4vw, 2.4rem); font-weight: 800; }
.footer-cta p { color: rgba(255, 255, 255, 0.82); margin: 0.7rem 0 1.8rem; }
.footer-bottom {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 0.8rem 1.4rem;
  padding: 1.4rem clamp(1.25rem, 6vw, 5rem);
  border-top: 1px solid rgba(255, 255, 255, 0.18);
  font-size: 0.85rem;
}
.footer-email { font-weight: 600; }
.footer-email:hover { text-decoration: underline; }
.footer-copy { color: rgba(255, 255, 255, 0.7); }
.footer-social { display: flex; gap: 0.7rem; margin-left: auto; }
.footer-social a { display: flex; }
.footer-social img {
  width: 30px;
  height: 30px;
  display: block;
  opacity: 0.85;
  transition: opacity 0.15s ease, transform 0.15s ease;
}
.footer-social a:hover img { opacity: 1; transform: translateY(-2px); }

/* ---------- Responsive ---------- */
@media (max-width: 860px) {
  .site-nav { display: none; }
  .header-actions { margin-left: auto; }
  .stats { grid-template-columns: repeat(2, 1fr); }
}
@media (max-width: 560px) {
  .timer { position: static; margin-top: 1rem; }
  .coming-soon { display: none; }
  .countdown-stage { margin-bottom: 1.8rem; }
}