/* kVA to Amps — "Busbar" design system */
@font-face{font-family:'Archivo';src:url('/assets/fonts/archivo.woff2') format('woff2');font-weight:400 900;font-display:swap}
@font-face{font-family:'Inter';src:url('/assets/fonts/inter.woff2') format('woff2');font-weight:400 700;font-display:swap}
@font-face{font-family:'JetBrains Mono';src:url('/assets/fonts/jetbrains-mono.woff2') format('woff2');font-weight:400 800;font-display:swap}

:root{
  --bg:#F5F4F0; --ink:#1C1B17; --copper:#B05C1E; --copper-dark:#96500F;
  --panel:#23252B; --panel2:#2E3038; --fieldbg:#17181D; --fieldline:#41444E;
  --lcd:#FFB224; --line:#E3E0D8; --muted:#5C594F; --card:#FFFFFF; --pfbg:#F8EBDD;
  --consoletxt:#EDEBE4; --consolemut:#9B9EA8;
}
*{margin:0;padding:0;box-sizing:border-box}
html{scroll-behavior:smooth}
body{background:var(--bg);color:var(--ink);font-family:'Inter',system-ui,sans-serif;font-size:17px;line-height:1.7;-webkit-font-smoothing:antialiased}
h1,h2,h3{font-family:'Archivo',sans-serif;letter-spacing:-0.015em;line-height:1.22}
.mono{font-family:'JetBrains Mono',monospace}
a{color:var(--copper);text-decoration:none}
a:hover{text-decoration:underline}
.wrap{max-width:1120px;margin:0 auto;padding:0 24px}
p+p{margin-top:12px}
main p{max-width:76ch}

/* ---------- header ---------- */
header.site{position:sticky;top:0;z-index:60;background:rgba(245,244,240,.97);border-bottom:1px solid var(--line)}
.bar{display:flex;align-items:center;gap:26px;min-height:68px}
.logo{display:flex;align-items:center;gap:11px;color:var(--ink)}
.logo:hover{text-decoration:none}
.tile{width:38px;height:38px;border-radius:10px;background:var(--copper);display:flex;align-items:center;justify-content:center;flex:none}
.tile svg{width:21px;height:21px}
.wordmark{font-family:'Archivo',sans-serif;font-weight:800;font-size:20px;letter-spacing:-0.02em}
.wordmark span{color:var(--copper)}
nav.mainnav{margin-left:auto;display:flex;align-items:center;gap:4px}
nav.mainnav>a{color:var(--ink);font-size:15.5px;font-weight:500;padding:9px 13px;border-radius:999px;white-space:nowrap}
nav.mainnav>a:hover{text-decoration:none;background:#ECEAE3}
nav.mainnav>a.pill{background:var(--copper);color:#fff;font-weight:600}
.dropwrap{position:relative}
.dropbtn{display:flex;align-items:center;gap:5px;font:inherit;font-size:15.5px;font-weight:500;color:var(--ink);background:none;border:0;padding:9px 13px;border-radius:999px;cursor:pointer;min-height:44px}
.dropbtn:hover{background:#ECEAE3}
.dropbtn.on{background:var(--copper);color:#fff;font-weight:600}
.dropbtn.on svg path{stroke:#fff}
.dropdown{display:none;position:absolute;top:calc(100% + 8px);left:50%;transform:translateX(-50%);background:var(--panel);border-radius:14px;padding:10px;min-width:290px;box-shadow:0 18px 44px rgba(28,27,23,.28);z-index:70}
.dropdown.open{display:block}
.dropdown a{display:block;color:#E7E4DA;font-size:15.5px;font-weight:500;padding:11px 14px;border-radius:9px;white-space:nowrap}
.dropdown a:hover{background:#2E3038;text-decoration:none;color:#fff}
.dropdown a.cur{color:var(--lcd);font-weight:600}
.burger{display:none;margin-left:auto;width:48px;height:48px;border:1px solid var(--line);border-radius:10px;background:#fff;cursor:pointer;align-items:center;justify-content:center;flex:none}
.burger svg{width:24px;height:24px}
.mmenu{display:none;border-top:1px solid var(--line);padding:8px 0 14px}
.mmenu.open{display:block}
.mmenu a{display:block;color:var(--ink);font-weight:500;padding:12px 6px;min-height:44px;border-bottom:1px solid var(--line)}
.mmenu a:last-child{border-bottom:0}
.mmenu a.pill{color:var(--copper);font-weight:600}
.mmenu .subbtn{display:flex;align-items:center;justify-content:space-between;width:100%;font:inherit;font-weight:500;color:var(--ink);background:none;border:0;border-bottom:1px solid var(--line);padding:12px 6px;min-height:44px;cursor:pointer}
.mmenu .sublist{display:none;padding:2px 0 4px 14px}
.mmenu .sublist.open{display:block}
.mmenu .sublist a{border-bottom:0;padding:10px 6px;font-size:16px}

