*,*::before,*::after{box-sizing:border-box}
html{-webkit-text-size-adjust:100%}
body{margin:0;font-family:"DM Sans",system-ui,-apple-system,"Segoe UI",sans-serif;font-size:16px;line-height:1.6;color:#1f2328;background:#fff}
a{color:#1976d2;text-decoration:none}
a:hover{color:#0d5bb0;text-decoration:underline}
img,svg{display:block}
h1,h2,h3{line-height:1.2;margin:0;color:#1f2328;font-weight:600;letter-spacing:-.01em}
p{margin:0 0 14px;text-wrap:pretty}
.wrap{max-width:1320px;margin:0 auto;padding:0 24px}
.narrow{max-width:832px;margin:0 auto;padding:0 20px}
.ico{width:20px;height:20px;fill:none;stroke:currentColor;stroke-width:2;stroke-linecap:round;stroke-linejoin:round}
.skip{position:absolute;left:-999px;top:0;background:#1976d2;color:#fff;padding:8px 14px;z-index:99}
.skip:focus{left:8px}
/* header */
.site-header{position:sticky;top:0;z-index:50;background:#fff;box-shadow:0 2px 6px rgba(0,0,0,.12)}
.site-header .wrap{display:flex;align-items:center;gap:24px;min-height:64px;flex-wrap:wrap}
.brand{display:flex;align-items:center;gap:10px;font-weight:700;font-size:19px;color:#1f2328}
.brand:hover{text-decoration:none;color:#1f2328}
.brand .ico{width:28px;height:28px;color:#1976d2;stroke-width:1.6}
.hsearch{flex:1;max-width:450px;margin:0 auto;position:relative}
.hsearch input{width:100%;height:38px;border:0;border-radius:8px;background:#f3f4f6;padding:0 12px 0 38px;font:inherit;font-size:14px;color:#1f2328}
.hsearch input:focus,.field input:focus,.field select:focus,.field textarea:focus,.bigsearch input:focus{outline:2px solid #1976d2;outline-offset:1px}
.hsearch .ico,.bigsearch .ico{position:absolute;left:12px;top:50%;transform:translateY(-50%);width:16px;height:16px;color:#6b7280}
.sug{position:absolute;top:44px;left:0;right:0;background:#fff;border:1px solid #e5e7eb;border-radius:10px;box-shadow:0 8px 24px rgba(0,0,0,.1);list-style:none;margin:0;padding:6px;display:none;max-height:320px;overflow:auto}
.sug.open{display:block}
.sug a{display:block;padding:10px 12px;border-radius:6px;color:#1f2328;font-size:14px}
.sug a:hover,.sug a:focus{background:#eef5fc;text-decoration:none}
.sug .none{padding:10px 12px;font-size:14px;color:#6b7280}
.nav{display:flex;gap:6px}
.nav a{padding:8px 14px;border-radius:8px;color:#1f2328;font-size:15px;font-weight:500}
.nav a:hover{background:#f3f4f6;text-decoration:none}
.nav a[aria-current="page"]{background:#e3effb;color:#1976d2}
@media (max-width:760px){.site-header .wrap{gap:10px;padding-top:10px;padding-bottom:10px}.hsearch{order:3;flex-basis:100%;max-width:none}.nav{margin-left:auto;gap:2px}.nav a{padding:10px 10px;font-size:14.5px}}
@media (max-width:420px){.brand{font-size:17px}.brand .ico{width:24px;height:24px}.nav a{padding:10px 7px}}
/* hero */
.hero{background:linear-gradient(135deg,#eef4fc 0%,#fff 50%,#fdf6f0 100%);padding:72px 0 88px;text-align:center}
.hero h1{font-size:clamp(32px,5.5vw,60px);font-weight:700;letter-spacing:-.02em;max-width:1000px;margin:0 auto 18px;text-wrap:balance}
.hero p{font-size:19px;color:#4b5563;max-width:860px;margin:0 auto 32px;text-wrap:balance}
.bigsearch{max-width:760px;margin:0 auto;position:relative}
