:root{--ink:#0F1B2A;--slate:#55647A;--muted:#7C8CA1;--canvas:#F4F6F9;--paper:#FFFFFF;--line:#E3E9F0;--line-strong:#CBD5E1;--profit:#0E7C66;--profit-ink:#0A5A4A;--profit-soft:#E7F3EF;--cost:#8296AE;--cost-soft:#EDF1F6;--markup:#B45309;--markup-soft:#FCF2E6;--loss:#B42318;--loss-soft:#FDF0EF;--r-sm:8px;--r-md:12px;--r-lg:16px;--shadow:0 1px 2px rgba(15,27,42,.05),0 12px 28px -18px rgba(15,27,42,.28);--maxw:1120px;--sans:"IBM Plex Sans",system-ui,-apple-system,"Segoe UI",sans-serif;--serif:"Newsreader",Georgia,"Times New Roman",serif;--mono:"IBM Plex Mono",ui-monospace,"SF Mono",Menlo,monospace}*,::after,::before{box-sizing:border-box}html{-webkit-text-size-adjust:100%}body{margin:0;background:var(--canvas);color:var(--ink);font-family:var(--sans);font-size:17px;line-height:1.65;font-variant-numeric:tabular-nums;-webkit-font-smoothing:antialiased}h1,h2,h3{font-family:var(--serif);font-weight:500;letter-spacing:-.012em;line-height:1.18;margin:0}p{margin:0 0 1em}a{color:var(--profit-ink);text-underline-offset:3px}a:hover{color:var(--profit)}:focus-visible{outline:2.5px solid var(--profit);outline-offset:2px;border-radius:3px}.wrap{max-width:var(--maxw);margin:0 auto;padding:0 20px}.eyebrow{font-family:var(--mono);font-size:11.5px;font-weight:500;letter-spacing:.14em;text-transform:uppercase;color:var(--muted);margin:0 0 10px;display:block}.lede{font-size:19px;color:var(--slate);max-width:62ch}.small{font-size:14.5px;color:var(--slate)}.site-head{background:var(--paper);border-bottom:1px solid var(--line)}.head-row{display:flex;align-items:center;gap:16px;justify-content:space-between;padding:14px 20px;max-width:var(--maxw);margin:0 auto;flex-wrap:wrap}.brand{display:flex;flex-direction:column;text-decoration:none;color:inherit;line-height:1.15}.brand b{font-family:var(--serif);font-size:20px;font-weight:600;letter-spacing:-.02em}.brand span{font-size:11.5px;font-family:var(--mono);letter-spacing:.1em;text-transform:uppercase;color:var(--muted)}.head-tools{display:flex;gap:8px;align-items:center;flex-wrap:wrap}.field-inline{display:flex;align-items:center;gap:6px}.field-inline label{font-size:12.5px;color:var(--muted);font-family:var(--mono);letter-spacing:.06em;text-transform:uppercase}select{font-family:var(--sans);font-size:15px;color:var(--ink);background:var(--paper);border:1px solid var(--line-strong);border-radius:var(--r-sm);padding:8px 10px;min-height:40px}.split-rule{height:4px;display:flex}.split-rule i{display:block;height:100%}.split-rule i:first-child{width:60%;background:var(--cost)}.split-rule i:last-child{width:40%;background:var(--profit)}.hero{padding:44px 0 8px}.hero h1{font-size:clamp(2.1rem,5.2vw,3.1rem);margin-bottom:12px}.hero .lede{margin-bottom:0}.calc-shell{background:var(--paper);border:1px solid var(--line);border-radius:var(--r-lg);box-shadow:var(--shadow);margin:26px 0 0;overflow:hidden}.calc-grid{display:grid;grid-template-columns:1fr;gap:0}.calc-inputs{padding:22px}.calc-output{padding:22px;background:#fafbfd;border-top:1px solid var(--line)}@media(min-width:900px){.calc-grid{grid-template-columns:1.05fr .95fr}.calc-output{border-top:0;border-left:1px solid var(--line)}}.modes{border:0;padding:0;margin:0 0 20px}.modes legend{font-family:var(--mono);font-size:11.5px;letter-spacing:.14em;text-transform:uppercase;color:var(--muted);padding:0;margin-bottom:9px}.mode-list{display:flex;flex-wrap:wrap;gap:7px}.mode-list input{position:absolute;opacity:0;width:0;height:0}.mode-list label{display:inline-block;padding:8px 