:root{
  --ink:#0f1f33;--ink-2:#334155;--muted:#5b6b80;--line:#e2e8f0;--bg:#f7f9fc;--card:#fff;
  --brand:#0e7c66;--brand-2:#0a5f4e;--brand-soft:#e6f4f0;--accent:#f59e0b;--accent-soft:#fff7e6;
  --navy:#0f2a47;--danger:#b42318;--danger-soft:#fef3f2;--ok:#067647;--ok-soft:#ecfdf3;
  --radius:16px;--shadow:0 1px 2px rgba(15,31,51,.06),0 8px 24px rgba(15,31,51,.06);
}
*{box-sizing:border-box}
html{scroll-behavior:smooth}
body{margin:0;background:var(--bg);color:var(--ink);font:16px/1.6 Inter,ui-sans-serif,system-ui,-apple-system,"Segoe UI",Roboto,Arial,sans-serif;-webkit-font-smoothing:antialiased}
img{max-width:100%;height:auto}
a{color:var(--brand-2)}
a:hover{color:var(--brand)}
.wrap{max-width:1120px;margin:0 auto;padding:0 20px}
.narrow{max-width:780px}
.skip{position:absolute;left:-999px}.skip:focus{left:12px;top:12px;background:#fff;padding:8px 12px;z-index:99}

/* header */
.site-header{background:#fff;border-bottom:1px solid var(--line);position:sticky;top:0;z-index:20}
.nav{display:flex;align-items:center;justify-content:space-between;min-height:64px;gap:16px}
.logo{display:flex;align-items:center;gap:10px;font-weight:800;font-size:19px;letter-spacing:-.4px;color:var(--ink);text-decoration:none}
.logo svg{flex:none}
.logo b{color:var(--brand)}
.nav-links{display:flex;gap:22px;align-items:center}
.nav-links a{color:var(--ink-2);text-decoration:none;font-size:14.5px;font-weight:550}
.nav-links a:hover,.nav-links a[aria-current=page]{color:var(--brand)}
.nav-cta{background:var(--brand);color:#fff!important;padding:9px 14px;border-radius:10px}
.nav-cta:hover{background:var(--brand-2)}
.menu-btn{display:none;background:none;border:1px solid var(--line);border-radius:8px;padding:7px 10px;font:inherit;font-size:14px;cursor:pointer}

/* hero */
.hero{background:radial-gradient(1200px 400px at 85% -10%,#d6efe8 0,transparent 60%),linear-gradient(180deg,#fff, var(--bg));padding:56px 0 36px;border-bottom:1px solid var(--line)}
.eyebrow{display:inline-flex;gap:8px;align-items:center;font-size:12.5px;font-weight:700;letter-spacing:.06em;text-transform:uppercase;color:var(--brand-2);background:var(--brand-soft);padding:5px 10px;border-radius:999px}
h1{font-size:clamp(32px,4.6vw,52px);line-height:1.08;letter-spacing:-1.4px;margin:16px 0 14px;max-width:820px}
h2{font-size:clamp(24px,3vw,32px);line-height:1.2;letter-spacing:-.6px;margin:0 0 12px}
h3{font-size:19px;line-height:1.3;margin:0 0 8px;letter-spacing:-.2px}
.lead{font-size:clamp(17px,2vw,19px);color:var(--ink-2);max-width:720px;margin:0 0 22px}
.hero-actions{display:flex;flex-wrap:wrap;gap:12px;align-items:center}
.trust{display:flex;flex-wrap:wrap;gap:8px 22px;margin:22px 0 0;padding:0;list-style:none;color:var(--muted);font-size:14px}
.trust li{display:flex;gap:7px;align-items:center}
.trust li:before{content:"";width:16px;height:16px;border-radius:50%;background:var(--ok-soft) url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 16 16'%3E%3Cpath d='M4 8.5l2.5 2.5L12 5.5' fill='none' stroke='%23067647' stroke-width='2' stroke-linecap='round' stroke-linejoin='round'/%3E%3C/svg%3E") center/12px no-repeat;flex:none}
.byline{font-size:13.5px;color:var(--muted);margin-top:14px}