/* ---------- hero ---------- */
.hero{text-align:center;padding:52px 0 24px}
.hero.left{text-align:left;padding:44px 0 8px}
.kicker{font-family:'JetBrains Mono',monospace;font-size:13px;font-weight:700;letter-spacing:.14em;text-transform:uppercase;color:var(--copper);margin-bottom:14px}
.hero h1{font-size:50px;font-weight:800}
.hero.left h1{font-size:42px}
.hero p.sub{max-width:660px;margin:16px auto 0;color:var(--muted);font-size:18.5px}
.hero.left p.sub{margin-left:0}
.trust{display:flex;justify-content:center;gap:10px;flex-wrap:wrap;margin-top:22px}
.hero.left .trust{justify-content:flex-start}
.trust span{display:inline-flex;align-items:center;gap:7px;background:#fff;border:1px solid var(--line);border-radius:999px;padding:7px 15px;font-size:14px;font-weight:500}
.trust i{width:7px;height:7px;border-radius:50%;background:var(--copper);flex:none}
.crumbs{font-size:14.5px;color:var(--muted);padding-top:22px}
.crumbs a{font-weight:500}

/* ---------- tool console ---------- */
.console{background:var(--panel);border-radius:20px;padding:34px 38px 30px;color:var(--consoletxt);box-shadow:0 18px 44px rgba(28,27,23,.20);margin:14px auto 0;max-width:920px}
.console-head{display:flex;align-items:center;justify-content:space-between;gap:14px;flex-wrap:wrap;margin-bottom:24px}
.console-title{font-family:'Archivo',sans-serif;font-weight:700;font-size:19px;color:#fff;display:flex;align-items:center;gap:10px}
.console-title .tile{width:30px;height:30px;border-radius:8px}
.console-title .tile svg{width:16px;height:16px}
.swap{display:inline-flex;align-items:center;gap:8px;background:var(--panel2);border:1px solid var(--fieldline);color:var(--consoletxt);font:inherit;font-size:14.5px;font-weight:600;border-radius:999px;padding:10px 18px;min-height:44px;cursor:pointer}
.swap b{color:var(--lcd);font-weight:700}
.swap .dim{color:var(--consolemut);font-weight:500}
.cgrid{display:grid;grid-template-columns:minmax(0,1fr) minmax(0,1.35fr) minmax(0,1fr);gap:22px}
.cgrid.c2{grid-template-columns:minmax(0,1fr) minmax(0,1fr)}
.cgrid>*{min-width:0}
label.flabel{display:block;font-size:13px;font-weight:600;letter-spacing:.09em;text-transform:uppercase;color:var(--consolemut);margin-bottom:9px}
.field{display:flex;align-items:stretch;background:var(--fieldbg);border:1px solid var(--fieldline);border-radius:12px;overflow:hidden}
.field input{flex:1;min-width:0;background:none;border:0;color:#fff;font-family:'JetBrains Mono',monospace;font-size:22px;font-weight:700;padding:13px 15px;outline:none}
.field input:focus{box-shadow:inset 0 0 0 2px var(--copper)}
.field .unit{display:flex;align-items:center;padding:0 15px;background:var(--panel2);color:var(--lcd);font-family:'JetBrains Mono',monospace;font-weight:700;font-size:15px}
.field .unitbtn{cursor:pointer;border:0;font:inherit}
.unitseg{display:flex;background:var(--panel2)}