13px;border:1px solid var(--line-strong);border-radius:100px;font-size:14.5px;cursor:pointer;background:var(--paper);color:var(--slate);white-space:nowrap;transition:background .12s,border-color .12s,color .12s}.mode-list label:hover{border-color:var(--cost);color:var(--ink)}.mode-list input:checked+label{background:var(--profit);border-color:var(--profit);color:#fff;font-weight:500}.mode-list input:focus-visible+label{outline:2.5px solid var(--profit);outline-offset:2px}.field{margin-bottom:16px}.field label{display:block;font-size:15px;font-weight:500;margin-bottom:6px}.field .hint{display:block;font-size:13.5px;color:var(--muted);font-weight:400;margin-top:2px}.input-shell{display:flex;align-items:stretch;border:1.5px solid var(--line-strong);border-radius:var(--r-md);background:var(--paper);overflow:hidden;transition:border-color .12s,box-shadow .12s}.input-shell:focus-within{border-color:var(--profit);box-shadow:0 0 0 3px var(--profit-soft)}.input-shell.is-bad{border-color:var(--loss)}.input-shell.is-bad:focus-within{box-shadow:0 0 0 3px var(--loss-soft)}.affix{display:flex;align-items:center;padding:0 13px;background:var(--cost-soft);color:var(--slate);font-family:var(--mono);font-size:15px;border-right:1px solid var(--line);min-width:46px;justify-content:center}.affix.suffix{border-right:0;border-left:1px solid var(--line)}.input-shell input{order:1;flex:1;min-width:0;border:0;outline:0;background:0 0;padding:13px 14px;font-family:var(--mono);font-size:19px;font-weight:500;color:var(--ink);min-height:54px}.affix.is-pct{order:2;border-right:0;border-left:1px solid var(--line)}.msg{display:block;font-size:14px;margin-top:7px;color:var(--loss);font-weight:450}.msg.note{color:var(--markup)}.msg:empty{display:none}.actions{display:flex;flex-wrap:wrap;gap:8px;margin-top:20px}.btn{font-family:var(--sans);font-size:14.5px;font-weight:500;padding:10px 15px;min-height:44px;border-radius:var(--r-sm);border:1px solid var(--line-strong);background:var(--paper);color:var(--slate);cursor:pointer;transition:background .12s,color .12s,border-color .12s}.btn:hover{background:var(--cost-soft);color:var(--ink);border-color:var(--cost)}.res-head{display:flex;align-items:baseline;justify-content:space-between;gap:10px;margin-bottom:14px}.res-head h2{font-size:19px}.badge{font-family:var(--mono);font-size:11px;letter-spacing:.1em;text-transform:uppercase;padding:4px 9px;border-radius:100px;background:var(--profit-soft);color:var(--profit-ink);font-weight:500}.badge.is-loss{background:var(--loss-soft);color:var(--loss)}.badge.is-idle{background:var(--cost-soft);color:var(--muted)}.res-grid{display:grid;grid-template-columns:1fr 1fr;gap:9px}.res{background:var(--paper);border:1px solid var(--line);border-radius:var(--r-md);padding:13px 14px}.res .k{font-family:var(--mono);font-size:11px;letter-spacing:.11em;text-transform:uppercase;color:var(--muted);display:block;margin-bottom:5px}.res .v{font-family:var(--mono);font-size:23px;font-weight:600;letter-spacing:-.02em;line-height:1.15;display:block;word-break:break-word}.res.wide{grid-column:1/-1}.res.is-margin{background:var(--profit-soft);border-color:#cde6de}.res.is-margin .v{color:var(--profit-ink)}.res.is-markup{background:var(--markup-soft);border-color:#f0dfc6}.res.is-markup .v{color:var(--markup)}.res.is-loss{background:var(--loss-soft);border-color:#f3d3d0}.res.is-loss .v{color:var(--loss)}.res .given{font-size:11px;font-family:var(--mono);color:var(--muted);letter-spacing:.06em}.splitbar{margin-top:16px}.splitbar-track{display:flex;height:46px;border-radius:var(--r-sm);overflow:hidden;background:var(--cost-soft);border:1px