:root{--ink:#1d2330;--muted:#5b6475;--line:#e3e6ee;--bg:#f5f6fa;--card:#fff;--brand:#6b4fbb;--brand-d:#553c9a;--brand-l:#f1edfb;--ok:#1f7a4d;--warn:#9a3412;--r:14px}
*{box-sizing:border-box}
html{-webkit-text-size-adjust:100%}
body{margin:0;font:16px/1.6 system-ui,-apple-system,"Segoe UI",Roboto,"Helvetica Neue",Arial,sans-serif;color:var(--ink);background:var(--bg)}
a{color:var(--brand-d)}
a:hover{color:var(--brand)}
img,svg{max-width:100%}
.wrap{max-width:1080px;margin:0 auto;padding:0 18px}
.skip{position:absolute;left:-999px}.skip:focus{left:8px;top:8px;background:#fff;padding:8px;z-index:9}

.top{background:linear-gradient(120deg,#667eea,#764ba2);color:#fff}
.top .wrap{display:flex;align-items:center;justify-content:space-between;gap:14px;min-height:60px;flex-wrap:wrap}
.logo{display:flex;align-items:center;gap:10px;color:#fff;text-decoration:none;font-weight:700;font-size:1.15rem}
.logo:hover{color:#fff}
.logo svg{width:30px;height:30px}
.nav{display:flex;flex-wrap:wrap;gap:2px}
.nav a{color:#fff;text-decoration:none;padding:6px 10px;border-radius:8px;font-size:.95rem}
.nav a:hover,.nav a[aria-current]{background:rgba(255,255,255,.18);color:#fff}

.crumbs{font-size:.85rem;color:var(--muted);margin:18px 0 6px}
.crumbs ol{list-style:none;margin:0;padding:0;display:flex;flex-wrap:wrap;gap:6px}
.crumbs li+li:before{content:"›";margin-right:6px;color:#9aa1b1}
.crumbs a{color:var(--muted)}
h1{font-size:clamp(1.6rem,4vw,2.2rem);line-height:1.2;margin:4px 0 8px}
.lead{color:var(--muted);margin:0 0 20px;max-width:760px}
h2{font-size:1.35rem;line-height:1.3;margin:30px 0 10px}
h3{font-size:1.08rem;margin:20px 0 6px}

.calc{display:grid;grid-template-columns:minmax(0,5fr) minmax(0,6fr);gap:18px;align-items:start}
@media(max-width:820px){.calc{grid-template-columns:1fr}}
.card{background:var(--card);border:1px solid var(--line);border-radius:var(--r);padding:20px}
.fields{display:grid;gap:14px}
.f label{display:block;font-weight:600;font-size:.92rem;margin-bottom:5px}
.f .hint{display:block;font-weight:400;color:var(--muted);font-size:.8rem;margin-top:3px}
.inp{position:relative;display:flex}
.inp input,.inp select,.f textarea{width:100%;font:inherit;color:inherit;padding:10px 12px;border:1.5px solid #cfd4de;border-radius:10px;background:#fff;min-height:44px}
.f textarea{min-height:110px;resize:vertical}
.inp .u{display:flex;align-items:center;padding:0 12px;border:1.5px solid #cfd4de;border-left:0;border-radius:0 10px 10px 0;background:#f3f4f8;color:var(--muted);font-size:.9rem;white-space:nowrap}
.inp.has-u input{border-radius:10px 0 0 10px}
input:focus,select:focus,textarea:focus{outline:none;border-color:var(--brand);box-shadow:0 0 0 3px rgba(107,79,187,.18)}
.chk{display:flex;gap:8px;align-items:center;font-weight:600;font-size:.92rem}
.chk input{width:18px;height:18px}
.btn{margin-top:16px;width:100%;font:inherit;font-weight:700;color:#fff;background:var(--brand);border:0;border-radius:10px;padding:12px;cursor:pointer;min-height:46px}
.btn:hover{background:var(--brand-d)}
.result h2{margin:0 0 12px;font-size:1.1rem}
.rows{margin:0}
.rows div{display:flex;justify-content:space-between;gap:12px;padding:9px 0;border-bottom:1px solid var(--line)}
.rows div:last-child{border-bottom:0}
.rows dt{color:var(--muted)}
.rows dd{margin:0;font-weight:700;text-align:right;font-variant-numeric:tabular-nums;overflow-wrap:anywhere}
.rows div.main{background:var(--brand-l);border:0;border-radius:10px;padding:12px 14px;margin-bottom:6px;flex-wrap:wrap}
.rows div.main dt{color:var(--brand-d);font-weight:600}
.rows div.main dd{font-size:1.45rem;color:var(--brand-d)}
.msg{color:var(--warn);font-weight:600}
.note{color:var(--muted);font-size:.88rem;margin:12px 0 0}
.tbl{overflow-x:auto;margin-top:14px}
table{border-collapse:collapse;width:100%;font-size:.9rem;font-variant-numeric:tabular-nums}
th,td{padding:7px 9px;border-bottom:1px solid var(--line);text-align:right;white-space:nowrap}
th:first-child,td:first-child{text-align:left}
thead th{background:#f3f4f8;font-weight:600}
details summary{cursor:pointer;font-weight:600;color:var(--brand-d);margin-top:12px}