.unitseg button{background:none;border:0;color:#C9CBD2;font-family:'JetBrains Mono',monospace;font-weight:700;font-size:14px;padding:0 13px;cursor:pointer;min-height:44px}
.unitseg button.on{color:var(--lcd);background:#17181D}
.chips{display:flex;gap:7px;flex-wrap:wrap}
.chip{font-family:'JetBrains Mono',monospace;font-size:15px;font-weight:500;background:var(--fieldbg);border:1px solid var(--fieldline);color:#C9CBD2;border-radius:9px;padding:10px 4px;min-height:48px;flex:1;cursor:pointer;text-align:center}
.chip.on{background:var(--copper);border-color:var(--copper);color:#fff;font-weight:700}
.sizechips{display:flex;gap:7px;flex-wrap:wrap;margin-bottom:14px}
.sizechips .chip{flex:0 1 auto;padding:10px 13px}
.customrow{margin-top:9px}
.customrow .field input{font-size:16px;padding:10px 13px}
.customrow .field .unit{font-size:13px}
.seg{display:flex;background:var(--fieldbg);border:1px solid var(--fieldline);border-radius:12px;padding:4px;gap:4px}
.seg button{flex:1;font:inherit;font-weight:600;font-size:15px;color:#C9CBD2;background:none;border:0;border-radius:8px;padding:11px 4px;min-height:44px;cursor:pointer}
.seg button.on{background:var(--copper);color:#fff}
.readout{margin-top:28px;background:var(--fieldbg);border:1px solid var(--fieldline);border-radius:14px;padding:22px 24px 18px;text-align:center}
.readout .rlabel{font-size:12.5px;font-weight:600;letter-spacing:.12em;text-transform:uppercase;color:var(--consolemut)}
.lcd{font-family:'JetBrains Mono',monospace;font-weight:700;font-size:62px;line-height:1.12;color:var(--lcd);margin:4px 0 2px}
.lcd small{font-size:29px}
.lcd.msg{font-size:21px;line-height:1.45;color:#C9CBD2;font-family:'Inter',sans-serif;font-weight:500;padding:14px 0}
.formula-line{font-family:'JetBrains Mono',monospace;font-size:15.5px;color:#C9CBD2;margin-top:6px}
.formula-line b{color:#fff;font-weight:700}
.readouts2{display:grid;grid-template-columns:1fr 1fr;gap:14px;margin-top:28px}
.readouts2 .readout{margin-top:0}
.readouts2 .lcd{font-size:44px}
.copyrow{display:flex;justify-content:center;margin-top:20px}
.copybtn{display:inline-flex;align-items:center;gap:9px;background:var(--copper);color:#fff;font:inherit;font-weight:600;font-size:16px;border:0;border-radius:11px;padding:13px 26px;min-height:50px;cursor:pointer}
.copybtn:hover{background:var(--copper-dark)}
.copybtn.copied{background:#2F7D3B}
.consolenote{text-align:center;color:var(--consolemut);font-size:14px;margin-top:16px}
.consolenote a{color:var(--lcd)}

/* ---------- quick answers ---------- */
.qa{max-width:920px;margin:26px auto 0}
.qa-grid{display:grid;grid-template-columns:1fr 1fr;gap:12px}
.qa-card{background:var(--card);border:1px solid var(--line);border-radius:13px;padding:15px 19px;display:flex;align-items:center;justify-content:space-between;gap:14px}
.qa-card .q{font-size:15.5px;font-weight:500}
.qa-card .a{font-family:'JetBrains Mono',monospace;font-weight:700;font-size:19px;color:var(--copper);white-space:nowrap}

