:root{
  --bg:#ffffff;
  --bg-alt:#f4f7fb;
  --surface:#ffffff;
  --surface-2:#eef2f8;
  --border:rgba(15,23,42,.12);
  --text:#0f1a30;
  --muted:#5a6685;
  --accent:#2563eb;
  --accent-2:#0891b2;
  --accent-grad:linear-gradient(120deg,#2563eb,#06b6d4);
  --radius:16px;
  --maxw:1120px;
}
*{box-sizing:border-box;margin:0;padding:0}
html{scroll-behavior:smooth}
body{
  font-family:'Inter',system-ui,-apple-system,sans-serif;
  background:var(--bg);
  color:var(--text);
  line-height:1.6;
  -webkit-font-smoothing:antialiased;
}
a{color:inherit;text-decoration:none}
.container{max-width:var(--maxw);margin:0 auto;padding:0 24px}

/* Buttons */
.btn{
  display:inline-flex;align-items:center;justify-content:center;
  font-weight:600;font-size:15px;
  padding:12px 22px;border-radius:999px;
  border:1px solid transparent;cursor:pointer;
  transition:transform .15s ease,box-shadow .2s ease,background .2s ease;
}
.btn:hover{transform:translateY(-2px)}
.btn-primary{background:var(--accent-grad);color:#fff;box-shadow:0 8px 22px rgba(37,99,235,.28)}
.btn-ghost{border-color:var(--border);color:var(--text);background:rgba(15,23,42,.02)}
.btn-ghost:hover{border-color:var(--accent-2)}
.btn-lg{padding:15px 30px;font-size:16px}
.btn-block{display:flex;width:100%}
.btn[aria-disabled="true"]{opacity:.75;cursor:default}
.btn[aria-disabled="true"]:hover{transform:none}

/* Header */
.site-header{
  position:sticky;top:0;z-index:50;
  background:rgba(255,255,255,.82);
  backdrop-filter:blur(14px);
  border-bottom:1px solid var(--border);
}
.header-inner{display:flex;align-items:center;justify-content:space-between;height:68px}
.brand{display:flex;align-items:baseline;gap:6px;font-family:'Space Grotesk',sans-serif}
.brand-mark{font-weight:700;font-size:22px;letter-spacing:.5px}
.brand-ver{font-weight:600;font-size:16px;color:var(--accent-2)}
.nav{display:flex;gap:28px}
.nav a{color:var(--muted);font-weight:500;font-size:15px;transition:color .2s}
.nav a:hover{color:var(--text)}
.nav-cta{display:inline-flex}
.nav-toggle{display:none;flex-direction:column;gap:5px;background:none;border:none;cursor:pointer;padding:6px}
.nav-toggle span{width:24px;height:2px;background:var(--text);border-radius:2px;transition:.3s}

/* Hero */
.hero{position:relative;overflow:hidden;padding:40px 0 56px;isolation:isolate}
.hero-bg{
  position:absolute;inset:0;z-index:-2;
  background:
    radial-gradient(1000px 600px at 70% -5%,rgba(37,99,235,.10),transparent 60%),
    linear-gradient(180deg,#f4f7fb,#ffffff);
}
.hero-inner{position:relative;width:100%;display:flex;flex-direction:column;align-items:center;text-align:center}
.hero-figure{
  width:100%;max-width:560px;
  border-radius:20px;overflow:hidden;
  border:1px solid var(--border);
  box-shadow:0 24px 60px rgba(15,23,42,.18);
}
.hero-figure img{display:block;width:100%;height:auto}
.hero-meta{display:flex;align-items:center;justify-content:center;gap:22px;margin:34px 0 28px;flex-wrap:wrap}
.hero-meta-item{display:flex;flex-direction:column;gap:3px}
.hm-label{font-size:12px;text-transform:uppercase;letter-spacing:1.5px;color:var(--accent-2)}
.hm-value{font-weight:600;font-size:16px}
.hero-meta-divider{width:1px;height:34px;background:var(--border)}
.hero-actions{display:flex;gap:14px;justify-content:center;flex-wrap:wrap}
/* Hero text (sponsors.html sub-page) */
.hero-eyebrow{color:var(--accent-2);font-weight:600;letter-spacing:2px;text-transform:uppercase;font-size:13px;margin-bottom:12px}
.hero-title{font-family:'Space Grotesk',sans-serif;font-weight:700;line-height:1;letter-spacing:-1px;color:var(--text)}
.hero-tagline{margin-top:14px;font-size:clamp(18px,2.5vw,24px);color:var(--muted);max-width:640px}

