/* ============================================================
   ZENSYN GLOBAL — Design tokens
   Display: Space Grotesk / Body: Inter / Data: IBM Plex Mono
   Ink #14181F · Brand #1D2A52 · Amber #C9972E · Teal #14806B
   Surface #F6F5F1 · Surface-2 #EDEBE4 · Line #DAD6CC
   ============================================================ */

@import url('https://fonts.googleapis.com/css2?family=Space+Grotesk:wght@500;600;700&family=Inter:wght@400;500;600&family=IBM+Plex+Mono:wght@500&display=swap');

:root{
  --ink:#14181F;
  --ink-soft:#4B5160;
  --brand:#1D2A52;
  --brand-2:#293A6B;
  --amber:#C9972E;
  --amber-deep:#A87A1E;
  --teal:#14806B;
  --surface:#F6F5F1;
  --surface-2:#EDEBE4;
  --surface-3:#FFFFFF;
  --line:#DAD6CC;
  --line-strong:#C3BEB0;
  --radius:2px;
  --max:1120px;
}

*{box-sizing:border-box;}
html{scroll-behavior:smooth;}
body{
  margin:0;
  background:var(--surface);
  color:var(--ink);
  font-family:'Inter',system-ui,-apple-system,sans-serif;
  font-size:16px;
  line-height:1.6;
  -webkit-font-smoothing:antialiased;
}
h1,h2,h3,.display{
  font-family:'Space Grotesk',sans-serif;
  color:var(--brand);
  line-height:1.12;
  letter-spacing:-0.01em;
  margin:0 0 .5em;
}
h1{font-size:clamp(2.1rem,4.4vw,3.4rem); font-weight:700;}
h2{font-size:clamp(1.5rem,2.6vw,2rem); font-weight:600;}
h3{font-size:1.15rem; font-weight:600;}
p{margin:0 0 1em; color:var(--ink-soft);}
a{color:var(--brand-2);}
a.plain{color:inherit; text-decoration:none;}
strong{color:var(--ink);}
.mono{font-family:'IBM Plex Mono',monospace; letter-spacing:-0.01em;}
img,svg{max-width:100%; display:block;}

.wrap{max-width:var(--max); margin:0 auto; padding:0 28px;}
.hidden{display:none !important;}

/* ---------- Nav ---------- */
.nav{
  position:sticky; top:0; z-index:40;
  background:rgba(246,245,241,.92);
  backdrop-filter:saturate(140%) blur(6px);
  border-bottom:1px solid var(--line);
}
.nav .wrap{display:flex; align-items:center; justify-content:space-between; height:72px;}
.brand{display:flex; align-items:center; gap:10px; text-decoration:none;}
.brand-mark{width:26px; height:26px;}
.brand-word{font-family:'Space Grotesk',sans-serif; font-weight:700; font-size:1.15rem; color:var(--brand); letter-spacing:-0.01em;}
.nav-links{display:flex; align-items:center; gap:28px; font-size:.94rem; font-weight:500;}
.nav-links a{color:var(--ink-soft); text-decoration:none;}
.nav-links a:hover{color:var(--brand);}
.btn{
  display:inline-flex; align-items:center; gap:8px;
  padding:10px 20px; border-radius:var(--radius);
  font-weight:600; font-size:.92rem; text-decoration:none;
  border:1px solid transparent; cursor:pointer;
}
.btn-primary{background:var(--brand); color:#fff;}
.btn-primary:hover{background:var(--brand-2);}
.btn-ghost{border-color:var(--line-strong); color:var(--ink);}
.btn-ghost:hover{border-color:var(--brand);}
.lang-toggle{
  display:flex; border:1px solid var(--line-strong); border-radius:var(--radius);
  overflow:hidden; font-family:'IBM Plex Mono',monospace; font-size:.78rem; font-weight:500;
}
.lang-toggle button{
  border:0; background:transparent; padding:7px 11px; cursor:pointer; color:var(--ink-soft);
}
.lang-toggle button.active{background:var(--brand); color:#fff;}

/* ---------- Hero ---------- */
.hero{padding:88px 0 64px; border-bottom:1px solid var(--line);}
.eyebrow{
  display:inline-flex; align-items:center; gap:8px;
  font-family:'IBM Plex Mono',monospace; font-size:.76rem; font-weight:500;
  letter-spacing:.06em; text-transform:uppercase; color:var(--teal);
  margin-bottom:18px;
}
.eyebrow::before{content:''; width:7px; height:7px; background:var(--teal); border-radius:50%; display:inline-block;}
.hero-grid{display:grid; grid-template-columns:1.1fr .9fr; gap:56px; align-items:center;}
.hero p.lead{font-size:1.12rem; max-width:46ch;}
.hero-cta{display:flex; gap:14px; margin-top:28px; flex-wrap:wrap;}