/* ---------- sections ---------- */
section{padding:44px 0 6px}
.sec-head{max-width:760px}
h2{font-size:31px;font-weight:800;margin-bottom:10px}
.sec-head p{color:var(--muted)}
h3.sub{font-size:21px;font-weight:700;margin:26px 0 8px}
.toc{background:#fff;border:1px solid var(--line);border-radius:14px;padding:20px 24px;max-width:920px}
.toc .toch{font-size:15px;letter-spacing:.08em;text-transform:uppercase;color:var(--muted);margin-bottom:10px;font-weight:600}
.toc ul{list-style:none;display:flex;flex-wrap:wrap;gap:8px 26px}
.toc li a{font-weight:500;font-size:16px}
.cards3{display:grid;grid-template-columns:repeat(3,1fr);gap:16px;margin-top:22px}
.cards2{display:grid;grid-template-columns:repeat(2,1fr);gap:16px;margin-top:22px}
.fcard{background:var(--card);border:1px solid var(--line);border-radius:15px;padding:24px}
.fcard .ftag{font-family:'JetBrains Mono',monospace;font-size:12.5px;font-weight:700;letter-spacing:.1em;text-transform:uppercase;color:var(--copper)}
.fcard .fx{font-family:'JetBrains Mono',monospace;font-size:20px;font-weight:700;margin:12px 0 10px;line-height:1.45}
.fcard p{font-size:15.5px;color:var(--muted)}
.pfband{background:var(--pfbg);border:1px solid #EAD3B8;border-left:6px solid var(--copper);border-radius:14px;padding:26px 30px;margin-top:22px}
.pfband h3{font-size:22px;margin-bottom:8px}
.pfband p{max-width:84ch}
.notebox{background:#fff;border:1px solid var(--line);border-left:6px solid var(--panel);border-radius:14px;padding:22px 26px;margin-top:22px}
.notebox h3{font-size:20px;margin-bottom:6px}

/* ---------- tables ---------- */
.tablewrap{background:#fff;border:1px solid var(--line);border-radius:15px;overflow:hidden;margin-top:22px}
.tablescroll{overflow-x:auto}
table{width:100%;border-collapse:collapse;font-size:16px}
th{font-family:'Archivo',sans-serif;font-size:14.5px;text-align:right;background:#EFEDE6;padding:13px 18px;border-bottom:1px solid var(--line);white-space:nowrap}
th:first-child{text-align:left}
td{padding:11px 18px;border-bottom:1px solid var(--line);text-align:right;font-family:'JetBrains Mono',monospace;font-size:15.5px;white-space:nowrap}
td:first-child{text-align:left;font-weight:700}
tr:last-child td{border-bottom:0}
tr.hl td{background:var(--pfbg)}
.chart-actions{display:flex;align-items:center;gap:18px;flex-wrap:wrap;margin-top:16px}
.chart-actions.top{margin:22px 0 4px}
.printbtn{display:inline-flex;align-items:center;gap:9px;background:var(--ink);color:#fff;font:inherit;font-weight:600;font-size:15.5px;border:0;border-radius:10px;padding:12px 22px;min-height:48px;cursor:pointer}
.fulllink{font-weight:600}

/* ---------- calculators grid ---------- */
.calcgrid{display:grid;grid-template-columns:repeat(3,1fr);gap:16px;margin-top:22px}
.ccard{background:var(--card);border:1px solid var(--line);border-radius:15px;padding:22px;display:block;color:var(--ink)}
.ccard:hover{text-decoration:none;border-color:var(--copper)}
.ccard .cic{width:40px;height:40px;border-radius:10px;background:var(--pfbg);display:flex;align-items:center;justify-content:center;margin-bottom:13px}
.ccard .cic svg{width:21px;height:21px}
.ccard h3{font-size:18.5px;margin-bottom:5px}
.ccard p{font-size:15px;color:var(--muted)}
.ccard .go{color:var(--copper);font-weight:600;font-size:15px;display:inline-block;margin-top:10px}

