:root{
  --bg:#0b1220;--bg2:#101a2e;--panel:#141f36;--line:#233150;--text:#e6edf8;--muted:#9fb0cc;
  --accent:#22d3ee;--accent-2:#0ea5e9;--good:#34d399;--bad:#f87171;--warn:#fbbf24;
  --radius:14px;--maxw:1120px;--font:ui-sans-serif,system-ui,-apple-system,"Segoe UI",Roboto,Inter,Helvetica,Arial,sans-serif;
}
*{box-sizing:border-box}
html,body{overflow-x:hidden}
html{scroll-behavior:smooth;-webkit-text-size-adjust:100%}
body{margin:0;font-family:var(--font);background:var(--bg);color:var(--text);line-height:1.6;font-size:17px}
a{color:var(--accent);text-decoration:none}
a:hover{text-decoration:underline}
img{max-width:100%;height:auto}
.wrap{max-width:var(--maxw);margin:0 auto;padding:0 20px}
.wrap.narrow{max-width:780px}
.center{text-align:center}
.muted{color:var(--muted)}
.small{font-size:.9rem}
.skip{position:absolute;left:-999px;top:0;background:var(--accent);color:#000;padding:8px}
.skip:focus{left:8px;z-index:100}
h1,h2,h3,h4{line-height:1.2;margin:0 0 .5em;font-weight:700;letter-spacing:-.01em}
h1{font-size:clamp(1.8rem,4vw,2.6rem)}
h2{font-size:clamp(1.35rem,2.6vw,1.75rem);margin-top:1.6em}
h3{font-size:1.15rem}
.lead{font-size:1.15rem;color:var(--muted)}
.kicker{color:var(--accent);font-weight:600;font-size:.85rem;text-transform:uppercase;letter-spacing:.08em;margin:0 0 .6em}

/* header */
.site-header{position:sticky;top:0;z-index:50;background:rgba(11,18,32,.88);backdrop-filter:blur(10px);border-bottom:1px solid var(--line)}
.header-row{display:flex;align-items:center;justify-content:space-between;gap:16px;height:64px}
.brand{display:flex;align-items:center;gap:10px;font-weight:800;font-size:1.15rem;color:var(--text)}
.brand:hover{text-decoration:none}
.nav{display:flex;align-items:center;gap:18px}
.nav>a:not(.btn){color:var(--text);font-weight:500}
.lang{position:relative}
.lang summary{cursor:pointer;list-style:none;color:var(--text)}
.lang summary::-webkit-details-marker{display:none}
.lang-menu{position:absolute;right:0;top:130%;background:var(--panel);border:1px solid var(--line);border-radius:10px;padding:8px;display:grid;min-width:160px;z-index:60}
.lang-menu a{padding:6px 10px;color:var(--text);border-radius:6px}
.lang-menu a[aria-current]{background:var(--bg2)}

/* buttons */
.btn{display:inline-flex;align-items:center;justify-content:center;gap:8px;padding:12px 20px;border-radius:10px;font-weight:700;border:1px solid transparent;cursor:pointer;font-size:1rem;transition:transform .08s,box-shadow .2s;white-space:nowrap}
.btn:hover{text-decoration:none;transform:translateY(-1px)}
.btn-primary{background:linear-gradient(135deg,var(--accent),var(--accent-2));color:#04121a;box-shadow:0 6px 24px rgba(34,211,238,.25)}
.btn-ghost{background:transparent;color:var(--text);border-color:var(--line)}
.btn-ghost:hover{border-color:var(--accent)}
.btn-sm{padding:8px 14px;font-size:.9rem}
.btn-lg{padding:15px 26px;font-size:1.05rem}
.btn-block{width:100%}

