:root{
  --bg:#f3f6fa;--bg2:#e9eef5;--ink:#0f1722;--muted:#5a6678;--line:#d9e0ea;
  --card:rgba(255,255,255,.7);--accent:#0f766e;--accent2:#2563eb;--on-accent:#fff;
  --win:rgba(255,255,255,.72);--winline:rgba(15,23,34,.1);--sel:rgba(37,99,235,.14);
  --shadow:0 30px 70px -25px rgba(15,23,34,.35),0 2px 6px rgba(15,23,34,.08);
  --font:-apple-system,BlinkMacSystemFont,"SF Pro Text","Segoe UI",Roboto,"Helvetica Neue",Arial,sans-serif;
}
@media (prefers-color-scheme:dark){:root:not([data-theme=light]){
  --bg:#0b1118;--bg2:#111a24;--ink:#eaf0f7;--muted:#98a5b6;--line:#223041;
  --card:rgba(255,255,255,.05);--accent:#2dd4bf;--accent2:#60a5fa;--on-accent:#04201c;
  --win:rgba(22,32,44,.72);--winline:rgba(255,255,255,.1);--sel:rgba(96,165,250,.2);
  --shadow:0 30px 70px -25px #000,0 2px 6px rgba(0,0,0,.4)}}
:root[data-theme=dark]{
  --bg:#0b1118;--bg2:#111a24;--ink:#eaf0f7;--muted:#98a5b6;--line:#223041;
  --card:rgba(255,255,255,.05);--accent:#2dd4bf;--accent2:#60a5fa;--on-accent:#04201c;
  --win:rgba(22,32,44,.72);--winline:rgba(255,255,255,.1);--sel:rgba(96,165,250,.2);
  --shadow:0 30px 70px -25px #000,0 2px 6px rgba(0,0,0,.4)}
*{box-sizing:border-box}
html{-webkit-text-size-adjust:100%;scroll-behavior:smooth}
html[lang=vi] .en,html:not([lang=vi]) .vi{display:none!important}
body{margin:0;background:var(--bg);color:var(--ink);font:16px/1.6 var(--font);-webkit-font-smoothing:antialiased}
a{color:var(--accent2)}
.wrap{max-width:1080px;margin:0 auto;padding:0 20px}
.skip{position:absolute;left:-999px}.skip:focus{left:12px;top:8px;background:var(--ink);color:var(--bg);padding:8px 12px;border-radius:8px;z-index:9}
:focus-visible{outline:3px solid var(--accent2);outline-offset:2px;border-radius:6px}
.muted{color:var(--muted)}.small{font-size:.875rem}.center{text-align:center}
.top{position:sticky;top:0;z-index:5;background:color-mix(in srgb,var(--bg) 78%,transparent);backdrop-filter:saturate(1.6) blur(16px);-webkit-backdrop-filter:saturate(1.6) blur(16px);border-bottom:1px solid var(--line)}
.bar{display:flex;align-items:center;gap:16px;height:60px}
.brand{display:flex;align-items:center;gap:10px;font-weight:700;color:var(--ink);text-decoration:none;letter-spacing:-.01em}
.nav{display:flex;gap:20px;margin-left:auto}
.nav a{color:var(--muted);text-decoration:none;font-size:.95rem}.nav a:hover{color:var(--ink)}
.tools{display:flex;gap:8px}
.chip{font:600 .8rem var(--font);min-width:38px;height:34px;padding:0 10px;border-radius:999px;border:1px solid var(--line);background:var(--card);color:var(--ink);cursor:pointer;display:inline-flex;align-items:center;justify-content:center}
.chip:hover{border-color:var(--accent)}
.hero{padding:64px 0 48px;background:radial-gradient(900px 420px at 80% -10%,color-mix(in srgb,var(--accent2) 22%,transparent),transparent),radial-gradient(700px 380px at 0% 0%,color-mix(in srgb,var(--accent) 18%,transparent),transparent)}
.hero .wrap{display:grid;gap:44px;grid-template-columns:minmax(0,5fr) minmax(0,6fr);align-items:center}
.hero.center-only .wrap,.hero .wrap.center{display:block}
h1{font-size:clamp(2.1rem,5vw,3.5rem);line-height:1.08;letter-spacing:-.035em;margin:0 0 18px;font-weight:750}
h2{font-size:clamp(1.5rem,3vw,2rem);letter-spacing:-.02em;margin:0 0 20px;line-height:1.2}
h3{margin:0 0 6px;font-size:1.05rem}
.lead{font-size:1.15rem;color:var(--muted);max-width:34em;margin:0 0 26px}
.dl{display:flex;flex-wrap:wrap;gap:12px;margin:0 0 18px}.center .dl{justify-content:center}
.btn{display:inline-flex;flex-direction:column;justify-content:center;min-width:200px;padding:11px 22px;border-radius:14px;text-decoration:none;line-height:1.25;border:1px solid transparent}
.btn strong{font-size:1.05rem}.btn small{font-size:.74rem;opacity:.85}
.btn.primary{background:var(--ink);color:var(--bg)}
.btn.ghost{background:var(--card);color:var(--ink);border-color:var(--line)}
.btn.primary:hover{opacity:.88}.btn.ghost:hover{border-color:var(--accent)}
.btn.off{opacity:.55;cursor:default}
.sec{padding:64px 0}.alt{background:var(--bg2)}
.narrow{max-width:760px}
.two{display:grid;gap:40px;grid-template-columns:1fr 1fr}
.grid{list-style:none;margin:0;padding:0;display:grid;gap:14px;grid-template-columns:repeat(3,minmax(0,1fr))}