/* ---------- worked example ---------- */
.example{background:var(--panel);color:var(--consoletxt);border-radius:15px;padding:26px 30px;margin-top:22px}
.example .etag{font-family:'JetBrains Mono',monospace;font-size:12.5px;font-weight:700;letter-spacing:.1em;text-transform:uppercase;color:var(--lcd)}
.example p{margin-top:10px;font-size:17px;max-width:88ch}
.example .mono{color:#fff;font-weight:700}
.example .ans{color:var(--lcd);font-weight:700}
.example + .example{margin-top:14px}

/* ---------- FAQ ---------- */
.faq{margin-top:20px;border:1px solid var(--line);border-radius:15px;overflow:hidden;background:#fff}
.faq details{border-bottom:1px solid var(--line)}
.faq details:last-child{border-bottom:0}
.faq summary{display:flex;align-items:center;justify-content:space-between;gap:16px;padding:19px 24px;min-height:44px;font-weight:600;font-size:17px;cursor:pointer;list-style:none}
.faq summary::-webkit-details-marker{display:none}
.faq summary::after{content:'+';flex:none;width:30px;height:30px;border-radius:50%;border:1.5px solid var(--copper);color:var(--copper);display:flex;align-items:center;justify-content:center;font-size:19px;font-weight:600}
.faq details[open ] summary::after{content:'–'}
.faq .fans{padding:0 24px 20px;color:var(--muted);max-width:82ch}
.faq .fans p+p{margin-top:8px}

/* ---------- sources / byline ---------- */
.sources{margin-top:22px;background:#fff;border:1px solid var(--line);border-radius:14px;padding:20px 24px}
.sources .slabel{font-size:13px;font-weight:600;letter-spacing:.09em;text-transform:uppercase;color:var(--muted);display:block;margin-bottom:8px}
.sources ul{list-style:none}
.sources li{padding:5px 0;font-size:16px}
.sources a{font-weight:600}
.sources .snote{color:var(--muted);font-size:15px}
.byline{margin-top:18px;font-size:14.5px;color:var(--muted)}
.byline b{color:var(--ink);font-weight:600}

/* ---------- prose pages ---------- */
.prose p{margin-top:12px}
.prose ul,.prose ol{margin:12px 0 0 22px}
.prose li{margin-top:6px}
.prose h2{margin-top:38px}
.prose h2:first-child{margin-top:0}
.bigmail{display:inline-flex;align-items:center;gap:10px;background:var(--panel);color:#fff;font-weight:600;border-radius:12px;padding:14px 24px;min-height:52px;margin-top:16px}
.bigmail:hover{text-decoration:none;background:#17181D}
.bigmail .mono{color:var(--lcd);font-size:16px}
.checklist{background:#fff;border:1px solid var(--line);border-radius:14px;padding:20px 26px;margin-top:18px}
.checklist li{margin-top:8px}
.profilelinks{display:flex;gap:10px;flex-wrap:wrap;margin-top:16px}
.profilelinks a{background:#fff;border:1px solid var(--line);border-radius:999px;padding:9px 17px;font-weight:600;font-size:15px;min-height:44px;display:inline-flex;align-items:center}
.profilelinks a:hover{border-color:var(--copper);text-decoration:none}

/* ---------- answer list (chart page) ---------- */
.answers{display:grid;grid-template-columns:1fr 1fr;gap:12px;margin-top:22px}
.acard{background:var(--card);border:1px solid var(--line);border-radius:13px;padding:16px 20px;font-size:16px}
.acard b{font-family:'Archivo',sans-serif}
.acard .mono{color:var(--copper);font-weight:700}