/* hero */
.hero{padding:56px 0 40px;background:radial-gradient(900px 400px at 15% -10%,rgba(34,211,238,.18),transparent 60%),radial-gradient(700px 400px at 90% 10%,rgba(14,165,233,.14),transparent 60%)}
.hero-grid{display:grid;grid-template-columns:1.3fr .9fr;gap:40px;align-items:start}
.checks{list-style:none;padding:0;margin:18px 0}
.checks li{padding:6px 0 6px 30px;position:relative}
.checks li::before{content:"✓";position:absolute;left:0;top:6px;color:var(--good);font-weight:800}
.hero-actions{display:flex;gap:12px;flex-wrap:wrap;margin:18px 0 12px}
.hero-card{background:var(--panel);border:1px solid var(--line);border-radius:var(--radius);padding:22px;box-shadow:0 20px 60px rgba(0,0,0,.35)}
.hero-card-top{color:var(--muted);font-size:.85rem;text-transform:uppercase;letter-spacing:.08em}
.hero-code{font-family:ui-monospace,SFMono-Regular,Menlo,monospace;font-size:1.9rem;font-weight:800;color:var(--accent);display:flex;align-items:center;gap:12px;margin:6px 0 14px;letter-spacing:.06em}
table.mini{width:100%;border-collapse:collapse;margin:0 0 16px;font-size:.95rem}
table.mini td{padding:8px 0;border-bottom:1px solid var(--line)}
table.mini td:last-child{text-align:right}

/* sections */
.section{padding:48px 0}
.section.alt{background:var(--bg2)}
.section.final{background:linear-gradient(180deg,var(--bg2),var(--bg));padding:64px 0}
.row-between{display:flex;justify-content:space-between;align-items:baseline;gap:16px;flex-wrap:wrap}
.cards{display:grid;grid-template-columns:repeat(3,1fr);gap:18px;margin-top:20px}
.cards-2{grid-template-columns:repeat(2,1fr)}
.card{display:block;background:var(--panel);border:1px solid var(--line);border-radius:var(--radius);padding:20px;color:var(--text);transition:border-color .2s,transform .1s}
.card:hover{text-decoration:none;border-color:var(--accent);transform:translateY(-2px)}
.card h3{margin:.3em 0 .4em}
.card p{margin:0 0 .6em;color:var(--muted);font-size:.97rem}
.card .link{color:var(--accent);font-weight:600}
.card-tool{border-left:4px solid var(--accent)}
.tag{display:inline-block;font-size:.72rem;text-transform:uppercase;letter-spacing:.08em;color:var(--accent);font-weight:700}
.chips{display:flex;gap:8px;flex-wrap:wrap;margin:16px 0}
.chip{padding:6px 14px;border:1px solid var(--line);border-radius:999px;color:var(--text);font-size:.9rem}
.chip.active,.chip:hover{border-color:var(--accent);color:var(--accent);text-decoration:none}

/* faq */
.faq details{border:1px solid var(--line);border-radius:10px;padding:0 18px;margin:10px 0;background:var(--panel)}
.faq summary{cursor:pointer;padding:14px 0;font-weight:600;list-style:none;position:relative;padding-right:28px}
.faq summary::-webkit-details-marker{display:none}
.faq summary::after{content:"+";position:absolute;right:0;top:12px;color:var(--accent);font-size:1.3rem}
.faq details[open] summary::after{content:"–"}
.faq p{margin:0 0 16px;color:var(--muted)}

/* code / cta */
.code-row{display:flex;align-items:center;gap:10px;flex-wrap:wrap;margin:8px 0 12px}
.code-row.center{justify-content:center}
.code-label{color:var(--muted);font-size:.9rem}
.code{font-family:ui-monospace,SFMono-Regular,Menlo,monospace;background:var(--bg);border:1px dashed var(--accent);color:var(--accent);padding:6px 12px;border-radius:8px;font-weight:800;letter-spacing:.06em;font-size:1.05rem}
.cta-box{display:grid;grid-template-columns:1.4fr 1fr;gap:20px;align-items:center;background:linear-gradient(135deg,rgba(34,211,238,.12),rgba(14,165,233,.06));border:1px solid rgba(34,211,238,.4);border-radius:var(--radius);padding:22px;margin:32px 0}
.cta-box strong{font-size:1.15rem}
.cta-box p{margin:.4em 0 0;color:var(--muted)}
.cta-actions{display:grid;gap:8px}

