:root{color-scheme:light;--ink:#102f40;--sub:#47616d;--line:#d9e2e4;--bg:#f5f8f8;--white:#fff;--accent:#f3bf58;--focus:#006c91;font-family:Arial,Helvetica,sans-serif;font-size:16px;line-height:1.55}
*{box-sizing:border-box}html{scroll-behavior:smooth}body{margin:0;color:var(--ink);background:var(--bg)}a{color:inherit}button,input{font:inherit}button{cursor:pointer}.wrap{width:min(1160px,calc(100% - 48px));margin-inline:auto}.skip-link{position:absolute;left:12px;top:-60px;background:#fff;padding:10px;z-index:10}.skip-link:focus{top:12px}:focus-visible{outline:3px solid var(--focus);outline-offset:3px}.sr-only{position:absolute;width:1px;height:1px;padding:0;margin:-1px;overflow:hidden;clip:rect(0,0,0,0);white-space:nowrap;border:0}
.site-header{background:var(--ink);color:#fff}.header-inner{display:flex;align-items:center;justify-content:space-between;gap:24px;min-height:76px}.brand,.footer-brand{text-decoration:none;font-family:'Trebuchet MS',Arial,sans-serif;font-weight:700}.brand{display:inline-flex;align-items:center;gap:12px;font-size:1.2rem;letter-spacing:-.035em}.brand-mark{width:40px;height:40px;display:grid;place-items:center;border:2px solid var(--accent);border-radius:10px;color:var(--accent);font-size:1.1rem;letter-spacing:-.08em}.brand-tick{font-size:.7rem}.brand-domain{color:#b4c5cc}.site-header nav{display:flex;gap:27px;align-items:center}.site-header nav a{text-decoration:none;font-size:.91rem;font-weight:600;color:#d8e5e8}.site-header nav a:hover,.site-header nav a:focus-visible{color:#fff}.site-header .language-link{border:1px solid #66818d;padding:7px 12px;border-radius:6px}
main{padding-bottom:80px}.intro{padding:54px 0 32px}.eyebrow{font-size:.75rem;font-weight:700;letter-spacing:.15em;color:#236b7a;margin:0 0 12px}h1,h2,h3,p{margin-top:0}h1,h2,h3{font-family:'Trebuchet MS',Arial,sans-serif;letter-spacing:-.045em;line-height:1.15}h1{font-size:clamp(2.4rem,5vw,4.1rem);margin-bottom:13px}h2{font-size:clamp(1.5rem,2.3vw,2.1rem)}.intro>p:last-child{color:var(--sub);font-size:1.05rem;max-width:650px;margin-bottom:0}
.calculator-grid{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:18px}.calc-card{background:#fff;border:1px solid var(--line);border-radius:14px;padding:28px;box-shadow:0 10px 28px rgba(16,47,64,.045)}.card-heading{display:flex;align-items:flex-start;gap:13px;min-height:83px}.card-heading h2{font-size:1.35rem;margin:2px 0 4px}.card-heading p{color:var(--sub);font-size:.92rem}.step{display:grid;place-items:center;flex:none;width:32px;height:32px;background:#e4f0f0;color:#236b7a;border-radius:7px;font-family:'Trebuchet MS',Arial,sans-serif;font-size:.78rem;font-weight:700}.input-row{display:flex;align-items:end;gap:14px}.input-row .field{flex:1;min-width:0}.input-row.single{max-width:280px}.field label{display:block;font-size:.9rem;font-weight:700;margin-bottom:7px}.field input{width:100%;height:58px;border:1.5px solid #aac0c7;border-radius:8px;padding:10px 15px;color:var(--ink);background:#fff;font-family:'Trebuchet MS',Arial,sans-serif;font-size:1.5rem;font-weight:600}.field input:focus{border-color:var(--focus);outline:3px solid #c5e9f3}.field input[aria-invalid=true]{border-color:#b43c34}.field-divider{font-size:1.8rem;line-height:58px;color:#8da4ae}.input-hint,.field-error{font-size:.83rem;margin:8px 0 0;min-height:21px}.input-hint{color:var(--sub)}.field-error{color:#a02e2a}.result{display:flex;align-items:center;justify-content:space-between;gap:16px;background:var(--ink);color:#fff;border-radius:10px;margin-top:23px;padding:19px 20px;min-height:100px}.result-label{display:block;color:#bed1d8;font-weight:700;letter-spacing:.1em;font-size:.68rem}.result output{font-family:'Trebuchet MS',Arial,sans-serif;font-size:clamp(1.85rem,3vw,2.55rem);font-weight:700;line-height:1.2;overflow-wrap:anywhere}.result-unit{margin-left:8px;color:#d4e3e8}.copy-button{background:var(--accent);color:#122c35;border:0;border-radius:6px;padding:10px 12px;white-space:nowrap;font-size:.82rem;font-weight:700}.copy-button:hover{background:#ffcf74}.copy-button:disabled{opacity:.5;cursor:not-allowed}.card-note{color:var(--sub);font-size:.81rem;margin:12px 0 0;min-height:20px}
.quick-values{display:grid;grid-template-columns:repeat(4,1fr);gap:0;background:#e8f1f1;border:1px solid #d3e3e4;border-radius:10px;margin:20px 0 82px;padding:16px 0}.quick-values>div{display:flex;flex-direction:column;align-items:center;padding:4px 10px;border-right:1px solid #cbdfe0}.quick-values>div:last-child{border:0}.quick-values span{color:var(--sub);font-size:.87rem}.quick-values strong{font-family:'Trebuchet MS',Arial,sans-serif;font-size:1.25rem}