.bigsearch input{width:100%;height:48px;border:1px solid #d1d5db;border-radius:8px;padding:0 14px 0 40px;font:inherit;font-size:15px;box-shadow:0 2px 4px rgba(0,0,0,.06)}
/* grid */
.grid{display:grid;grid-template-columns:repeat(auto-fill,minmax(min(100%,300px),1fr));gap:20px}
#calc-grid{grid-template-columns:repeat(3,minmax(0,1fr));gap:24px}
@media (max-width:1000px){#calc-grid{grid-template-columns:repeat(2,minmax(0,1fr));gap:18px}}
@media (max-width:640px){#calc-grid{grid-template-columns:1fr;gap:14px}}
.grid.two{grid-template-columns:repeat(auto-fill,minmax(min(100%,280px),1fr))}
.card{border:1px solid #e5e7eb;border-radius:12px;padding:22px;display:flex;flex-direction:column;background:#fff;transition:box-shadow .15s,border-color .15s;color:inherit}
.card:hover{box-shadow:0 6px 18px rgba(25,118,210,.10);border-color:#cfe0f3;text-decoration:none;color:inherit}
.chip{width:42px;height:42px;border-radius:8px;background:#e8f1fb;color:#1976d2;display:grid;place-items:center;margin-bottom:18px}
.card h2,.card h3{font-size:18px;margin-bottom:8px}
.card p{font-size:14.5px;color:#5b6470;margin-bottom:16px;flex:1}
.more{display:inline-flex;align-items:center;gap:6px;color:#1976d2;font-size:15px;font-weight:500}
.more .ico{width:15px;height:15px}
.section{padding:64px 0}
.section.alt{background:#fafafa;border-top:1px solid #eee;border-bottom:1px solid #eee}
.muted{color:#5b6470}
.hidden{display:none!important}
/* calculator page */
.crumbs{font-size:14px;color:#6b7280;padding-top:28px;margin-bottom:14px}
.crumbs ol{list-style:none;display:flex;gap:8px;flex-wrap:wrap;margin:0;padding:0}
.crumbs li+li::before{content:"›";margin-right:8px;color:#9ca3af}
.calc-card{border:1px solid #e5e7eb;border-radius:14px;padding:32px;box-shadow:0 4px 14px rgba(0,0,0,.08);background:#fff}
.calc-head{display:flex;align-items:center;gap:14px;margin-bottom:24px}
.calc-head .chip{background:#1976d2;color:#fff;width:48px;height:48px;margin:0;flex:none}
.calc-head .ico{width:24px;height:24px}
.calc-head h1{font-size:clamp(24px,4vw,32px)}
.row{display:grid;gap:20px;grid-template-columns:repeat(var(--c,1),minmax(0,1fr));margin-bottom:18px}
@media (max-width:600px){.row{grid-template-columns:1fr}.calc-card{padding:22px}}
.field label{display:block;font-size:14px;font-weight:500;margin-bottom:8px}
.field input,.field select,.field textarea{width:100%;height:50px;border:1px solid #d9dde3;border-radius:8px;padding:0 16px;font:inherit;font-size:16px;color:#1f2328;background:#fff}
.field textarea{height:144px;padding:12px 16px;resize:vertical}
.hr{border:0;border-top:1px solid #e5e7eb;margin:0 0 18px}
.btn{display:block;width:100%;height:52px;border:0;border-radius:8px;background:#1976d2;color:#fff;font:inherit;font-weight:600;font-size:16px;cursor:pointer;margin-top:8px}
.btn:hover{background:#1565c0}
.btn.inline{display:inline-flex;width:auto;padding:0 26px;height:46px;align-items:center}
.btn.inline:hover{color:#fff;text-decoration:none}
.result{margin-top:22px;border-radius:10px;background:#eef5fc;border:1px solid #cfe0f3;padding:20px}
.result:empty{display:none}
.result .lbl{font-size:14px;color:#4b5563}