/* article */
.article{padding:32px 0 56px}
.article-grid{display:grid;grid-template-columns:minmax(0,1fr) 300px;gap:48px}
.tool-grid{display:grid;grid-template-columns:minmax(0,1fr) 300px;gap:48px}
.crumbs{font-size:.88rem;color:var(--muted);margin-bottom:12px}
.crumbs a{color:var(--muted)}
.byline{margin:-.2em 0 1em}
.disclosure{font-size:.85rem;color:var(--muted);background:var(--bg2);border-left:3px solid var(--warn);padding:10px 14px;border-radius:0 8px 8px 0;margin:0 0 24px}
.prose{font-size:1.05rem}
.prose h2{padding-top:.4em;scroll-margin-top:84px}
.prose h3{margin-top:1.4em;scroll-margin-top:84px}
.prose p{margin:0 0 1.1em}
.prose ul,.prose ol{padding-left:1.4em;margin:0 0 1.1em}
.prose li{margin:.3em 0}
.prose table{width:100%;border-collapse:collapse;margin:1.2em 0;font-size:.95rem;display:block;overflow-x:auto}
.prose th,.prose td{border:1px solid var(--line);padding:9px 12px;text-align:left;vertical-align:top}
.prose th{background:var(--bg2);white-space:nowrap}
.prose blockquote{border-left:3px solid var(--accent);margin:1.2em 0;padding:4px 18px;color:var(--muted)}
.prose code{background:var(--bg2);padding:2px 6px;border-radius:5px;font-size:.92em}
.prose pre{background:var(--bg2);padding:14px;border-radius:10px;overflow-x:auto}
.prose strong{color:#fff}
.prose hr{border:0;border-top:1px solid var(--line);margin:2em 0}
.article-side .sticky{position:sticky;top:84px;display:grid;gap:18px}
.side-cta{background:var(--panel);border:1px solid rgba(34,211,238,.4);border-radius:var(--radius);padding:18px}
.side-cta-title{font-weight:700;margin-bottom:6px}
.toc{background:var(--panel);border:1px solid var(--line);border-radius:var(--radius);padding:16px 18px;font-size:.92rem}
.toc-title{font-weight:700;margin-bottom:6px;text-transform:uppercase;font-size:.75rem;letter-spacing:.08em;color:var(--muted)}
.toc ol{margin:0;padding-left:1.2em}
.toc li{margin:.35em 0}
.toc a{color:var(--text)}
.toc-mobile{display:none;margin:0 0 20px}
.toc-mobile details{border:1px solid var(--line);border-radius:10px;padding:10px 16px;background:var(--panel)}
.toc-mobile summary{font-weight:700;cursor:pointer}
.faq-block{margin-top:40px}
.related{margin-top:40px}

/* tools */
.tool{background:var(--panel);border:1px solid var(--line);border-radius:var(--radius);padding:22px;margin:16px 0 28px;display:grid;gap:14px}
.tool label{display:grid;gap:6px;font-weight:600;font-size:.95rem}
.tool input[type=number],.tool select{width:100%;padding:12px 14px;border-radius:10px;border:1px solid var(--line);background:var(--bg);color:var(--text);font-size:1.05rem;font-family:inherit}
.tool input[type=range]{width:100%;accent-color:var(--accent)}
.results{display:grid;grid-template-columns:repeat(2,1fr);gap:12px;margin-top:6px}
.res{background:var(--bg);border:1px solid var(--line);border-radius:10px;padding:14px}
.res span{display:block;color:var(--muted);font-size:.85rem}
.res strong{font-size:1.35rem}
.res.good strong{color:var(--good)}
.res.bad strong{color:var(--bad)}