.content-section{margin-bottom:82px}.section-heading{display:flex;justify-content:space-between;gap:24px;align-items:end;margin-bottom:22px}.section-heading h2,.explainer h2{margin-bottom:8px}.section-heading p:last-child{color:var(--sub);margin:0}.download-links{display:flex;gap:20px;flex-wrap:wrap}.text-link{flex:none;color:#145d76;font-weight:700;text-underline-offset:4px}.chart-grid{display:grid;grid-template-columns:repeat(4,minmax(0,1fr));gap:15px}table{border-collapse:collapse;width:100%;background:white;border:1px solid var(--line);border-radius:9px;overflow:hidden;font-variant-numeric:tabular-nums}caption{font-family:'Trebuchet MS',Arial,sans-serif;font-weight:700;text-align:left;padding:14px 16px;background:#e6eff0}th,td{text-align:left;padding:6px 16px;border-bottom:1px solid #e9eff0}thead th{font-size:.73rem;color:var(--sub);text-transform:uppercase;letter-spacing:.04em;padding-top:12px;padding-bottom:10px}tbody th{font-weight:500}tbody td{font-weight:700}tbody tr:last-child th,tbody tr:last-child td{border-bottom:0}tbody tr:nth-child(even){background:#f8fafa}.chart-note,.muted{color:var(--sub);font-size:.91rem}.chart-note{margin:17px 0 0}.explainer{border-top:1px solid var(--line);padding-top:47px}.explain-grid{display:grid;grid-template-columns:1fr 1fr;gap:42px;margin-top:25px}.explain-grid p{color:var(--sub)}.explain-grid strong{color:var(--ink)}.formula{background:white;border-left:4px solid var(--accent);border-radius:0 6px 6px 0;font-family:'Trebuchet MS',Arial,sans-serif;font-weight:600;padding:14px 18px;margin:18px 0}.explainer .muted{margin-top:10px}.excel-callout{background:#dcebef;border-radius:14px;padding:30px 36px;display:flex;align-items:center;justify-content:space-between;gap:30px}.excel-callout h2{margin-bottom:8px}.excel-callout p:last-child{max-width:710px;color:var(--sub);margin:0}.primary-link{background:var(--ink);color:#fff;text-decoration:none;border-radius:7px;padding:12px 17px;font-weight:700;white-space:nowrap}.primary-link:hover{background:#23546a}
.site-footer{background:var(--ink);color:#fff;padding:38px 0}.footer-inner{display:flex;justify-content:space-between;gap:24px}.footer-brand{font-size:1.15rem}.site-footer p{color:#b9cbd1;font-size:.87rem;margin:5px 0 0}.site-footer nav{display:flex;flex-wrap:wrap;gap:12px 20px;align-content:center}.site-footer nav a{color:#d4e2e6;font-size:.88rem;text-underline-offset:3px}
.article{max-width:830px;padding-top:55px}.article h1{font-size:clamp(2.3rem,4.5vw,3.6rem)}.article .lede{font-size:1.12rem;color:var(--sub)}.article h2{margin-top:46px}.article p,.article li{line-height:1.75}.article code{font-size:1rem}.article .formula{overflow-x:auto}.example-table{width:100%;margin:20px 0}.example-table td,.example-table th{border:1px solid var(--line);padding:10px}.article .back-link{display:inline-block;margin:25px 0 10px;font-weight:700;color:#145d76}
@media(max-width:850px){.calculator-grid,.explain-grid{grid-template-columns:1fr}.chart-grid{grid-template-columns:repeat(2,minmax(0,1fr))}.quick-values{margin-bottom:65px}.site-header nav{gap:14px}.excel-callout{align-items:flex-start;flex-direction:column}}
@media(max-width:600px){.wrap{width:min(100% - 32px,1160px)}.header-inner{min-height:68px;flex-wrap:wrap;padding:12px 0}.brand{font-size:1.07rem}.site-header nav{width:100%;justify-content:space-between;gap:8px}.site-header nav a{font-size:.79rem}.site-header .language-link{padding:5px 7px}.intro{padding:36px 0 24px}.calc-card{padding:19px}.card-heading{min-height:92px}.card-heading h2{font-size:1.25rem}.field input{font-size:1.35rem}.result{padding:16px;min-height:92px}.result output{font-size:1.85rem}.result-unit{font-size:.83rem}.copy-button{padding:9px;font-size:.73rem}.quick-values{grid-template-columns:repeat(2,1fr);row-gap:12px}.quick-values>div:nth-child(2){border-right:0}.chart-grid{gap:10px}.chart-grid th,.chart-grid td{padding:6px 9px}.chart-grid caption{padding:12px 9px}.section-heading{align-items:start;flex-direction:column}.content-section{margin-bottom:60px}.excel-callout{padding:25px}.footer-inner{flex-direction:column}.article{padding-top:36px}}

/* Keep both calculator results aligned despite the extra input hint on the right. */
.calc-card{display:flex;flex-direction:column}
.calc-card .field-error{margin-bottom:23px}
.calc-card .result{margin-top:auto}

/* Share row heights so the two explanation formulas start at the same level. */
@media(min-width:851px){
  .explain-grid{grid-template-rows:repeat(3,auto)}
  .explain-grid>div{display:grid;grid-row:span 3;grid-template-rows:subgrid}
}

/* Legal pages use the same visual system as the calculator. */
.legal-page{padding-bottom:90px}.legal-page h2{font-size:1.55rem;margin:36px 0 14px}
.legal-page p{max-width:75ch}.legal-page a{color:#145d76;text-underline-offset:3px}
.legal-contact-image{display:block;max-width:100%;height:auto;background:#fff;border:1px solid var(--line);border-radius:9px;padding:5px}