/* buttons */
.btn{display:inline-flex;align-items:center;justify-content:center;gap:8px;background:var(--brand);color:#fff;text-decoration:none;padding:12px 18px;border-radius:11px;font-weight:700;font-size:15.5px;border:0;cursor:pointer;line-height:1.2;transition:background .15s,transform .05s}
.btn:hover{background:var(--brand-2);color:#fff}
.btn:active{transform:translateY(1px)}
.btn.ghost{background:#fff;color:var(--ink);border:1px solid var(--line)}
.btn.ghost:hover{border-color:#c4cfdc;color:var(--ink)}
.btn.small{padding:9px 13px;font-size:14px;border-radius:9px}
.btn.amber{background:var(--accent);color:#1f1300}
.btn.amber:hover{background:#d98a06;color:#1f1300}
.btn .ext{font-size:.9em;opacity:.85}

.paid{display:inline-block;font-size:11px;color:var(--muted);margin-left:7px;white-space:nowrap;vertical-align:middle}
.result .paid{color:#a9c2dd}
.result .pick .paid{color:var(--muted)}

/* sections */
.section{padding:52px 0}
.section.alt{background:#fff;border-top:1px solid var(--line);border-bottom:1px solid var(--line)}
.section-head{max-width:760px;margin-bottom:24px}
.section-head p{color:var(--ink-2);margin:0}
.grid-2{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:20px}
.grid-3{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:20px}
.card{background:var(--card);border:1px solid var(--line);border-radius:var(--radius);padding:24px;box-shadow:var(--shadow)}
.card p:last-child{margin-bottom:0}
.kicker{font-size:12px;font-weight:800;letter-spacing:.08em;text-transform:uppercase;color:var(--brand-2)}
.muted{color:var(--muted)}
.small{font-size:14px}
.tiny{font-size:12.5px}