.grid li{padding:20px;border:1px solid var(--line);border-radius:18px;background:var(--card)}
.grid p{margin:0;color:var(--muted);font-size:.95rem}
.plain{padding-left:1.1em;margin:0}.plain li{margin:0 0 8px}
details{border-bottom:1px solid var(--line);padding:14px 0}
summary{cursor:pointer;font-weight:600}summary::marker{color:var(--accent)}
details p{margin:10px 0 0;color:var(--muted)}
.doc{max-width:760px;padding-top:52px;padding-bottom:72px}
.doc h1{font-size:clamp(1.9rem,4vw,2.6rem)}.doc h2{margin-top:2em;font-size:1.3rem}.doc h3{margin-top:1.4em}
.doc li{margin:0 0 .5em}
.foot{border-top:1px solid var(--line);padding:36px 0 44px;background:var(--bg2)}
.foot .cols{display:flex;flex-wrap:wrap;gap:24px;justify-content:space-between}
.foot nav{display:flex;flex-wrap:wrap;gap:18px;align-items:flex-start}.foot nav a{color:var(--muted);text-decoration:none}.foot nav a:hover{color:var(--ink)}
.foot p{margin:4px 0}.fine{font-size:.8rem;color:var(--muted);margin-top:24px!important;max-width:60em}

/* Cửa sổ minh hoạ */
.hero-shot{min-width:0}.cap{text-align:center;margin:12px 0 0}
.win{position:relative;display:grid;grid-template-columns:128px minmax(0,1fr) 92px;gap:0;border-radius:18px;background:var(--win);backdrop-filter:blur(20px);border:1px solid var(--winline);box-shadow:var(--shadow);overflow:hidden;font-size:11.5px;line-height:1.4;aspect-ratio:16/10.5}
.win p{margin:0}
.win-side{padding:12px 10px;border-right:1px solid var(--winline);background:color-mix(in srgb,var(--ink) 3%,transparent)}
.dots{display:flex;gap:6px;margin-bottom:14px}.dots s{width:10px;height:10px;border-radius:50%;background:#ff5f57}.dots s:nth-child(2){background:#febc2e}.dots s:nth-child(3){background:#28c840}
.win .h{color:var(--muted);font-weight:600;margin:12px 4px 4px;font-size:10.5px}
.win .it{display:flex;align-items:center;gap:6px;padding:4px 6px;border-radius:7px}.win .it.on{background:var(--sel)}
.win .it small{margin-left:auto;color:var(--muted)}
.dot{width:6px;height:6px;border-radius:50%;background:var(--muted)}.dot.ok{background:#22c55e}
.win-main{padding:12px 12px 10px;display:flex;flex-direction:column;gap:2px;min-width:0}
.crumb{font-weight:700;margin-bottom:8px}.crumb em{font-weight:400;color:var(--muted);font-style:normal;margin-left:6px}
.row{display:grid;grid-template-columns:18px minmax(0,1fr) 58px;gap:6px;align-items:center;padding:4px 6px;border-radius:7px;white-space:nowrap}
.row>span:nth-child(2){overflow:hidden;text-overflow:ellipsis}.row>span:last-child{color:var(--muted);text-align:right}
.row.hd{grid-template-columns:minmax(0,1fr) 58px;color:var(--muted);font-size:10.5px}.row.hd span:last-child{text-align:right}
.row.sel{background:var(--sel)}
.f{width:14px;height:11px;border-radius:3px;background:var(--accent2)}.f.dir{background:#f59e0b}.f.vid{background:#a855f7}.f.pdf{background:#ef4444}
.prog{margin-top:auto;padding:8px 10px;border-radius:10px;background:color-mix(in srgb,var(--ink) 6%,transparent)}
.prog div{display:flex;justify-content:space-between;margin-bottom:5px}
.prog i{display:block;height:5px;border-radius:9px;background:var(--winline);overflow:hidden}
.prog u{display:block;height:100%;width:64%;background:linear-gradient(90deg,var(--accent),var(--accent2))}
.win-phone{padding:12px 12px 12px 0;display:flex}
.scr{flex:1;border-radius:14px;background:linear-gradient(160deg,#1e293b,#020617);color:#fff;padding:12px 8px;display:flex;flex-direction:column;border:3px solid #0a0f18}
.clock{font-size:22px;font-weight:300;margin-top:6px}.date{font-size:9px;opacity:.7}
.bar2{margin:auto auto 2px;width:36px;height:3px;border-radius:3px;background:#ffffff80}

@media (max-width:860px){
  .hero .wrap{grid-template-columns:1fr}.hero{padding-top:40px}
  .grid{grid-template-columns:repeat(2,minmax(0,1fr))}.two{grid-template-columns:1fr}
}
@media (max-width:560px){
  .nav{display:none}.tools{margin-left:auto}
  .grid{grid-template-columns:1fr}.btn{width:100%}
  .win{grid-template-columns:96px minmax(0,1fr);aspect-ratio:auto;min-height:280px}.win-phone{display:none}
  .row{grid-template-columns:16px minmax(0,1fr) 50px}.sec{padding:44px 0}
}
@media (prefers-reduced-motion:reduce){html{scroll-behavior:auto}}