:root{--ink:#162d35;--muted:#566870;--line:#dce4e7;--green:#a7f369;--blue:#146477;--paper:#f5f8f9}*{box-sizing:border-box}html{scroll-behavior:smooth;scroll-padding-top:100px}body{margin:0;font-family:Inter,ui-sans-serif,-apple-system,BlinkMacSystemFont,"Segoe UI",sans-serif;color:var(--ink);font-size:16px;line-height:1.65}a{color:var(--blue);text-underline-offset:4px}button,input{font:inherit}button,a,input,summary{-webkit-tap-highlight-color:transparent}button{cursor:pointer}a:focus-visible,button:focus-visible,input:focus-visible,summary:focus-visible{outline:3px solid #1974b4;outline-offset:4px}[hidden]{display:none!important}.skip{position:absolute;left:16px;top:-70px;background:white;padding:12px;z-index:100}.skip:focus{top:5px}header{background:#fff;border-bottom:1px solid var(--line)}.header-inner{max-width:1280px;margin:auto;min-height:90px;padding:18px 36px;display:flex;justify-content:space-between;align-items:center;gap:24px}.brand{display:flex;align-items:center;color:var(--ink);font-weight:750;font-size:22px;text-decoration:none;letter-spacing:-.7px}.brand>span:last-child{font-weight:400}.brandmark{display:inline-grid;place-items:center;width:39px;height:39px;background:var(--ink);color:var(--green);border-radius:9px;margin-right:10px;font-size:24px;font-weight:750!important}nav{display:flex;gap:28px}nav a{text-decoration:none;font-size:14px;color:var(--ink);font-weight:600}.hero{max-width:1208px;margin:38px auto 0;padding:52px 64px;background:var(--ink);color:white;border-radius:18px;position:relative;overflow:hidden;border-bottom:6px solid var(--green)}.eyebrow{font-size:12px;letter-spacing:1.7px;font-weight:750;text-transform:uppercase}.hero .eyebrow{color:var(--green)}h1{font-size:42px;letter-spacing:-1.5px;line-height:1.15;margin:16px 0}h2{font-size:27px;letter-spacing:-.65px;line-height:1.25}h3{font-size:19px;line-height:1.4}.hero h1{font-size:52px;max-width:800px;letter-spacing:-2px;margin:21px 0}.hero h1 span{color:var(--green)}.hero p{color:#d6e2e5;max-width:650px;font-size:18px;line-height:1.6}.search-label{font-size:14px;display:block;margin-top:25px;margin-bottom:8px}.search-wrap{max-width:650px;display:flex;align-items:center;background:white;border-radius:8px;color:var(--ink);padding:0 18px;gap:14px}.search-wrap>span{font-size:30px}.search-wrap input{width:100%;border:0;background:none;padding:16px 0;outline-offset:0}.hero-meta{display:flex;gap:26px;font-size:13px;margin-top:17px;color:#d6e2e5}.directory,.principles{max-width:1280px;padding:54px 36px;margin:auto}.section-heading{display:flex;align-items:center;justify-content:space-between;gap:20px}.section-heading h2{margin:9px 0 24px}.section-heading>span{font-size:14px;color:var(--muted)}.filters{display:flex;gap:8px;flex-wrap:wrap;margin-bottom:26px}.filters button{background:white;border:1px solid var(--line);padding:8px 17px;border-radius:24px;font-size:14px;color:var(--muted)}.filters .active{background:var(--ink);color:white;border-color:var(--ink)}.cards{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:18px}.card{border:1px solid var(--line);border-radius:12px;padding:25px;text-decoration:none;color:var(--ink);transition:transform .15s,border-color .15s;background:white}.card:hover{border-color:var(--blue);transform:translateY(-3px)}.category{font-size:12px;font-weight:650;text-transform:uppercase;letter-spacing:.8px;color:var(--blue)}.card h3{display:flex;justify-content:space-between;gap:10px;margin:13px 0 10px}.card h3 span{color:var(--blue);font-size:21px}.card p{font-size:14px;line-height:1.6;color:var(--muted);margin:0}.principles{border-top:1px solid var(--line);padding-bottom:65px}.principle-grid{display:grid;grid-template-columns:repeat(3,1fr);gap:48px;margin:28px 0}.principle-grid