/* footer */
.site-footer{border-top:1px solid var(--line);padding:40px 0 28px;background:var(--bg2);font-size:.95rem}
.footer-grid{display:grid;grid-template-columns:1.5fr 1fr 1fr 1fr;gap:28px}
.footer-grid h4{margin:0 0 .6em;font-size:.85rem;text-transform:uppercase;letter-spacing:.08em;color:var(--muted)}
.footer-grid a{display:block;color:var(--text);padding:3px 0}
.brand-footer{font-weight:800;font-size:1.1rem;margin-bottom:6px}
.footer-note{color:var(--muted);font-size:.82rem;margin:22px 0 0;line-height:1.5}

@media (max-width:960px){
  .hero-grid,.article-grid,.tool-grid{grid-template-columns:minmax(0,1fr)}
  .article-main,.tool-grid>div{min-width:0}
  .article-side{display:none}
  .toc-mobile{display:block}
  .cards{grid-template-columns:repeat(2,1fr)}
  .footer-grid{grid-template-columns:1fr 1fr}
}
@media (max-width:640px){
  body{font-size:16px}
  .cards,.cards-2{grid-template-columns:1fr}
  .cta-box{grid-template-columns:1fr}
  .nav>a:not(.btn){display:none}
  .nav .btn-sm{padding:8px 10px;font-size:.8rem}
  .brand{font-size:1rem}
  .header-row{gap:8px}
  .results{grid-template-columns:1fr}
  .hero{padding:36px 0 28px}
  .footer-grid{grid-template-columns:1fr}
}

/* v2: example-style layout */
.hero-inner{max-width:860px}
.hero h1{font-size:clamp(2rem,5vw,3.4rem);margin:.4em 0 .4em}
.hero .accent{color:var(--accent)}
.pill{display:inline-block;border:1px solid var(--line);border-radius:999px;padding:6px 14px;background:rgba(20,31,54,.6);text-transform:none;letter-spacing:0;font-size:.85rem;color:var(--muted)}
.hero-actions.center{justify-content:center}
.stats{display:grid;grid-template-columns:repeat(4,1fr);gap:16px;margin-top:40px}
.stat{background:var(--panel);border:1px solid var(--line);border-radius:var(--radius);padding:20px}
.stat-n{font-size:2rem;font-weight:800;color:var(--accent)}
.stat-l{color:var(--muted);font-size:.9rem}
.card-meta{display:flex;justify-content:space-between;gap:10px;color:var(--muted);font-size:.85rem;margin-bottom:4px}
.article .toc{margin:18px 0 28px}
.article .lead{margin:.2em 0 .6em}
.checklist h3{margin:14px 0 4px}
.check{display:flex;gap:10px;align-items:flex-start;font-weight:400;padding:6px 0;border-bottom:1px solid var(--line)}
.check input{margin-top:5px;accent-color:var(--accent);width:18px;height:18px}
@media (max-width:640px){.stats{grid-template-columns:repeat(2,1fr)}.stat-n{font-size:1.5rem}}

/* welcome gift */
.section.gift{background:radial-gradient(700px 300px at 50% 0%,rgba(34,211,238,.12),transparent 70%),var(--bg)}
.gift-cards{display:grid;grid-template-columns:repeat(3,1fr);gap:20px;margin:28px auto 18px;max-width:900px}
.gift-card{background:var(--panel);border:1px solid var(--line);border-radius:18px;padding:28px 20px;text-align:center}
.gift-icon{display:flex;justify-content:center;margin-bottom:14px}
.gift-n{font-size:1.9rem;font-weight:800;letter-spacing:-.01em}
.gift-l{color:var(--muted);font-size:.95rem}
.lead.center{max-width:640px;margin-left:auto;margin-right:auto}
@media (max-width:640px){.gift-cards{grid-template-columns:1fr}}