:root{
  --bg:#f7f6f2;--surface:#ffffff;--fg:#1c2230;--muted:#5b6475;--line:#e2dfd6;
  --accent:#1e6b52;--accent-ink:#ffffff;--accent-soft:#e3f1ea;--warn:#a5481d;
  --result-bg:#0f2a22;--result-fg:#eafff5;--radius:14px;
}
@media (prefers-color-scheme:dark){:root:not([data-theme="light"]){
  --bg:#10141c;--surface:#181e2a;--fg:#eceff4;--muted:#a2abbd;--line:#2a3243;
  --accent:#3fbf91;--accent-ink:#06140f;--accent-soft:#16302a;--warn:#f0a070;
  --result-bg:#0c231c;--result-fg:#eafff5;
}}
*{box-sizing:border-box}
html{-webkit-text-size-adjust:100%}
body{margin:0;background:var(--bg);color:var(--fg);font:16px/1.65 system-ui,-apple-system,"Segoe UI",Roboto,Helvetica,Arial,sans-serif}
a{color:var(--accent)}
img{max-width:100%;height:auto}
.wrap{max-width:960px;margin:0 auto;padding:0 16px}

/* header */
.site-head{background:var(--surface);border-bottom:1px solid var(--line);position:sticky;top:0;z-index:5}
.site-head .wrap{display:flex;align-items:center;gap:18px;min-height:58px;flex-wrap:wrap}
.logo{display:flex;align-items:center;gap:8px;text-decoration:none;color:var(--fg);font-weight:800;font-size:19px;letter-spacing:-.01em}
.logo svg{width:28px;height:28px}
.logo b{color:var(--accent)}
.nav{display:flex;gap:4px;flex-wrap:wrap;margin-left:auto}
.nav a{color:var(--muted);text-decoration:none;font-size:14.5px;padding:6px 10px;border-radius:8px}
.nav a:hover{background:var(--accent-soft);color:var(--fg)}
.nav a[aria-current="page"]{color:var(--accent);font-weight:700}
@media (max-width:720px){.nav{margin-left:0;width:100%;overflow-x:auto;flex-wrap:nowrap;padding-bottom:8px}.nav a{white-space:nowrap}}

/* page */
.crumbs{font-size:13.5px;color:var(--muted);margin:18px 0 0}
.crumbs a{color:var(--muted)}
h1{font-size:clamp(27px,4.6vw,38px);line-height:1.15;margin:8px 0 8px;letter-spacing:-.02em}
.lead{color:var(--muted);margin:0 0 20px;max-width:720px;font-size:17px}

/* calculator card */
.calc{display:grid;grid-template-columns:minmax(0,1.35fr) minmax(0,1fr);gap:18px;align-items:start}
@media (max-width:820px){.calc{grid-template-columns:1fr}}
.card{background:var(--surface);border:1px solid var(--line);border-radius:var(--radius);padding:18px;box-shadow:0 1px 2px rgba(0,0,0,.03),0 6px 20px rgba(0,0,0,.04)}
.card h2{font-size:16px;margin:0 0 12px;text-transform:uppercase;letter-spacing:.06em;color:var(--muted)}
.grid{display:grid;grid-template-columns:repeat(auto-fit,minmax(130px,1fr));gap:12px}
.field{display:flex;flex-direction:column;gap:5px}
.field label{font-size:13.5px;font-weight:600;color:var(--muted)}
.field .in{display:flex;align-items:stretch;border:1px solid var(--line);border-radius:10px;background:var(--bg);overflow:hidden}
.field .in:focus-within{border-color:var(--accent);box-shadow:0 0 0 3px var(--accent-soft)}
.field input,.field select{font:inherit;font-size:17px;border:0;background:transparent;color:var(--fg);padding:10px 12px;width:100%;min-width:0;outline:none}
.field select{cursor:pointer}
.field .unit{display:flex;align-items:center;padding:0 10px;color:var(--muted);font-size:14px;border-left:1px solid var(--line);white-space:nowrap}
.seg{display:flex;flex-wrap:wrap;gap:6px;margin-bottom:14px}
.seg button{font:inherit;font-size:14px;border:1px solid var(--line);background:var(--bg);color:var(--fg);padding:7px 12px;border-radius:999px;cursor:pointer}
.seg button[aria-pressed="true"]{background:var(--accent);border-color:var(--accent);color:var(--accent-ink);font-weight:700}
.row-item{border:1px dashed var(--line);border-radius:12px;padding:12px;margin-bottom:10px;position:relative}
.row-item .row-title{font-weight:700;font-size:14px;margin-bottom:8px;display:flex;justify-content:space-between;align-items:center;gap:8px}
.btn{font:inherit;font-weight:700;border:0;border-radius:10px;padding:10px 16px;cursor:pointer;background:var(--accent);color:var(--accent-ink)}
.btn.ghost{background:transparent;color:var(--accent);border:1px solid var(--accent)}
.btn.small{padding:5px 10px;font-size:13px}
.btn.link{background:none;color:var(--warn);padding:2px 6px;font-weight:600;font-size:13px}
details.more{margin-top:14px;border-top:1px solid var(--line);padding-top:10px}
details.more summary{cursor:pointer;font-weight:700;color:var(--accent);font-size:14.5px}
details.more[open] summary{margin-bottom:10px}