span{font-size:14px;color:var(--blue);font-weight:700}.principle-grid p{color:var(--muted);font-size:15px}.principle-grid h3{margin:7px 0}.calc-page{max-width:1320px;padding:24px 36px 70px;margin:auto}.breadcrumb{font-size:13px;color:var(--muted);margin:0 0 25px}.breadcrumb a{text-decoration:none}.calc-heading{margin-left:190px;max-width:900px;margin-bottom:30px}.calc-heading h1{font-size:38px}.calc-heading>p{color:var(--muted);margin:14px 0;max-width:710px}.byline{font-size:12px;color:var(--muted);display:flex;gap:10px;flex-wrap:wrap}.calc-layout{display:grid;grid-template-columns:160px minmax(0,620px) minmax(180px,1fr);gap:30px;align-items:start}.contents{position:sticky;top:24px;font-size:13px;display:flex;flex-direction:column;gap:14px;padding-top:9px}.contents a{text-decoration:none;color:var(--muted)}.contents a:hover{color:var(--blue)}.calculator{border:1px solid #cddcdf;border-top:4px solid var(--blue);border-radius:12px;padding:28px;background:white;box-shadow:0 8px 28px #102d3509}.calc-card-heading{display:flex;align-items:center;justify-content:space-between;gap:10px;border-bottom:1px solid var(--line);padding-bottom:18px;margin-bottom:20px}.calc-card-heading h2{margin:0;font-size:20px}.calc-card-heading>span{font-size:12px;color:var(--muted)}.field{margin-bottom:19px}.field label{display:block;font-size:14px;font-weight:600;margin-bottom:6px}.field input{width:100%;border:1px solid #b7c9ce;padding:10px 13px;border-radius:6px;background:#fbfcfd;color:var(--ink);font-size:18px;min-height:48px}.field input:focus{border-color:var(--blue);background:#fff}.results{border-radius:8px;overflow:hidden;margin-top:25px;background:#f0f7f4}.result{padding:15px 20px;display:flex;justify-content:space-between;align-items:center;gap:15px;border-top:1px solid #d8e6df;font-size:14px}.result strong{font-size:20px;white-space:nowrap;font-variant-numeric:tabular-nums}.result small{font-size:13px;font-weight:500}.result.primary{display:block;background:#e6f6db;border:0;padding:23px}.primary>span{display:block}.primary strong{font-size:38px;line-height:1.3;display:block;margin-top:7px;white-space:normal;overflow-wrap:anywhere}.primary small{font-size:18px}.actions{display:flex;gap:12px;margin-top:20px;flex-wrap:wrap}.actions button{border:1px solid var(--line);border-radius:6px;padding:8px 14px;background:white;color:var(--ink);font-size:14px}.actions button:hover{background:var(--paper)}.error{background:#fff0ef;color:#9e2520;border:1px solid #e5b1ab;padding:12px;border-radius:6px}.under-calculator{text-align:center;font-size:12px;color:var(--muted);padding:14px}.calculator-column article{padding:5px 5px}.calculator-column article h2{margin-top:40px;font-size:25px}.calculator-column article p{color:#43565f}.formula{padding:21px;background:var(--paper);border-left:3px solid var(--blue);font-family:ui-monospace,monospace;font-size:15px;line-height:1.9;border-radius:0 8px 8px 0}details{border-bottom:1px solid var(--line);padding:15px 0}summary{font-weight:600;cursor:pointer;font-size:16px}details p{margin-bottom:4px}.small{font-size:13px;color:var(--muted)}.related{background:var(--paper);border-radius:10px;padding:23px}.related h2{font-size:20px;margin:8px 0 20px}.related>a{display:flex;justify-content:space-between;gap:12px;text-decoration:none;font-size:14px;color:var(--ink);padding:14px 0;border-top:1px solid var(--line)}.tip{border-top:1px solid var(--line);padding-top:20px;margin-top:12px;font-size:14px}.tip p{color:var(--muted);margin-bottom:0}.prose{max-width:810px;margin:0 auto;padding:45px 30px 75px;min-height:60vh}.prose h1{margin-bottom:32px}.prose h2{margin-top:36px}.prose p{color:#43565f}.intro{font-size:20px;color:var(--muted)}footer{background:var(--paper);border-top:1px solid var(--line)}.footer-inner{max-width:1280px;margin:auto;padding:45px 