/* calculator */
.calc{display:grid;grid-template-columns:minmax(0,1.25fr) minmax(0,.9fr);gap:22px;align-items:start}
.calc-panel{background:#fff;border:1px solid var(--line);border-radius:var(--radius);box-shadow:var(--shadow)}
.calc-panel>.ph{padding:18px 20px;border-bottom:1px solid var(--line);display:flex;justify-content:space-between;align-items:center;gap:12px;flex-wrap:wrap}
.calc-panel>.pb{padding:16px 20px}
.step{display:inline-flex;width:24px;height:24px;border-radius:50%;background:var(--navy);color:#fff;font-size:13px;font-weight:700;align-items:center;justify-content:center;margin-right:8px}
.presets{display:flex;flex-wrap:wrap;gap:8px}
.chip{border:1px solid var(--line);background:#fff;border-radius:999px;padding:7px 12px;font:inherit;font-size:13.5px;cursor:pointer;color:var(--ink-2)}
.chip:hover{border-color:var(--brand);color:var(--brand-2)}
.chip[aria-pressed=true]{background:var(--brand-soft);border-color:var(--brand);color:var(--brand-2);font-weight:650}
.dev-table{width:100%;border-collapse:collapse;font-size:14.5px}
.dev-table th{font-size:12px;text-transform:uppercase;letter-spacing:.05em;color:var(--muted);text-align:left;font-weight:700;padding:6px 6px;border-bottom:1px solid var(--line)}
.dev-table td{padding:7px 6px;border-bottom:1px solid #eef2f7;vertical-align:middle}
.dev-table tr.on{background:#f3fbf8}
.dev-table .name{display:flex;gap:9px;align-items:center}
.dev-table .name input{width:18px;height:18px;accent-color:var(--brand);flex:none}
.dev-table .name small{display:block;color:var(--muted);font-size:12px;line-height:1.3}
.num{width:72px;padding:7px 8px;border:1px solid #cfd8e3;border-radius:8px;font:inherit;font-size:14px;background:#fff}
.num.qty{width:54px}
.num:focus,.sel:focus,.txt:focus{outline:2px solid #9fd8c9;border-color:var(--brand)}
.sel,.txt{padding:8px 10px;border:1px solid #cfd8e3;border-radius:8px;font:inherit;font-size:14.5px;background:#fff}
.txt{width:100%}
.settings{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:14px}
.settings label{display:block;font-weight:650;font-size:14px;margin-bottom:4px}
.settings .hint{font-size:12.5px;color:var(--muted);margin-top:3px}
.add-row{display:flex;gap:8px;flex-wrap:wrap;margin-top:12px}
.add-row .txt{flex:1 1 160px;width:auto}
.result{position:sticky;top:84px;background:var(--navy);color:#fff;border-radius:var(--radius);padding:22px;box-shadow:var(--shadow)}
.result .label{font-size:12px;letter-spacing:.08em;text-transform:uppercase;color:#a9c2dd;font-weight:700}
.result .big{font-size:46px;font-weight:800;letter-spacing:-1.5px;line-height:1.1;margin:6px 0 2px}
.result .sub{color:#c9d8ea;font-size:14px;margin:0 0 14px}
.metrics{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:10px;margin:14px 0}
.metric{background:rgba(255,255,255,.07);border-radius:10px;padding:10px 12px}
.metric span{display:block;font-size:12px;color:#a9c2dd}
.metric b{font-size:19px}
.warn{background:rgba(245,158,11,.14);border:1px solid rgba(245,158,11,.4);color:#ffe2a8;border-radius:10px;padding:10px 12px;font-size:13.5px;margin:10px 0}
.pick{background:#fff;color:var(--ink);border-radius:12px;padding:14px;margin-top:12px}
.pick .tag{display:inline-block;font-size:11.5px;font-weight:800;letter-spacing:.06em;text-transform:uppercase;color:var(--brand-2);background:var(--brand-soft);border-radius:6px;padding:3px 7px}
.pick h4{margin:6px 0 2px;font-size:17px}
.pick .specs{font-size:13.5px;color:var(--muted);margin:0 0 10px}
.pick .row{display:flex;gap:8px;flex-wrap:wrap;align-items:center;justify-content:space-between}
.result .fine{font-size:12px;color:#a9c2dd;margin:12px 0 0}
.result a{color:#bfe9dc}

/* comparison */
.table-wrap{overflow-x:auto;border:1px solid var(--line);border-radius:var(--radius);background:#fff;box-shadow:var(--shadow)}
table.compare{width:100%;border-collapse:collapse;min-width:860px;font-size:14.5px}
table.compare th,table.compare td{padding:12px 14px;border-bottom:1px solid #eef2f7;text-align:left;vertical-align:top}
table.compare thead th{background:#f8fafc;font-size:12px;text-transform:uppercase;letter-spacing:.05em;color:var(--muted)}
table.compare tbody tr:hover{background:#fafcfe}
table.compare td.model b{display:block;font-size:15.5px}
table.compare td.model small{color:var(--muted)}
.badge{display:inline-block;font-size:11.5px;font-weight:700;padding:3px 8px;border-radius:999px;background:var(--brand-soft);color:var(--brand-2);margin-top:4px}
.badge.amber{background:var(--accent-soft);color:#8a5300}
.filter-row{display:flex;flex-wrap:wrap;gap:8px;margin:0 0 14px}

/* product cards */
.prod{display:flex;flex-direction:column}
.prod .top{display:flex;justify-content:space-between;align-items:flex-start;gap:10px}
.prod dl{display:grid;grid-template-columns:auto 1fr;gap:4px 12px;font-size:14px;margin:12px 0}
.prod dt{color:var(--muted)}
.prod dd{margin:0;font-weight:600}
.prod .pc{display:grid;grid-template-columns:1fr 1fr;gap:12px;font-size:14px}
.prod .pc ul{margin:4px 0 0;padding-left:18px}
.prod .cta{margin-top:auto;padding-top:14px;display:flex;gap:10px;flex-wrap:wrap;align-items:center}

