:root{
  --paper:#F4F5F2; --card:#FFFFFF; --ink:#182022; --mute:#58615F; --rule:#D3D8D2;
  --green:#1F4D3A; --green-deep:#153627; --tape:#F6C90E; --tape-ink:#2A2300; --focus:#1F4D3A;
  --radius:6px; --maxw:1080px; --font:"Archivo",system-ui,-apple-system,"Segoe UI",sans-serif;
}
*{box-sizing:border-box}
html{font-family:var(--font);color:var(--ink);background:var(--paper);-webkit-text-size-adjust:100%}
body{margin:0;line-height:1.55;font-size:17px}
.wrap{max-width:var(--maxw);margin:0 auto;padding:0 20px}
a{color:var(--green);text-decoration-thickness:1px;text-underline-offset:3px}
a:hover{color:var(--green-deep)}
:focus-visible{outline:3px solid var(--focus);outline-offset:2px}
.skip{position:absolute;left:-999px;top:8px;background:var(--tape);color:var(--tape-ink);padding:8px 12px;z-index:10}
.skip:focus{left:8px}
h1,h2,h3{line-height:1.15;letter-spacing:-0.01em;font-weight:800;margin:0 0 .5em}
h1{font-size:clamp(1.9rem,4.2vw,2.8rem);max-width:22ch}
h2{font-size:1.45rem;margin-top:2.2rem}
h3{font-size:1.1rem}
p{margin:0 0 1em}
.prose{max-width:70ch}
.prose ul,.prose ol{padding-left:1.3em}
.prose li{margin-bottom:.35em}
.prose table{border-collapse:collapse;margin:0 0 1.2em;font-size:.95rem}
.prose th,.prose td{text-align:left;padding:.45em .7em;border-bottom:1px solid var(--rule);vertical-align:top}
.prose th{font-weight:600}
code{font-family:inherit;font-weight:600;background:#E9ECE7;padding:.05em .35em;border-radius:3px}

/* header with a measuring-tape rule */
.site-head{background:var(--card);border-bottom:1px solid var(--rule)}
.site-head .wrap{display:flex;align-items:center;justify-content:space-between;gap:16px;min-height:64px;flex-wrap:wrap;padding-top:8px;padding-bottom:8px}
.brand{font-weight:800;font-size:1.2rem;text-decoration:none;color:var(--ink);letter-spacing:-0.01em}
.site-nav{display:flex;gap:18px;flex-wrap:wrap}
.site-nav a{text-decoration:none;color:var(--mute);font-weight:600;font-size:.95rem}
.site-nav a:hover{color:var(--ink)}
.tape{height:10px;background:
  repeating-linear-gradient(90deg,transparent 0 31px,var(--tape-ink) 31px 32px) 0 0/32px 10px,
  repeating-linear-gradient(90deg,transparent 0 7px,var(--tape-ink) 7px 8px) 0 5px/8px 5px no-repeat,
  var(--tape)}

/* hero + category cards */
.hero{padding:44px 0 8px}
.hero p{max-width:60ch;font-size:1.1rem;color:var(--mute)}
.group{margin-top:28px}
.group>p{color:var(--mute);margin-top:-.3em}
.cards{list-style:none;padding:0;margin:0;display:grid;grid-template-columns:repeat(auto-fill,minmax(230px,1fr));gap:12px}
.cards a{display:block;background:var(--card);border:1px solid var(--rule);border-left:5px solid var(--green);border-radius:var(--radius);padding:14px 16px;text-decoration:none;color:var(--ink);height:100%}
.cards a:hover{border-left-color:var(--tape)}
.cards strong{display:block;font-weight:800;margin-bottom:4px}
.cards span{color:var(--mute);font-size:.92rem}
.about-strip{margin-top:48px;padding-top:24px;border-top:1px solid var(--rule)}