36px;display:grid;grid-template-columns:2fr 1fr 1fr;gap:35px}.footer-inner>div{display:flex;flex-direction:column;align-items:flex-start;gap:8px}.footer-inner p{margin:0 0 14px;color:var(--muted);font-size:14px}.footer-inner strong{font-size:14px;margin-bottom:5px}.footer-inner a:not(.brand),.footer-inner small{font-size:13px;color:var(--muted);text-decoration:none}@media(max-width:1050px){.hero{margin:25px 24px 0;padding:42px}.calc-layout{grid-template-columns:minmax(0,650px) minmax(180px,1fr)}.contents{display:none}.calc-heading{margin-left:0}.cards{grid-template-columns:repeat(2,minmax(0,1fr))}}@media(max-width:700px){.header-inner{padding:17px 20px;min-height:78px;flex-wrap:wrap;gap:12px}.brand{font-size:20px}nav{gap:20px}nav a{font-size:13px}.hero{margin:20px 16px 0;padding:30px 24px;border-radius:12px}.hero h1{font-size:36px;letter-spacing:-1.3px}.hero p{font-size:16px}.hero-meta{gap:13px;flex-wrap:wrap;font-size:12px}.search-wrap input{font-size:14px}.directory,.principles{padding:35px 20px}.cards{grid-template-columns:1fr;gap:12px}.card{padding:21px}.section-heading{align-items:start}.section-heading>span{white-space:nowrap;font-size:12px}.section-heading h2{font-size:24px}.principle-grid{grid-template-columns:1fr;gap:22px}.calc-page{padding:22px 16px 45px}.calc-layout{grid-template-columns:1fr;gap:25px}.calc-heading h1{font-size:32px}.byline{font-size:12px}.calculator{padding:20px}.result{padding:13px;font-size:13px}.result strong{font-size:18px}.primary strong{font-size:34px}.related{margin-top:15px}.footer-inner{grid-template-columns:1fr 1fr;padding:30px 22px;gap:25px}.footer-inner>div:first-child{grid-column:1/-1}.prose{padding:30px 22px 50px}.prose h1{font-size:34px}}@media(prefers-reduced-motion:reduce){html{scroll-behavior:auto}.card{transition:none}}@media print{header,footer,.contents,.related,.actions,.skip{display:none!important}.calc-layout{display:block}.calc-heading{margin:0}.calc-page{padding:0}.calculator{box-shadow:none;break-inside:avoid}.field{display:inline-block;width:46%;margin-right:3%}body{font-size:12px}.calculator-column article h2{margin-top:20px}.results{print-color-adjust:exact}}
/* Unit controls and an accessible conversion reference. */
.input-section{border:1px solid var(--line);border-radius:8px;margin:16px 0;padding:0}.input-section>summary{padding:16px;font-size:16px}.input-summary{display:block;font-size:14px;font-weight:500;margin:5px 0 0 19px;color:var(--muted)}.edit-assumptions{display:block;margin-left:19px;font-size:12px;font-weight:500;color:var(--blue)}.input-section .input-group{margin:0 12px 12px;border:0}.input-section[open] .edit-assumptions{display:none}
.interactive-fields{border:0;margin:0;padding:0;min-width:0}.interactive-fields:disabled .actions{display:none}
.cost-guide-list dt{font-weight:700;margin-top:22px}.cost-guide-list dd{margin:5px 0 0;color:#43565f}
.input-group{border:1px solid var(--line);border-radius:8px;padding:16px;margin:0 0 24px;min-width:0}.input-group legend{font-weight:700;padding:0 8px}.input-group .field:last-child{margin-bottom:0}
.field select{font:inherit;width:100%;min-height:48px;border:1px solid #b7c9ce;border-radius:6px;background:#fbfcfd;color:var(--ink);padding:10px 13px;font-size:16px}
.field select:focus-visible{outline:3px solid #1974b4;outline-offset:4px}.input-help{font-size:14px;color:var(--muted);margin:0 0 22px}.table-scroll{max-width:100%;overflow-x:auto}.conversion-table{width:100%;border-collapse:collapse;font-variant-numeric:tabular-nums;font-size:14px}.conversion-table caption{text-align:left;font-size:13px;color:var(--muted);padding:8px 0}.conversion-table th,.conversion-table td{text-align:right;border-bottom:1px solid var(--line);padding:11px 9px}.conversion-table thead th{background:var(--paper);vertical-align:bottom}.conversion-table tbody th{font-weight:600}.conversion-table tbody tr:nth-child(even){background:#f8fafb}@media print{.table-scroll{overflow:visible}.conversion-table{break-inside:avoid}}