/* article */
.article h2{margin-top:38px}
.article h3{margin-top:26px}
.article p,.article li{color:var(--ink-2)}
.article table{width:100%;border-collapse:collapse;font-size:15px;margin:14px 0;background:#fff}
.article th,.article td{border:1px solid var(--line);padding:9px 11px;text-align:left}
.article th{background:#f8fafc}
.callout{background:var(--brand-soft);border:1px solid #bfe3d8;border-radius:12px;padding:14px 16px;margin:18px 0}
.callout.amber{background:var(--accent-soft);border-color:#fde1a1}
.callout.red{background:var(--danger-soft);border-color:#fecdca}
.formula{font-family:ui-monospace,SFMono-Regular,Menlo,monospace;background:#0f2a47;color:#e6f0fa;border-radius:10px;padding:12px 14px;font-size:14.5px;overflow-x:auto}
.toc{background:#fff;border:1px solid var(--line);border-radius:12px;padding:14px 18px;font-size:14.5px}
.toc ol{margin:6px 0 0;padding-left:20px}

/* faq */
.faq details{background:#fff;border:1px solid var(--line);border-radius:12px;padding:14px 18px;margin:10px 0}
.faq summary{cursor:pointer;font-weight:700;list-style:none;display:flex;justify-content:space-between;gap:12px}
.faq summary::-webkit-details-marker{display:none}
.faq summary:after{content:"+";font-weight:800;color:var(--brand)}
.faq details[open] summary:after{content:"–"}
.faq details p{color:var(--ink-2);margin:10px 0 0}

/* guides */
.guide-card{text-decoration:none;color:inherit;display:block;transition:border-color .15s,transform .15s}
.guide-card:hover{border-color:#a7d7c9;transform:translateY(-2px);color:inherit}
.guide-card .more{color:var(--brand-2);font-weight:700;font-size:14px}

/* footer */
.site-footer{background:#0b1b2e;color:#b8c6d6;padding:44px 0 28px;font-size:14px;margin-top:20px}
.site-footer a{color:#dbe7f3;text-decoration:none}
.site-footer a:hover{text-decoration:underline}
.footer-grid{display:grid;grid-template-columns:1.4fr 1fr 1fr;gap:28px}
.footer-grid h4{color:#fff;margin:0 0 10px;font-size:14px;text-transform:uppercase;letter-spacing:.06em}
.footer-grid ul{list-style:none;margin:0;padding:0}
.footer-grid li{margin:6px 0}
.legal{border-top:1px solid #1f3550;margin-top:28px;padding-top:18px;font-size:12.5px;color:#8ea2b8}

/* forms */
.form label{display:block;font-weight:650;margin:12px 0 4px}
.form textarea{min-height:140px;resize:vertical}
.hp{position:absolute;left:-5000px}

@media (max-width:900px){
  .calc{grid-template-columns:minmax(0,1fr)}
  .result{position:static}
  .grid-3{grid-template-columns:1fr 1fr}
  .footer-grid{grid-template-columns:1fr 1fr}
}
@media (max-width:720px){
  .nav-links{display:none;position:absolute;top:64px;left:0;right:0;background:#fff;flex-direction:column;align-items:flex-start;padding:12px 20px 18px;border-bottom:1px solid var(--line);gap:14px}
  .nav-links.open{display:flex}
  .menu-btn{display:inline-block}
  .grid-2,.grid-3,.settings,.prod .pc{grid-template-columns:1fr}
  .footer-grid{grid-template-columns:1fr}
  .hero{padding:38px 0 28px}
  .section{padding:38px 0}
  .dev-table th.h-hide,.dev-table td.h-hide{display:none}
  .num{width:58px;padding:7px 6px}
  .num.qty{width:46px}
  .dev-table td,.dev-table th{padding:6px 3px}
  .calc-panel>.pb,.calc-panel>.ph{padding-left:14px;padding-right:14px}
  .result .big{font-size:40px}
}
@media print{.site-header,.disclosure-bar,.site-footer,.btn{display:none!important}}