/* results */
.result{background:var(--result-bg);color:var(--result-fg);border-radius:var(--radius);padding:18px;position:sticky;top:72px}
.result .big{font-size:clamp(34px,6vw,46px);font-weight:800;line-height:1.05;letter-spacing:-.02em}
.result .big small{font-size:18px;font-weight:600;opacity:.8;margin-left:4px}
.result .label{font-size:13px;text-transform:uppercase;letter-spacing:.08em;opacity:.75;margin-bottom:4px}
.result dl{display:grid;grid-template-columns:1fr auto;gap:6px 12px;margin:16px 0 0;font-size:15px}
.result dt{opacity:.8}
.result dd{margin:0;font-weight:700;text-align:right;font-variant-numeric:tabular-nums}
.result .note{font-size:13px;opacity:.75;margin-top:14px}
.result .actions{display:flex;gap:8px;margin-top:14px;flex-wrap:wrap}
.result .actions .btn{background:rgba(255,255,255,.12);color:var(--result-fg);font-size:13px;padding:7px 12px}

/* content */
.ad-slot{margin:22px 0;min-height:0}
.content{max-width:760px;margin:36px 0 10px}
.content h2{font-size:24px;line-height:1.25;margin:34px 0 10px;letter-spacing:-.01em}
.content h3{font-size:18px;margin:22px 0 6px}
.content p,.content li{color:var(--fg)}
.content table{border-collapse:collapse;width:100%;margin:12px 0;font-size:15px}
.content th,.content td{border:1px solid var(--line);padding:8px 10px;text-align:left}
.content th{background:var(--accent-soft)}
.formula{background:var(--surface);border:1px solid var(--line);border-left:4px solid var(--accent);padding:12px 14px;border-radius:8px;font-family:ui-monospace,Menlo,Consolas,monospace;font-size:14.5px;overflow-x:auto}
.faq details{border:1px solid var(--line);background:var(--surface);border-radius:10px;padding:12px 14px;margin:8px 0}
.faq summary{cursor:pointer;font-weight:700}
.faq details p{margin:8px 0 0}
.related{display:grid;grid-template-columns:repeat(auto-fit,minmax(200px,1fr));gap:12px;margin:14px 0 0}
.related a{display:block;text-decoration:none;color:var(--fg);background:var(--surface);border:1px solid var(--line);border-radius:12px;padding:14px}
.related a:hover{border-color:var(--accent)}
.related b{display:block;color:var(--accent);margin-bottom:2px}
.related span{font-size:14px;color:var(--muted)}

/* hub */
.hero{padding:26px 0 8px}
.tools{display:grid;grid-template-columns:repeat(auto-fit,minmax(250px,1fr));gap:14px;margin:18px 0 10px}
.tools a{display:flex;flex-direction:column;gap:6px;text-decoration:none;color:var(--fg);background:var(--surface);border:1px solid var(--line);border-radius:var(--radius);padding:18px;transition:border-color .15s,transform .15s}
.tools a:hover{border-color:var(--accent);transform:translateY(-2px)}
.tools .ico{font-size:28px}
.tools b{font-size:18px}
.tools span{color:var(--muted);font-size:14.5px}

/* footer */
.site-foot{border-top:1px solid var(--line);margin-top:48px;padding:24px 0 32px;color:var(--muted);font-size:14px;background:var(--surface)}
.site-foot .wrap{display:flex;gap:18px;flex-wrap:wrap;justify-content:space-between;align-items:center}
.site-foot nav{display:flex;gap:14px;flex-wrap:wrap}
.site-foot a{color:var(--muted)}
.studio{display:flex;align-items:center;gap:8px}
.studio img{height:26px;width:auto;background:#0b1226;border-radius:6px;padding:4px 8px}
.legal{max-width:760px}
.legal h2{font-size:20px;margin-top:26px}