.result strong{white-space:normal;overflow-wrap:anywhere;text-align:right;min-width:0}.result.primary strong{text-align:left}
.calculator-visual{margin-top:24px;border-top:1px solid var(--line);padding-top:16px}.tire-figure{margin:0 0 20px}.tire-figure svg{display:block;width:100%;max-width:440px;margin:auto}.tire-figure figcaption{font-size:13px;color:var(--muted)}.calculator-visual .table-scroll{margin-bottom:20px}.calculator-visual .conversion-table th:first-child{text-align:left}.calculator-visual .conversion-table caption{font-weight:600;color:var(--ink)}
/* Search-led directory and two-column calculator pages. */
.home-intro{max-width:1208px;margin:30px auto 0;padding:36px;border-radius:14px;background:linear-gradient(120deg,#f0f6ec,#eef5f8)}
.home-search-row{display:grid;grid-template-columns:1fr 1.4fr;gap:48px;align-items:center}.home-intro h1{font-size:38px;margin:14px 0 24px}.home-intro h1 span{color:var(--blue)}.home-search .search-label{margin-top:0}.home-search .search-wrap{max-width:none;border:1px solid #cddcdf;border-radius:30px;box-shadow:0 5px 20px #162d3508}.home-search p{font-size:13px;color:var(--muted)}
.category-tiles{display:grid;grid-template-columns:repeat(5,minmax(0,1fr));gap:14px;margin-top:22px;background:#fff;padding:20px;border-radius:12px}.category-tiles a{display:flex;flex-direction:column;align-items:center;justify-content:center;gap:8px;padding:18px 10px;min-height:160px;border:1px solid var(--line);border-radius:8px;text-align:center;text-decoration:none;color:var(--ink);background:#f8fafb}.category-tiles a:hover{border-color:var(--blue);background:#f1f8ed}.category-tiles svg{width:36px;height:36px;fill:none;stroke:var(--blue);stroke-width:1.8;stroke-linejoin:round;stroke-linecap:round}.category-tiles strong{font-size:14px}.category-tiles span{font-size:12px;color:var(--muted)}
@media(min-width:1051px){
.calc-page{display:grid;grid-template-columns:minmax(0,1fr) 430px;grid-template-areas:'crumb crumb' 'heading calculator' 'toc calculator' 'article calculator' 'article related';column-gap:42px;row-gap:24px;align-items:start;max-width:1200px;padding-top:30px}
.calc-page>.breadcrumb{grid-area:crumb;margin:0}.calc-heading{grid-area:heading;margin:0}.calc-heading h1{font-size:32px}.calc-layout,.calculator-column{display:contents}.calculator{grid-area:calculator;padding:24px}.contents{grid-area:toc;position:static;display:flex;gap:8px;font-size:14px;padding:0}.calculator-column>article{grid-area:article;padding:0}.calculator-column>article h2:first-child{margin-top:0}.related{grid-area:related}.under-calculator{display:none}
}
@media(max-width:1050px){.home-intro{margin:24px}.home-search-row{gap:24px}.home-intro h1{font-size:32px}.category-tiles{grid-template-columns:repeat(3,minmax(0,1fr))}}
@media(max-width:700px){.home-intro{margin:16px;padding:24px 16px}.home-search-row{grid-template-columns:1fr;gap:6px}.home-intro h1{font-size:32px}.category-tiles{grid-template-columns:repeat(2,minmax(0,1fr));padding:12px;gap:10px}.category-tiles a{min-height:135px}.home-search .search-wrap{padding:0 12px}.home-search .search-wrap input{min-width:0}}
@media print{.calc-page{display:block}.calculator-column{display:block}.calculator{break-inside:auto}.home-intro{background:white}.category-tiles{display:none}}
.search-hits{background:white;border:1px solid var(--line);border-radius:8px;padding:12px;margin-top:12px}.search-hits p{margin:0 0 6px}.search-hits a{display:block;font-size:14px;padding:9px 4px;text-decoration:none;border-top:1px solid var(--line)}