:root{
  --bg:#f7f6f3;--surface:#ffffff;--text:#1d232b;--muted:#5b6470;--line:#e3e0da;
  --accent:#d9480f;--accent-ink:#ffffff;--accent-soft:#fff0e8;--ok:#2b8a3e;
  --radius:14px;--shadow:0 1px 2px rgba(20,24,30,.06),0 4px 16px rgba(20,24,30,.06);
  --maxw:1080px;
}
@media (prefers-color-scheme:dark){
  :root{--bg:#121417;--surface:#1b1f24;--text:#e8eaed;--muted:#a0a8b3;--line:#2c323a;
    --accent:#ff7a3d;--accent-ink:#1b1f24;--accent-soft:#2a1d16;--shadow:none}
}
*{box-sizing:border-box}
html{-webkit-text-size-adjust:100%}
body{margin:0;background:var(--bg);color:var(--text);
  font:16px/1.6 system-ui,-apple-system,"Segoe UI",Roboto,"Helvetica Neue",Arial,sans-serif}
a{color:var(--accent)}
a:hover{text-decoration-thickness:2px}
img,svg{max-width:100%}
.wrap{max-width:var(--maxw);margin:0 auto;padding:0 16px}

/* Header / footer */
.site-header{background:var(--surface);border-bottom:1px solid var(--line)}
.site-header .wrap{display:flex;align-items:center;justify-content:space-between;gap:12px;min-height:60px;flex-wrap:wrap}
.brand{display:flex;align-items:center;gap:10px;font-weight:800;font-size:1.1rem;color:var(--text);text-decoration:none}
.brand svg{width:28px;height:28px}
.nav{display:flex;gap:4px;flex-wrap:wrap}
.nav a{color:var(--muted);text-decoration:none;padding:6px 10px;border-radius:8px;font-size:.95rem}
.nav a:hover,.nav a[aria-current="page"]{background:var(--accent-soft);color:var(--accent)}
.site-footer{margin-top:56px;border-top:1px solid var(--line);background:var(--surface);color:var(--muted);font-size:.92rem}
.site-footer .wrap{padding-top:24px;padding-bottom:28px;display:grid;gap:14px}
.site-footer nav{display:flex;flex-wrap:wrap;gap:6px 16px}
.site-footer a{color:var(--muted)}

/* Typography */
h1{font-size:clamp(1.7rem,3.6vw,2.4rem);line-height:1.2;margin:28px 0 10px;letter-spacing:-.01em}
h2{font-size:1.35rem;margin:36px 0 10px;line-height:1.3}
h3{font-size:1.08rem;margin:22px 0 6px}
.lead{font-size:1.08rem;color:var(--muted);max-width:760px;margin:0 0 20px}
.crumbs{font-size:.88rem;color:var(--muted);margin-top:18px}
.crumbs a{color:var(--muted)}

/* Home */
.hero{padding:28px 0 8px}
.cards{display:grid;grid-template-columns:repeat(auto-fill,minmax(240px,1fr));gap:14px;margin:18px 0}
.card{display:block;background:var(--surface);border:1px solid var(--line);border-radius:var(--radius);padding:18px;text-decoration:none;color:var(--text);box-shadow:var(--shadow);transition:transform .12s ease,border-color .12s ease}
.card:hover{transform:translateY(-2px);border-color:var(--accent)}
.card .ico{width:40px;height:40px;border-radius:10px;background:var(--accent-soft);color:var(--accent);display:grid;place-items:center;font-size:1.3rem;margin-bottom:10px}
.card h3{margin:0 0 4px;font-size:1.05rem}
.card p{margin:0;color:var(--muted);font-size:.93rem}

/* Calculator layout */
.calc-grid{display:grid;grid-template-columns:minmax(0,1.15fr) minmax(0,.85fr);gap:18px;align-items:start}
@media (max-width:820px){.calc-grid{grid-template-columns:1fr}}
.panel{background:var(--surface);border:1px solid var(--line);border-radius:var(--radius);padding:18px;box-shadow:var(--shadow)}
.result-panel{position:sticky;top:12px}
@media (max-width:820px){.result-panel{position:static}}
fieldset{border:0;padding:0;margin:0 0 14px}
legend{font-weight:700;margin-bottom:8px;font-size:.95rem}
.seg{display:inline-flex;background:var(--bg);border:1px solid var(--line);border-radius:10px;padding:3px;gap:3px;flex-wrap:wrap}
.seg input{position:absolute;opacity:0;pointer-events:none}
.seg label{padding:7px 12px;border-radius:8px;cursor:pointer;font-size:.92rem;color:var(--muted);user-select:none}
.seg input:checked+label{background:var(--surface);color:var(--text);box-shadow:var(--shadow);font-weight:600}
.seg input:focus-visible+label{outline:2px solid var(--accent);outline-offset:1px}
.fields{display:grid;grid-template-columns:repeat(auto-fill,minmax(150px,1fr));gap:12px}
.field label{display:block;font-size:.88rem;color:var(--muted);margin-bottom:4px}
.field .unit{color:var(--text);font-weight:600}
input[type=number],select{width:100%;padding:10px 12px;border:1px solid var(--line);border-radius:10px;background:var(--bg);color:var(--text);font:inherit}
input[type=number]:focus,select:focus{outline:2px solid var(--accent);outline-offset:0;border-color:transparent}
.check{display:flex;gap:8px;align-items:center;font-size:.95rem;margin-top:4px}
.check input{width:18px;height:18px;accent-color:var(--accent)}
.btn{display:inline-block;background:var(--accent);color:var(--accent-ink);border:0;border-radius:10px;padding:11px 18px;font:inherit;font-weight:700;cursor:pointer;margin-top:6px}
.btn:hover{filter:brightness(1.05)}
.r-big{display:flex;flex-direction:column;padding:6px 0 12px;border-bottom:1px solid var(--line);margin-bottom:8px}
.r-num{font-size:2.1rem;font-weight:800;color:var(--accent);line-height:1.15}
.r-lbl{color:var(--muted);font-size:.92rem}
.r-row{display:flex;justify-content:space-between;gap:12px;padding:8px 0;border-bottom:1px dashed var(--line);font-size:.95rem}
.r-row:last-child{border-bottom:0}
.r-row span{color:var(--muted)}
.note{font-size:.85rem;color:var(--muted);margin:12px 0 0}

/* Article content */
.content{max-width:760px}
.content p,.content li{color:var(--text)}
.content code,.formula{background:var(--accent-soft);border-radius:8px;padding:2px 6px;font-family:ui-monospace,SFMono-Regular,Menlo,Consolas,monospace;font-size:.92em}
.formula{display:block;padding:12px 14px;margin:10px 0;white-space:pre-wrap}
table.ref{border-collapse:collapse;width:100%;margin:10px 0;font-size:.95rem}
table.ref th,table.ref td{border-bottom:1px solid var(--line);padding:8px;text-align:left}
table.ref th{color:var(--muted);font-weight:600}
.faq details{border:1px solid var(--line);border-radius:10px;padding:10px 14px;margin:8px 0;background:var(--surface)}
.faq summary{cursor:pointer;font-weight:600}
.related{display:flex;flex-wrap:wrap;gap:8px;margin:8px 0}
.related a{border:1px solid var(--line);border-radius:999px;padding:6px 12px;text-decoration:none;background:var(--surface);font-size:.92rem}
.ad-slot{margin:24px 0;min-height:0}