/* calculator */
.crumbs{font-size:.9rem;color:var(--mute);margin:20px 0 10px}
.crumbs span{margin:0 4px}
.intro{color:var(--mute);font-size:1.05rem}
.calc{display:grid;grid-template-columns:minmax(0,1fr) minmax(280px,.9fr);gap:20px;align-items:start;margin:22px 0 10px}
.calc-form{background:var(--card);border:1px solid var(--rule);border-radius:var(--radius);padding:18px 18px 8px;display:grid;grid-template-columns:1fr 1fr;gap:12px 16px}
.field{display:flex;flex-direction:column;gap:4px}
.field[hidden]{display:none}
.field label{font-weight:600;font-size:.95rem}
.field .help{color:var(--mute);font-size:.82rem;line-height:1.35}
.num{display:flex;align-items:stretch}
input[type=number],select{font:inherit;font-size:1.05rem;padding:9px 10px;border:1px solid #AEB5B0;border-radius:var(--radius);background:#fff;color:var(--ink);width:100%;min-width:0}
.num input{border-radius:var(--radius) 0 0 var(--radius)}
.num .unit{display:flex;align-items:center;padding:0 10px;border:1px solid #AEB5B0;border-left:0;border-radius:0 var(--radius) var(--radius) 0;background:#EEF0EC;color:var(--mute);font-size:.9rem;white-space:nowrap}
.form-note{grid-column:1/-1;color:var(--mute);font-size:.82rem;margin:4px 0 8px}
.calc-result{background:var(--green);color:#fff;border-radius:var(--radius);padding:20px 22px;position:sticky;top:12px}
.result-big{border-bottom:1px solid rgba(255,255,255,.25);padding-bottom:14px;margin-bottom:12px}
.result-big .label{font-size:.95rem;opacity:.9}
.result-big .value{font-size:clamp(2.4rem,6vw,3.4rem);font-weight:800;line-height:1;color:var(--tape);font-variant-numeric:tabular-nums;letter-spacing:-0.02em}
.result-big .value small{font-size:1.1rem;color:#fff;font-weight:600;margin-left:6px;letter-spacing:0}
.result-rows{display:grid;grid-template-columns:1fr auto;gap:6px 14px;margin:0;font-variant-numeric:tabular-nums}
.result-rows dt{opacity:.9}
.result-rows dd{margin:0;font-weight:600;text-align:right;white-space:nowrap}
.result-note{font-size:.88rem;opacity:.85;margin:12px 0 0}
.result-empty{opacity:.9}
.copy{margin-top:14px;font:inherit;font-weight:600;font-size:.9rem;background:var(--tape);color:var(--tape-ink);border:0;border-radius:var(--radius);padding:9px 14px;cursor:pointer}
.copy:hover{background:#FFD83A}

.ad{margin:22px 0;min-height:90px}
.faq details{border-top:1px solid var(--rule);padding:4px 0}
.faq details:last-child{border-bottom:1px solid var(--rule)}
.faq summary{cursor:pointer;font-weight:600;padding:10px 0;list-style:none;display:flex;justify-content:space-between;gap:12px}
.faq summary::-webkit-details-marker{display:none}
.faq summary::after{content:"+";color:var(--green);font-weight:800;flex:none}
.faq details[open] summary::after{content:"–"}
.faq .prose{padding:0 0 12px}
.related ul{list-style:none;padding:0;margin:0;display:grid;grid-template-columns:repeat(auto-fill,minmax(230px,1fr));gap:10px}
.related li{background:var(--card);border:1px solid var(--rule);border-radius:var(--radius);padding:12px 14px}
.related li a{font-weight:600;display:block}
.related li span{color:var(--mute);font-size:.9rem}
.page{padding:28px 0 20px}

.site-foot{margin-top:56px;border-top:1px solid var(--rule);background:var(--card);padding:26px 0 30px;color:var(--mute);font-size:.92rem}
.site-foot nav a{margin-right:16px;font-weight:600}
.fine{margin-top:14px;font-size:.85rem}

@media (max-width:760px){
  body{font-size:16px}
  .calc{grid-template-columns:1fr}
  .calc-form{grid-template-columns:1fr}
  .calc-result{position:static}
  .site-head .wrap{padding-top:10px}
}
@media (prefers-reduced-motion:no-preference){
  .copy{transition:background .15s}
}