solid var(--line)}.splitbar-seg{display:flex;align-items:center;justify-content:center;min-width:0;font-family:var(--mono);font-size:12.5px;font-weight:500;color:#fff;white-space:nowrap;overflow:hidden;transition:width .18s}.seg-cost{background:var(--cost)}.seg-profit{background:var(--profit)}.seg-profit.is-loss{background:var(--loss)}.splitbar-key{display:flex;gap:16px;margin-top:9px;font-size:13.5px;color:var(--slate);flex-wrap:wrap}.key{display:flex;align-items:center;gap:6px}.key i{width:11px;height:11px;border-radius:3px;display:inline-block;flex:none}details.maths{margin-top:16px;border-top:1px solid var(--line);padding-top:12px}details.maths summary{cursor:pointer;font-size:14.5px;font-weight:500;color:var(--slate);list-style:none}details.maths summary::-webkit-details-marker{display:none}details.maths summary::before{content:"+ ";font-family:var(--mono);color:var(--profit)}details.maths[open] summary::before{content:"− "}.working{font-family:var(--mono);font-size:14px;line-height:2;color:var(--slate);margin-top:9px;white-space:pre-wrap;word-break:break-word}.adv{border-top:1px solid var(--line);background:#fafbfd}.adv>summary{cursor:pointer;padding:16px 22px;font-weight:500;font-size:15.5px;list-style:none;display:flex;align-items:center;justify-content:space-between;gap:10px}.adv>summary::-webkit-details-marker{display:none}.adv>summary::after{content:"+";font-family:var(--mono);color:var(--profit);font-size:19px}.adv[open]>summary::after{content:"−"}.adv-body{padding:0 22px 22px}.adv-cols{display:grid;grid-template-columns:1fr;gap:0 22px}@media(min-width:760px){.adv-cols{grid-template-columns:1fr 1fr}}.adv-group{margin-bottom:6px}.adv-group h3{font-size:15px;font-family:var(--sans);font-weight:600;margin:14px 0 10px}.adv-field{display:flex;align-items:center;gap:10px;margin-bottom:9px}.adv-field label{flex:1;font-size:14.5px;color:var(--slate)}.adv-field .input-shell{width:150px;flex:none}.adv-field .input-shell input{font-size:15.5px;padding:8px 10px;min-height:42px}.adv-field .affix{min-width:34px;padding:0 8px;font-size:13.5px}.switch{display:flex;align-items:center;gap:9px;margin-bottom:10px;font-size:14.5px;color:var(--slate)}.switch input{width:19px;height:19px;accent-color:var(--profit)}.adv-out{background:var(--paper);border:1px solid var(--line);border-radius:var(--r-md);padding:14px;margin-top:12px}.adv-line{display:flex;justify-content:space-between;gap:12px;padding:7px 0;font-size:14.5px;border-bottom:1px dashed var(--line)}.adv-line:last-child{border-bottom:0}.adv-line b{font-family:var(--mono);font-weight:600}.adv-line.total{border-top:1.5px solid var(--line-strong);border-bottom:0;margin-top:5px;padding-top:11px;font-weight:600}.adv-line.total.contrib b,.adv-line.total.gross b{color:var(--profit-ink)}.adv-line.neg b{color:var(--loss)}.section{padding:52px 0;border-top:1px solid var(--line)}.section h2{font-size:clamp(1.5rem,3.2vw,2.05rem);margin-bottom:12px}.section h3{font-size:1.18rem;margin:26px 0 8px}.section-intro{max-width:66ch}.cols2{display:grid;grid-template-columns:1fr;gap:22px}@media(min-width:820px){.cols2{grid-template-columns:1fr 1fr;gap:34px}}.card{background:var(--paper);border:1px solid var(--line);border-radius:var(--r-md);padding:20px}.card h3{margin-top:0}.formula{font-family:var(--mono);font-size:16px;background:var(--paper);border:1px solid var(--line);border-left:3px solid