:root{
    --bg:#0e1116; --panel:#161b22; --line:#232a35;
    --fg:#e8ecf3; --muted:#9aa5b5; --accent:#5b8dee; --accent-soft:#1d2942;
    --maxw:960px;
  }
  @media (prefers-color-scheme: light){
    :root{ --bg:#ffffff; --panel:#f6f8fb; --line:#e3e8ef;
           --fg:#12161c; --muted:#5b6676; --accent:#2563eb; --accent-soft:#e8effd; }
  }
  *{box-sizing:border-box}
  body{margin:0;background:var(--bg);color:var(--fg);
       font:16px/1.65 system-ui,-apple-system,"Segoe UI",Roboto,sans-serif;
       -webkit-font-smoothing:antialiased}
  .wrap{max-width:var(--maxw);margin:0 auto;padding:0 20px}
  a{color:var(--accent)}

  header{border-bottom:1px solid var(--line);position:sticky;top:0;
         background:var(--bg);background:color-mix(in srgb,var(--bg) 88%,transparent);
         backdrop-filter:blur(8px);z-index:10}
  .bar{display:flex;align-items:center;gap:16px;height:62px}
  .logo{font-weight:700;letter-spacing:-.02em;font-size:1.3rem;text-decoration:none;color:var(--fg)}
  .logo>span{color:var(--fg)}
  .logo>span>span{color:var(--accent)}
  nav{margin-left:auto;display:flex;gap:6px;align-items:center;flex-wrap:wrap}
  nav a{color:var(--muted);text-decoration:none;font-size:.92rem;padding:7px 11px;border-radius:7px}
  nav a:hover{color:var(--fg);background:var(--panel)}
  .lang{border:1px solid var(--line);background:transparent;color:var(--muted);
        font:inherit;font-size:.82rem;padding:5px 11px;border-radius:7px;cursor:pointer}
  .lang:hover{color:var(--fg);border-color:var(--accent)}

  .hero{padding:76px 0 60px;border-bottom:1px solid var(--line)}
  .hero h1{font-size:clamp(1.9rem,5vw,3.1rem);line-height:1.15;letter-spacing:-.025em;margin:0 0 18px}
  .hero p{font-size:clamp(1rem,2.2vw,1.18rem);color:var(--muted);max-width:60ch;margin:0 0 28px}
  .cta{display:inline-block;background:var(--accent);color:#fff;text-decoration:none;
       padding:11px 22px;border-radius:8px;font-weight:600;font-size:.95rem}
  .cta:hover{opacity:.9}
  .tag{display:inline-block;background:var(--accent-soft);color:var(--accent);
       font-size:.76rem;font-weight:600;letter-spacing:.06em;text-transform:uppercase;
       padding:5px 11px;border-radius:99px;margin-bottom:20px}

  section{padding:58px 0;border-bottom:1px solid var(--line)}
  h2{font-size:1.5rem;letter-spacing:-.02em;margin:0 0 10px}
  .sub{color:var(--muted);margin:0 0 30px;max-width:62ch}

  .grid{display:grid;gap:18px;grid-template-columns:repeat(auto-fit,minmax(240px,1fr))}
  .card{background:var(--panel);border:1px solid var(--line);border-radius:11px;padding:22px}
  .card h3{margin:0 0 8px;font-size:1.02rem}
  .card p{margin:0;color:var(--muted);font-size:.93rem}

  dl.facts{display:grid;grid-template-columns:minmax(150px,auto) 1fr;gap:1px;
           background:var(--line);border:1px solid var(--line);border-radius:11px;overflow:hidden;margin:0}
  dl.facts dt{background:var(--panel);padding:13px 16px;font-size:.88rem;color:var(--muted)}
  dl.facts dd{background:var(--bg);padding:13px 16px;margin:0;font-size:.93rem;word-break:break-word}
  @media (max-width:560px){
    dl.facts{grid-template-columns:1fr}
    dl.facts dt{padding-bottom:0;background:var(--bg)}
    dl.facts dd{padding-top:4px}
  }

  footer{padding:36px 0 48px;color:var(--muted);font-size:.85rem}
  footer p{margin:0 0 8px;max-width:75ch}
  .legal{font-size:.8rem;line-height:1.6}
  [hidden]{display:none!important}

  /* ---- QAM-4 constellation mark ---- */
  .logo{display:flex;align-items:center;gap:10px}
  .mark{flex:none}
  .mark .ax{stroke:currentColor;stroke-width:2;stroke-linecap:round;opacity:.42}
  .mark .ring{fill:none;stroke:currentColor;stroke-width:1.5;stroke-dasharray:3 4;opacity:.3}
  .mark .sym{fill:var(--accent)}

  .heroGrid{display:grid;grid-template-columns:1.25fr .75fr;gap:44px;align-items:center}
  @media (max-width:760px){ .heroGrid{grid-template-columns:1fr;gap:34px} }

  .constellation{width:100%;max-width:360px;margin-inline:auto;display:block;color:var(--muted)}
  .constellation .ax{stroke:currentColor;stroke-width:1.5;stroke-linecap:round;opacity:.5}
  .constellation .ring{fill:none;stroke:currentColor;stroke-width:1.2;stroke-dasharray:4 5;opacity:.35}
  .constellation .sym{fill:var(--accent)}
  .constellation .lbl{fill:currentColor;font:600 7px system-ui,sans-serif;opacity:.75}
  .constellation .bits{fill:var(--fg);font:600 6.5px ui-monospace,SFMono-Regular,Menlo,monospace;opacity:.9}
  /* symbols settle onto their decision points, like a receiver locking on */
  .constellation .sym circle{animation:lock .9s cubic-bezier(.34,1.3,.5,1) backwards}
  .constellation .sym circle:nth-child(1){animation-delay:.05s}
  .constellation .sym circle:nth-child(2){animation-delay:.17s}
  .constellation .sym circle:nth-child(3){animation-delay:.29s}
  .constellation .sym circle:nth-child(4){animation-delay:.41s}
  @keyframes lock{from{opacity:0;transform:scale(.3)}to{opacity:1;transform:scale(1)}}
  .constellation .sym circle{transform-box:fill-box;transform-origin:center}
  @media (prefers-reduced-motion:reduce){ .constellation .sym circle{animation:none} }

  /* ---- multi-page additions ---- */
  nav a[aria-current="page"]{color:var(--fg);background:var(--panel)}
  main.page{padding:52px 0 8px}
  main.page section{border-bottom:none;padding-top:0}
  .backlink{display:inline-block;margin-top:30px;color:var(--muted);text-decoration:none;font-size:.9rem}
  .backlink:hover{color:var(--accent)}
  main.page h1{font-size:1.5rem;letter-spacing:-.02em;margin:0 0 10px}