.content{max-width:780px}
.content p,.content li{color:#2d3444}
.formula{background:#fff;border:1px solid var(--line);border-left:4px solid var(--brand);border-radius:10px;padding:14px 16px;margin:12px 0;overflow-x:auto}
.formula code{font:600 1.02rem/1.5 ui-monospace,SFMono-Regular,Menlo,Consolas,monospace;white-space:pre}
.formula dl{margin:10px 0 0;font-size:.92rem}
.formula dt{display:inline;font-weight:700}
.formula dd{display:inline;margin:0}
.formula dd:after{content:"";display:block}
.example{display:grid;grid-template-columns:1fr 1fr;gap:12px}
@media(max-width:620px){.example{grid-template-columns:1fr}}
.example .card{padding:14px 16px}
.example h3{margin:0 0 6px;font-size:.95rem;color:var(--muted)}
.example ul{margin:0;padding-left:18px}
.faq details{background:#fff;border:1px solid var(--line);border-radius:10px;padding:12px 16px;margin:8px 0}
.faq summary{margin:0;color:var(--ink)}
.faq details p{margin:8px 0 0}
.links{display:grid;grid-template-columns:repeat(auto-fill,minmax(220px,1fr));gap:8px;list-style:none;padding:0;margin:10px 0}
.links a{display:block;background:#fff;border:1px solid var(--line);border-radius:10px;padding:10px 12px;text-decoration:none;color:var(--ink)}
.links a:hover{border-color:var(--brand);color:var(--brand-d)}
.links small{display:block;color:var(--muted);font-size:.8rem}

.hero{padding:26px 0 8px}
.search{display:flex;margin:14px 0 4px;max-width:560px}
.search input{width:100%;font:inherit;padding:12px 14px;border:1.5px solid #cfd4de;border-radius:10px;min-height:48px}
.cats{display:grid;grid-template-columns:repeat(auto-fill,minmax(230px,1fr));gap:12px;margin:18px 0}
.cats a{display:block;background:#fff;border:1px solid var(--line);border-radius:var(--r);padding:16px;text-decoration:none;color:var(--ink)}
.cats a:hover{border-color:var(--brand)}
.cats strong{display:block;font-size:1.05rem}
.cats span{color:var(--muted);font-size:.9rem}
.group h3{margin-top:22px}
.empty{color:var(--muted)}

.foot{margin-top:50px;background:#1d2330;color:#c9cfdb;font-size:.92rem}
.foot .wrap{display:grid;grid-template-columns:repeat(auto-fit,minmax(180px,1fr));gap:18px;padding-top:28px;padding-bottom:20px}
.foot h2{color:#fff;font-size:.95rem;margin:0 0 8px}
.foot ul{list-style:none;margin:0;padding:0}
.foot li{margin:4px 0}
.foot a{color:#c9cfdb;text-decoration:none}
.foot a:hover{color:#fff;text-decoration:underline}
.foot .legal{grid-column:1/-1;border-top:1px solid #333b4b;padding-top:14px;color:#8d95a6;font-size:.85rem}
.calc>*{min-width:0}
.inp{min-width:0}
.inp input,.inp select{min-width:0;text-overflow:ellipsis}
.content table{display:block;overflow-x:auto;margin:12px 0}
.content th,.content td{white-space:normal;text-align:left;vertical-align:top}