/* Top city banner */
.top-banner{position:relative;width:100%;overflow:hidden;line-height:0;border-bottom:3px solid #12233f}
.top-banner img{display:block;width:100%;height:300px;object-fit:cover;object-position:center 46%}
.banner-label{position:absolute;top:20px;left:30px;line-height:1.1;text-shadow:0 2px 12px rgba(0,0,0,.55)}
.bl-title{display:block;font-family:'Space Grotesk',sans-serif;font-size:30px;font-weight:700;color:#fff;letter-spacing:-.5px}
.bl-ver{color:#ff5a4d}
.bl-year{display:block;font-family:'Space Grotesk',sans-serif;font-size:18px;font-weight:600;color:#ffc23d;margin-top:2px}
.bl-date{display:block;font-family:'Inter',sans-serif;font-size:12px;font-weight:500;color:#fff;margin-top:6px;opacity:.95}

/* Brand logo (header + footer) */
.brand{display:flex;align-items:center}
.brand-logo{height:38px;width:auto;display:block}

/* Sponsors — Peering Asia style tier bands */
.section-head-center{margin-left:auto;margin-right:auto;text-align:center}
.sponsor-tiers{display:flex;flex-direction:column;gap:14px}
.tier-band{text-align:center;padding:26px 0;border-bottom:1px solid var(--border)}
.tier-band:last-child{border-bottom:none}
.tier-label{font-size:12px;font-weight:700;letter-spacing:2.5px;text-transform:uppercase;color:var(--muted);margin-bottom:20px}
.tier-logos{display:flex;flex-wrap:wrap;justify-content:center;align-items:center;gap:26px 56px}
.tier-logos img{width:auto;opacity:.9;transition:opacity .2s ease}
.tier-logos img:hover{opacity:1}
.tier-host .tier-logos img{height:52px}
.tier-diamond .tier-logos img{height:60px}
.tier-platinum .tier-logos img{height:50px}
.tier-gold .tier-logos img{height:42px}
.tier-silver .tier-logos img{height:34px}

/* Registration — free (button only) */
.register-free{
  max-width:600px;margin:0 auto;text-align:center;
  background:var(--surface);border:1px solid var(--border);border-radius:var(--radius);
  padding:44px 40px;position:relative;overflow:hidden;
}
.register-free::before{content:"";position:absolute;top:0;left:0;right:0;height:4px;background:var(--accent-grad)}
.register-free-badge{display:inline-block;font-size:12px;font-weight:700;letter-spacing:1.5px;text-transform:uppercase;color:#fff;background:var(--accent-grad);padding:6px 14px;border-radius:999px;margin-bottom:18px}
.register-free h3{font-family:'Space Grotesk',sans-serif;font-size:clamp(22px,3vw,28px);margin-bottom:12px;color:var(--text)}
.register-free-lead{color:var(--muted);font-size:16px;max-width:480px;margin:0 auto 26px}
.register-free .price-note{margin-top:14px}

/* Two-column content grid: main (left) + sponsor column (right) */
.content-grid{
  display:grid;
  grid-template-columns:minmax(0,1fr) 260px;
  gap:56px;
  align-items:stretch;
  padding-top:80px;padding-bottom:88px;
}
.content-main .block + .block{margin-top:72px}

/* Sponsor column — stays visible on the right the whole scroll (sticky) */
.sponsor-col{position:relative;height:100%}
.sponsor-panel{
  position:sticky;top:88px;
  display:flex;flex-direction:column;align-items:stretch;
  max-height:calc(100vh - 108px);overflow-y:auto;
  background:var(--surface);border:1px solid var(--border);border-radius:16px;
  padding:22px 20px;
  box-shadow:0 8px 28px rgba(15,23,42,.08);
}

