:root{--g:#1f6f5c;--g2:#e8f3ef;--ink:#1d2430;--mut:#5b6573;--line:#dfe4ea;--bg:#fafbfc;--r:12px}
[hidden]{display:none!important}
*{box-sizing:border-box}html{-webkit-text-size-adjust:100%}
body{margin:0;font:17px/1.65 system-ui,-apple-system,"Segoe UI",Roboto,Helvetica,Arial,sans-serif;color:var(--ink);background:var(--bg)}
.wrap{max-width:960px;margin:0 auto;padding:0 18px}
a{color:var(--g)}a:hover{text-decoration-thickness:2px}
h1{font-size:2rem;line-height:1.2;margin:.4em 0 .3em}h2{font-size:1.4rem;margin:1.8em 0 .5em;line-height:1.3}h3{font-size:1.1rem;margin:1.3em 0 .4em}
.site-header{background:#fff;border-bottom:1px solid var(--line);position:sticky;top:0;z-index:5}
.site-header .wrap{display:flex;align-items:center;justify-content:space-between;min-height:58px;gap:12px;flex-wrap:wrap}
.brand{display:flex;align-items:center;gap:8px;font-weight:700;color:var(--ink);text-decoration:none;font-size:1.1rem}
.main-nav a{margin-left:16px;text-decoration:none;color:var(--ink);font-weight:500}.main-nav a:hover{color:var(--g)}
.crumbs{font-size:.85rem;color:var(--mut);margin-top:16px}
.lead{font-size:1.15rem;color:var(--mut);max-width:720px}
.hero{padding:34px 0 10px}.hero h1{font-size:2.3rem}
.cards{display:grid;grid-template-columns:repeat(auto-fill,minmax(250px,1fr));gap:14px;margin:18px 0}
.card{display:block;background:#fff;border:1px solid var(--line);border-radius:var(--r);padding:18px;text-decoration:none;color:var(--ink);transition:.15s}
.card:hover{border-color:var(--g);box-shadow:0 4px 18px rgba(31,111,92,.12);transform:translateY(-2px)}
.card h3{margin:.3em 0 .2em;color:var(--g)}.card p{margin:0;color:var(--mut);font-size:.95rem}.card .ico{font-size:1.7rem}
.tool{display:grid;grid-template-columns:1.2fr 1fr;gap:18px;background:#fff;border:1px solid var(--line);border-radius:var(--r);padding:20px;margin:18px 0}
@media (max-width:720px){.tool{grid-template-columns:1fr}h1,.hero h1{font-size:1.7rem}.main-nav a{margin:0 14px 0 0}}
form label{display:block;font-size:.9rem;font-weight:600;margin-bottom:10px}
form input[type=number],form select{display:block;width:100%;margin-top:4px;padding:10px 12px;font:inherit;border:1px solid #c9d1da;border-radius:8px;background:#fff}
form input:focus,form select:focus{outline:2px solid var(--g);border-color:var(--g)}
label.check{display:flex;gap:8px;align-items:center;font-weight:500}
.grid2{display:grid;grid-template-columns:1fr 1fr;gap:0 12px}
button{font:inherit;font-weight:600;border:0;border-radius:8px;padding:11px 18px;cursor:pointer;background:var(--g);color:#fff}
button.secondary{background:var(--g2);color:var(--g);margin-right:8px}
.result{background:var(--g2);border-radius:var(--r);padding:16px;align-self:start}
.result.err{background:#fdecec;color:#8a1c1c}
.res-row{display:flex;justify-content:space-between;gap:10px;padding:7px 0;border-bottom:1px dashed #c3ddd4;font-size:.95rem}
.res-row:last-child{border:0}.res-main{font-size:1.15rem}.res-main b{color:var(--g);font-size:1.35rem}
.note{font-size:.88rem;color:var(--mut)}
table{border-collapse:collapse;width:100%;margin:12px 0;font-size:.95rem;background:#fff}
th,td{border:1px solid var(--line);padding:8px 10px;text-align:left}th{background:var(--g2)}
.tbl{overflow-x:auto}
.formula{background:#fff;border-left:4px solid var(--g);padding:10px 14px;font-family:ui-monospace,Consolas,monospace;font-size:.92rem;overflow-x:auto}
.faq details{background:#fff;border:1px solid var(--line);border-radius:8px;padding:10px 14px;margin:8px 0}
.faq summary{font-weight:600;cursor:pointer}
.related ul,.guide-list{padding-left:18px}.related li{margin:4px 0}
.guide-list li{margin:0 0 14px}
.ad-slot{margin:22px 0;min-height:0}.ad-empty{display:none}
.site-footer{background:#fff;border-top:1px solid var(--line);margin-top:50px;padding:26px 0 18px;font-size:.92rem}
.foot-cols{display:grid;grid-template-columns:2fr 1.4fr 1fr;gap:20px}.foot-cols ul{list-style:none;padding:0;margin:6px 0}
.foot-cols li{margin:3px 0}.foot-cols p{color:var(--mut)}
@media (max-width:720px){.foot-cols{grid-template-columns:1fr}}
.copy{color:var(--mut);font-size:.85rem}
article{max-width:760px}