var(--profit);border-radius:var(--r-sm);padding:14px 16px;margin:12px 0;overflow-x:auto;white-space:nowrap}.formula.markup{border-left-color:var(--markup)}table{width:100%;border-collapse:collapse;font-size:15px;background:var(--paper)}.table-wrap{overflow-x:auto;border:1px solid var(--line);border-radius:var(--r-md);margin:16px 0}td,th{padding:11px 14px;text-align:left;border-bottom:1px solid var(--line);white-space:nowrap}th{font-family:var(--mono);font-size:11.5px;letter-spacing:.09em;text-transform:uppercase;color:var(--muted);font-weight:500;background:#fafbfd}tbody tr:last-child td{border-bottom:0}td.num{font-family:var(--mono);font-variant-numeric:tabular-nums}td.m{color:var(--profit-ink);font-weight:600}td.u{color:var(--markup);font-weight:600}caption{caption-side:bottom;text-align:left;font-size:13.5px;color:var(--muted);padding:10px 14px}.callout{background:var(--markup-soft);border:1px solid #f0dfc6;border-radius:var(--r-md);padding:18px 20px;margin:20px 0}.callout h3{margin-top:0;font-family:var(--sans);font-size:16.5px;font-weight:600}.callout p:last-child{margin-bottom:0}.callout.good{background:var(--profit-soft);border-color:#cde6de}.diagram{background:var(--paper);border:1px solid var(--line);border-radius:var(--r-md);padding:20px 16px;margin:20px 0}.diagram svg{width:100%;height:auto;display:block}.diagram figcaption{font-size:14px;color:var(--slate);margin-top:12px;padding:0 4px}.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}.faq{border:1px solid var(--line);border-radius:var(--r-md);background:var(--paper);overflow:hidden}.faq details{border-bottom:1px solid var(--line)}.faq details:last-child{border-bottom:0}.faq summary{cursor:pointer;padding:16px 20px;font-weight:500;font-size:16.5px;list-style:none;display:flex;justify-content:space-between;gap:14px;align-items:flex-start}.faq summary::-webkit-details-marker{display:none}.faq summary::after{content:"+";font-family:var(--mono);color:var(--profit);font-size:19px;flex:none;line-height:1.4}.faq details[open] summary::after{content:"−"}.faq .a{padding:0 20px 18px;color:var(--slate);font-size:16px}.faq .a p:last-child{margin-bottom:0}.tools{display:grid;grid-template-columns:repeat(auto-fill,minmax(215px,1fr));gap:9px;margin-top:18px}.tool{background:var(--paper);border:1px solid var(--line);border-radius:var(--r-sm);padding:13px 15px;font-size:15px;display:flex;justify-content:space-between;align-items:center;gap:8px}.tool a{font-weight:500;text-decoration:none}.tool a::after{content:" →";color:var(--muted)}.site-foot{background:var(--ink);color:#b6c2d2;padding:44px 0 30px;margin-top:0}.site-foot a{color:#fff}.foot-grid{display:grid;grid-template-columns:1fr;gap:26px}@media(min-width:760px){.foot-grid{grid-template-columns:1.6fr 1fr 1fr}}.foot-grid h3{font-family:var(--sans);font-size:13px;letter-spacing:.1em;text-transform:uppercase;color:#7f8fa6;font-weight:600;margin:0 0 12px}.foot-list{list-style:none;padding:0;margin:0;font-size:15px;line-height:2}.foot-note{border-top:1px solid #24344a;margin-top:28px;padding-top:18px;font-size:13.5px;color:#7f8fa6}.foot-note p{margin-bottom:.6em}@media(max-width:520px){.res-grid{grid-template-columns:1fr}.adv-field{flex-wrap:wrap}.adv-field .input-shell{width:100%}}@media(prefers-reduced-motion:reduce){*{transition:none!important;animation:none!important}}@media print{.actions,.adv,.modes,.section,.site-foot,.site-head{display:none!important}body{background:#fff}.calc-shell{box-shadow:none;border:1px solid #999}}.mono{font-family:var(--mono)}