@media(max-width:980px){
  .content-grid{grid-template-columns:1fr;gap:56px;padding-top:56px}
  .sponsor-panel{position:static}
}
.rail-title{text-align:center;font-size:12px;font-weight:700;letter-spacing:2px;text-transform:uppercase;color:var(--text);margin-bottom:6px}
.rail-tier{display:flex;flex-direction:column;align-items:center;gap:10px;padding:14px 0;border-top:1px solid var(--border)}
.rail-tier-label{font-size:10px;font-weight:700;letter-spacing:1.5px;text-transform:uppercase;color:var(--muted)}
.rail-logo{display:flex;align-items:center;justify-content:center;height:34px;width:100%;opacity:.85;transition:opacity .2s ease,transform .2s ease}
.rail-logo img{max-height:34px;max-width:130px;width:auto}
.rail-logo:hover{opacity:1;transform:scale(1.05)}
.tier-host .rail-logo img,.rail-tier:first-of-type .rail-logo img{max-height:30px}
.rail-cta{display:flex;align-items:center;justify-content:center;gap:5px;margin-top:14px;padding:9px 8px;border-radius:999px;border:1px dashed var(--border);color:var(--muted);font-size:11px;font-weight:600;line-height:1;white-space:nowrap;letter-spacing:.2px;transition:.2s}
.rail-cta:hover{border-color:var(--accent);color:var(--accent)}

/* Sections */
.section{padding:88px 0}
.section-alt{background:var(--bg-alt)}
.section-head{margin-bottom:44px;max-width:620px}
.section-tag{display:inline-block;color:var(--accent-2);font-weight:600;font-size:13px;letter-spacing:2px;text-transform:uppercase;margin-bottom:12px}
.section-head h2{font-family:'Space Grotesk',sans-serif;font-size:clamp(28px,4vw,40px);line-height:1.15;font-weight:700;letter-spacing:-.5px}

/* About */
.about-grid{display:grid;grid-template-columns:1fr 1fr;gap:48px;align-items:center}
.about-lead p{font-size:22px;font-weight:500;color:var(--text);line-height:1.4}
.about-body p{color:var(--muted);margin-bottom:16px}
.stats{display:grid;grid-template-columns:repeat(4,1fr);gap:20px;margin-top:56px}
.stat{background:var(--surface);border:1px solid var(--border);border-radius:var(--radius);padding:28px 20px;text-align:center}
.stat-num{display:block;font-family:'Space Grotesk',sans-serif;font-size:34px;font-weight:700;background:var(--accent-grad);-webkit-background-clip:text;background-clip:text;color:transparent}
.stat-label{display:block;margin-top:6px;color:var(--muted);font-size:14px}

/* Outline table */
.outline-table{border:1px solid var(--border);border-radius:var(--radius);overflow:hidden;background:var(--surface)}
.outline-row{display:grid;grid-template-columns:240px 1fr;border-bottom:1px solid var(--border)}
.outline-row:last-child{border-bottom:none}
.outline-key{padding:20px 24px;font-weight:600;background:var(--surface-2);color:var(--text)}
.outline-val{padding:20px 24px;color:var(--muted)}
.outline-val a{color:var(--accent-2);text-decoration:underline;text-underline-offset:3px}

/* Register */
.register-wrap{display:grid;grid-template-columns:400px 1fr;gap:40px;align-items:start}
.price-card{background:var(--surface);border:1px solid var(--border);border-radius:var(--radius);padding:34px;position:relative;overflow:hidden}
.price-card::before{content:"";position:absolute;top:0;left:0;right:0;height:4px;background:var(--accent-grad)}
.price-tier{color:var(--accent-2);font-weight:600;font-size:14px;letter-spacing:1px;text-transform:uppercase}
.price-amount{display:flex;align-items:baseline;gap:8px;margin:14px 0 22px}
.price-cur{font-size:20px;color:var(--muted);font-weight:600}
.price-num{font-family:'Space Grotesk',sans-serif;font-size:60px;font-weight:700;line-height:1}
.price-features{list-style:none;margin-bottom:26px}
.price-features li{padding:9px 0 9px 28px;position:relative;color:var(--muted);border-bottom:1px solid var(--border)}
.price-features li:last-child{border-bottom:none}
.price-features li::before{content:"✓";position:absolute;left:0;color:var(--accent-2);font-weight:700}
.price-note{margin-top:14px;text-align:center;font-size:13px;color:var(--muted)}
.register-side h3{font-family:'Space Grotesk',sans-serif;font-size:24px;margin-bottom:14px}
.register-side p{color:var(--muted);margin-bottom:16px}
.register-open strong{color:var(--accent-2)}