.result .val{font-size:34px;font-weight:700;color:#1976d2;line-height:1.2;margin:4px 0 8px}
.result ul{margin:0;padding-left:18px;font-size:15px;color:#374151}
.result.err{background:#fdf1f1;border-color:#f3c9c9;color:#9b1c1c}
.content{padding:8px 0 24px}
.content h2{font-size:24px;margin:52px 0 18px}
.content h3{font-size:18px;margin:0 0 6px}
.content p,.content li{color:#4b5563}
.content strong{color:#1f2328}
.content ol,.content ul{padding-left:22px;margin:0 0 14px}
.formula{background:#f4f4f5;border-radius:12px;padding:22px 24px;font-family:ui-monospace,SFMono-Regular,Menlo,Consolas,monospace;font-size:14px;color:#1f2328;overflow-x:auto}
.formula div+div{margin-top:8px}
.formula small{display:block;margin-top:12px;font-family:"DM Sans",sans-serif;font-size:13px;color:#6b7280}
.example{border:1px solid #e5e7eb;border-radius:12px;padding:22px 24px}
.example p:last-child,.example ul:last-child{margin-bottom:0}
.faq details{border:1px solid #e5e7eb;border-radius:10px;padding:16px 20px}
.faq details+details{margin-top:12px}
.faq summary{cursor:pointer;font-weight:600;color:#1f2328;list-style-position:outside}
.faq details p{margin:10px 0 0}
.updated{font-size:13px;color:#6b7280;margin-top:40px}
/* prose pages */
.page-title{padding:44px 0 0}
.page-title h1{font-size:clamp(28px,4vw,34px);margin-bottom:10px}
.meta{font-size:13px;color:#6b7280}
.prose{border:1px solid #e5e7eb;border-radius:14px;padding:36px;margin:28px 0 48px;box-shadow:0 2px 8px rgba(0,0,0,.05)}
.prose h2{font-size:20px;margin:36px 0 14px}
.prose p,.prose li{color:#4b5563;font-size:15.5px}
.prose li{margin-bottom:8px}
@media (max-width:600px){.prose{padding:22px}}
.blue-h{color:#1976d2}
.center{text-align:center}
.commit{background:#f1f7fd;border:1px solid #cfe0f3;border-radius:12px;padding:32px;text-align:center;max-width:680px;margin:28px auto 0}
.who{display:grid;grid-template-columns:repeat(auto-fit,minmax(min(100%,300px),1fr));gap:20px;max-width:880px;margin:0 auto}
.who h3{display:flex;align-items:center;gap:8px;font-size:18px;margin-bottom:8px}
.who .ico{color:#1976d2;width:18px;height:18px}
.form-card{max-width:450px;margin:0 auto 60px;border:1px solid #e5e7eb;border-radius:14px;padding:32px;box-shadow:0 4px 14px rgba(0,0,0,.1)}
.form-card .field{margin-bottom:20px}
/* footer */
.site-footer{border-top:1px solid #eee;margin-top:48px}
.site-footer .top{display:flex;justify-content:space-between;align-items:center;gap:20px;flex-wrap:wrap;padding:28px 0}
.site-footer nav ul{display:flex;gap:6px 22px;flex-wrap:wrap;list-style:none;margin:0;padding:0}
.site-footer nav a{color:#4b5563;font-size:14px}
.site-footer .copy{border-top:1px solid #eee;text-align:center;font-size:14px;color:#6b7280;padding:28px 0}

/* mobile overrides (keep last) */
@media (max-width:640px){.wrap{padding:0 16px}.narrow{padding:0 16px}.hero{padding:44px 0 52px}.hero p{font-size:16.5px}.bigsearch input{font-size:16px}.section{padding:40px 0}.card{padding:18px}.content h2{font-size:21px;margin-top:40px}.formula,.example{padding:18px}.site-footer .top{flex-direction:column;align-items:flex-start}.form-card{padding:22px}}