/* channel rail — signature element */
.rail{position:relative; padding:20px 0;}
.rail-line{stroke:var(--line-strong); stroke-width:1.5;}
.rail-node text{font-family:'IBM Plex Mono',monospace; font-size:10px; fill:var(--ink-soft);}
.rail-hub{fill:var(--brand);}
.rail-dot{fill:var(--surface-3); stroke:var(--brand-2); stroke-width:1.6;}
.rail-dot.on{fill:var(--teal); stroke:var(--teal);}

/* ---------- Sections ---------- */
section{padding:64px 0;}
.section-tight{padding:48px 0;}
.section-head{max-width:56ch; margin-bottom:40px;}
.grid-3{display:grid; grid-template-columns:repeat(3,1fr); gap:28px;}
.grid-2{display:grid; grid-template-columns:1fr 1fr; gap:40px; align-items:center;}
.card{
  background:var(--surface-3); border:1px solid var(--line);
  border-radius:var(--radius); padding:26px 24px;
}
.card .idx{
  font-family:'IBM Plex Mono',monospace; font-size:.76rem; color:var(--amber-deep);
  font-weight:500; margin-bottom:12px; display:block;
}
.divider{border:0; border-top:1px solid var(--line); margin:0;}

.band{background:var(--brand); color:#fff;}
.band h2, .band h3{color:#fff;}
.band p{color:#C7CEE0;}
.band .card{background:rgba(255,255,255,.06); border-color:rgba(255,255,255,.16);}
.band .card p{color:#C7CEE0;}
.band .idx{color:var(--amber);}

.metric-row{display:flex; gap:36px; flex-wrap:wrap; margin-top:24px;}
.metric{border-left:2px solid var(--amber); padding-left:14px;}
.metric .num{font-family:'IBM Plex Mono',monospace; font-size:1.7rem; color:var(--brand); font-weight:500;}
.band .metric .num{color:#fff;}
.metric .lbl{font-size:.82rem; color:var(--ink-soft);}
.band .metric .lbl{color:#A9B3CC;}

.channels{display:flex; gap:12px; flex-wrap:wrap; margin-top:18px;}
.chip{
  font-family:'IBM Plex Mono',monospace; font-size:.78rem;
  border:1px solid var(--line-strong); padding:6px 12px; border-radius:20px;
  color:var(--ink-soft);
}
.chip.yt{border-color:var(--teal); color:var(--teal); font-weight:500;}

/* ---------- Footer ---------- */
footer{border-top:1px solid var(--line); padding:44px 0 36px;}
.foot-grid{display:flex; justify-content:space-between; flex-wrap:wrap; gap:24px; align-items:flex-start;}
.foot-links{display:flex; gap:24px; font-size:.9rem;}
.foot-links a{color:var(--ink-soft); text-decoration:none;}
.foot-links a:hover{color:var(--brand);}
.foot-note{font-size:.82rem; color:#8B8F99; margin-top:18px;}

/* ---------- Legal pages ---------- */
.legal-hero{padding:56px 0 32px; border-bottom:1px solid var(--line);}
.legal-updated{font-family:'IBM Plex Mono',monospace; font-size:.82rem; color:var(--ink-soft);}
.legal-body{max-width:74ch; padding:44px 0 80px;}
.legal-body h2{margin-top:2.2em; font-size:1.3rem;}
.legal-body h3{margin-top:1.6em; color:var(--ink); font-size:1.02rem;}
.legal-body ul{padding-left:1.2em;}
.legal-body li{color:var(--ink-soft); margin-bottom:.5em;}
.legal-note{
  background:var(--surface-2); border-left:3px solid var(--amber);
  padding:16px 18px; margin:1.6em 0; font-size:.94rem;
}
.legal-note strong{color:var(--brand);}
.toc{
  background:var(--surface-3); border:1px solid var(--line); border-radius:var(--radius);
  padding:20px 22px; margin-bottom:2em; font-size:.92rem;
}
.toc-title{font-family:'IBM Plex Mono',monospace; font-size:.76rem; text-transform:uppercase; letter-spacing:.06em; color:var(--ink-soft); margin-bottom:10px;}
.toc ol{margin:0; padding-left:1.2em;}
.toc a{color:var(--brand-2); text-decoration:none;}
.lang-block[data-lang="vi"]{border-top:1px dashed var(--line-strong); margin-top:2.2em; padding-top:1.8em;}

@media (max-width:860px){
  .hero-grid, .grid-2{grid-template-columns:1fr; gap:36px;}
  .grid-3{grid-template-columns:1fr;}
  .nav-links{display:none;}
  .foot-grid{flex-direction:column;}
}