/* Venue */
.venue-grid{display:grid;grid-template-columns:1fr 1fr;gap:40px;align-items:stretch}
.venue-addr{font-size:18px;font-weight:600;color:var(--text);margin-bottom:16px}
.venue-info>p{color:var(--muted);margin-bottom:20px}
.venue-list{list-style:none;margin-bottom:24px}
.venue-list li{padding:10px 0;border-bottom:1px solid var(--border);color:var(--muted)}
.venue-list li strong{color:var(--text)}
.venue-map{border-radius:var(--radius);overflow:hidden;border:1px solid var(--border);min-height:340px}
.venue-map iframe{width:100%;height:100%;min-height:340px;border:0;filter:grayscale(.3) contrast(1.05)}

/* Hosts */
.hosts-wrap{display:flex;gap:24px;flex-wrap:wrap}
.host-card{display:flex;align-items:center;gap:24px;background:var(--surface);border:1px solid var(--border);border-radius:var(--radius);padding:28px 32px;flex:1;min-width:280px}
.host-logo{font-family:'Space Grotesk',sans-serif;font-weight:700;font-size:26px;padding:16px 22px;border:1px solid var(--border);border-radius:12px;background:var(--surface-2);color:var(--accent-2)}
.host-text h3{font-size:20px;margin-bottom:4px}
.host-text p{color:var(--muted);font-size:15px}
.sponsor-cta{display:flex;align-items:center;justify-content:space-between;gap:20px;flex-wrap:wrap;margin-top:40px;padding:28px 32px;border:1px dashed var(--border);border-radius:var(--radius)}
.sponsor-cta p{color:var(--muted)}

/* Footer */
.site-footer{background:var(--bg-alt);border-top:1px solid var(--border);padding:56px 0 24px}
.footer-inner{display:flex;justify-content:space-between;gap:40px;flex-wrap:wrap;margin-bottom:36px}
.footer-brand .brand-logo{height:34px;margin-bottom:10px}
.footer-brand .brand-mark{font-family:'Space Grotesk',sans-serif;font-size:24px}
.footer-brand .brand-ver{color:var(--accent-2)}
.footer-brand p{color:var(--muted);margin-top:8px;font-size:14px}
.footer-cols{display:flex;gap:64px}
.footer-col h4{font-size:14px;margin-bottom:14px;text-transform:uppercase;letter-spacing:1px;color:var(--muted)}
.footer-col a{display:block;color:var(--text);opacity:.8;padding:5px 0;font-size:15px;transition:opacity .2s}
.footer-col a:hover{opacity:1;color:var(--accent-2)}
.footer-bottom{display:flex;justify-content:space-between;gap:12px;flex-wrap:wrap;padding-top:24px;border-top:1px solid var(--border);color:var(--muted);font-size:14px}

/* Responsive */
@media(max-width:860px){
  .nav,.nav-cta{display:none}
  .nav-toggle{display:flex}
  .site-header.open .nav{
    display:flex;position:absolute;top:68px;left:0;right:0;flex-direction:column;gap:0;
    background:var(--bg-alt);border-bottom:1px solid var(--border);padding:8px 0;
  }
  .site-header.open .nav a{padding:14px 24px;border-bottom:1px solid var(--border)}
  .about-grid,.register-wrap,.venue-grid{grid-template-columns:1fr}
  .stats{grid-template-columns:repeat(2,1fr)}
  .sponsor-band-grid{grid-template-columns:repeat(3,1fr)}
  .outline-row{grid-template-columns:140px 1fr}
  .hero-meta-divider{display:none}
}
@media(max-width:480px){
  .stats{grid-template-columns:1fr}
  .sponsor-band-grid{grid-template-columns:repeat(2,1fr)}
  .outline-row{grid-template-columns:1fr}
  .outline-key{background:var(--surface-2)}
}