/* ---------- footer ---------- */
footer.site{background:var(--panel);color:#C9CBD2;margin-top:64px}
.fgrid{display:grid;grid-template-columns:1.4fr 1fr 1fr 1.1fr;gap:34px;padding:46px 0 34px}
.fbrand .logo{color:#fff}
.fbrand p{font-size:15px;margin-top:14px;max-width:310px}
.fbrand .built{margin-top:16px;font-size:14.5px;color:var(--consolemut)}
.fbrand .built a{color:#EDEBE4;font-weight:600}
.fbrand .prow{display:flex;gap:8px;flex-wrap:wrap;margin-top:14px}
.fbrand .prow a{border:1px solid #41444E;color:#C9CBD2;border-radius:999px;padding:7px 14px;font-size:14px;font-weight:500;min-height:38px;display:inline-flex;align-items:center}
.fbrand .prow a:hover{color:#fff;border-color:#9B9EA8;text-decoration:none}
.fcol .fch{font-family:'Archivo',sans-serif;color:#fff;font-size:15px;font-weight:700;letter-spacing:.07em;text-transform:uppercase;margin-bottom:14px}
.fcol a{display:block;color:#C9CBD2;font-size:15.5px;padding:5px 0}
.fcol a:hover{color:#fff}
.fcol p{font-size:15.5px;padding:5px 0}
.fcol .mail{color:var(--lcd);font-family:'JetBrains Mono',monospace;font-size:14.5px}
.fcol .rep{color:var(--lcd);font-weight:600;display:inline;padding:0}
.bottomline{border-top:1px solid #3A3D45;padding:18px 0;font-size:14.5px;color:var(--consolemut);display:flex;justify-content:space-between;gap:14px;flex-wrap:wrap}

/* ---------- back to top ---------- */
.totop{position:fixed;right:22px;bottom:22px;width:46px;height:46px;border-radius:50%;background:var(--copper);color:#fff;border:0;cursor:pointer;display:none;align-items:center;justify-content:center;box-shadow:0 8px 22px rgba(28,27,23,.30);z-index:55}
.totop.show{display:flex}
.totop:hover{background:var(--copper-dark)}

/* ---------- mobile ---------- */
@media (max-width:920px){
  nav.mainnav{display:none}
  .burger{display:flex}
  .cards3,.calcgrid{grid-template-columns:1fr 1fr}
  .fgrid{grid-template-columns:1fr 1fr}
}
@media (max-width:640px){
  body{font-size:16.5px}
  .wrap{padding:0 18px}
  .hero{padding:38px 0 20px}
  .hero h1{font-size:36px;text-align:center}
  .hero.left h1{font-size:32px}
  .hero p.sub{text-align:center}
  .hero.left p.sub{text-align:left}
  .hero .trust{justify-content:center}
  .hero.left .trust{justify-content:flex-start}
  h2{font-size:26px}
  .console{padding:24px 18px 22px;border-radius:16px}
  .cgrid,.cgrid.c2{grid-template-columns:minmax(0,1fr);gap:18px}
  .lcd{font-size:48px}
  .readouts2{grid-template-columns:1fr}
  .readouts2 .lcd{font-size:42px}
  .formula-line{font-size:13.5px}
  .qa-grid{grid-template-columns:1fr}
  .cards3,.cards2,.calcgrid,.answers{grid-template-columns:1fr}
  .fgrid{grid-template-columns:1fr;gap:26px}
  th,td{padding:10px 12px;font-size:14.5px}
  td{font-size:14px}
  .pfband,.example{padding:22px 20px}
  .bottomline{justify-content:center;text-align:center}
  .faq summary{padding:17px 18px;font-size:16.5px}
  .faq .fans{padding:0 18px 18px}
}

/* ---------- print (chart) ---------- */
@page{size:A4;margin:12mm}
@media print{
  header.site,footer.site,.totop,.console,.chart-actions,.crumbs,.noprint,.toc,.pills{display:none !important}
  body{background:#fff;color:#000;font-size:12.5px}
  .wrap{max-width:none;padding:0}
  .hero{padding:6px 0 10px}
  .hero h1{font-size:30px}
  section{padding:10px 0}
  .tablewrap{border:0;border-radius:0}
  .tablescroll{overflow:visible}
  table{width:100%;font-size:11px}
  th,td{padding:5px 6px;white-space:normal}
  th{background:#fff;border-bottom:2px solid #000;color:#000}
  td{color:#000}
  a{color:#000}
  .answers .acard{border-color:#999}
  tr{break-inside:avoid}
}