:root{
  --ink:#14211d;--muted:#55645f;--line:#dfe6e2;--bg:#f6f8f6;--card:#fff;
  --brand:#0f5c4a;--brand-dark:#0a4034;--accent:#ffd166;--soft:#e8f3ef;
  --radius:12px;--max:1040px;
}
*{box-sizing:border-box}
html{-webkit-text-size-adjust:100%;scroll-behavior:smooth}
body{margin:0;background:var(--bg);color:var(--ink);font:17px/1.65 system-ui,-apple-system,"Segoe UI",Roboto,"Helvetica Neue",Arial,sans-serif}
.wrap{max-width:var(--max);margin:0 auto;padding:0 20px}
a{color:var(--brand);text-underline-offset:3px}
a:hover{color:var(--brand-dark)}
:focus-visible{outline:3px solid var(--accent);outline-offset:2px}
.skip{position:absolute;left:-999px}
.skip:focus{left:12px;top:12px;background:#fff;padding:8px 12px;z-index:10}
.ico{width:22px;height:22px;flex:none}

/* header */
.site-header{background:var(--brand);color:#fff;position:sticky;top:0;z-index:5}
.bar{display:flex;align-items:center;justify-content:space-between;min-height:60px;gap:16px}
.logo{display:inline-flex;align-items:center;gap:8px;font-weight:800;font-size:1.2rem;color:#fff;text-decoration:none;letter-spacing:-.01em}
.logo .ico{color:var(--accent);fill:var(--accent);stroke:none}
.nav{display:flex;gap:4px;flex-wrap:wrap}
.nav a{color:#fff;text-decoration:none;padding:8px 12px;border-radius:8px;font-size:.95rem;font-weight:500}
.nav a:hover,.nav a[aria-current]{background:rgba(255,255,255,.14);color:#fff}
.menu-btn{display:none;background:none;border:1px solid rgba(255,255,255,.5);color:#fff;border-radius:8px;padding:7px 12px;font:inherit;font-size:.95rem}

/* type */
main.wrap{padding-top:22px;padding-bottom:64px}
h1{font-size:clamp(1.7rem,4.2vw,2.5rem);line-height:1.15;letter-spacing:-.02em;margin:.4em 0 .35em}
h2{font-size:clamp(1.25rem,2.6vw,1.55rem);line-height:1.25;letter-spacing:-.01em;margin:2em 0 .5em}
p{margin:0 0 1em}
article p,article li,.prose p{max-width:72ch}
ul{padding-left:1.2em;margin:0 0 1em}
li{margin-bottom:.4em}
.crumbs{font-size:.85rem;color:var(--muted);margin-bottom:4px}
.crumbs a{color:var(--muted)}
.byline{font-size:.88rem;color:var(--muted);margin-bottom:1.2em}
.answer{font-size:1.1rem;background:var(--soft);border-left:4px solid var(--brand);padding:14px 18px;border-radius:0 var(--radius) var(--radius) 0;max-width:none!important}
.hero .answer{background:none;border:0;padding:0;color:var(--muted);max-width:62ch!important}
.hint{font-size:.88rem;color:var(--muted)}
.formula{font:600 1.05rem/1.5 ui-monospace,SFMono-Regular,Menlo,Consolas,monospace;background:var(--card);border:1px solid var(--line);border-radius:var(--radius);padding:14px 18px;overflow-x:auto;white-space:nowrap}

/* calculator */
.calc{background:var(--card);border:1px solid var(--line);border-radius:16px;padding:22px;margin:22px 0 28px;box-shadow:0 2px 14px rgba(15,92,74,.07)}
.calc h2{margin:0 0 14px;font-size:1.2rem}
.calc-form{display:grid;grid-template-columns:repeat(auto-fit,minmax(170px,1fr));gap:14px}
.calc-form label{display:flex;flex-direction:column;gap:6px;font-size:.85rem;font-weight:600;color:var(--muted)}
.calc-form input,.calc-form select{font:inherit;font-size:1.05rem;color:var(--ink);padding:10px 12px;border:1.5px solid var(--line);border-radius:10px;background:#fff;width:100%;min-height:46px}
.calc-form input:focus,.calc-form select:focus{border-color:var(--brand);outline:none;box-shadow:0 0 0 3px var(--soft)}
.calc .hint{margin:12px 0 0}
.results{display:grid;grid-template-columns:repeat(4,1fr);gap:10px;margin-top:18px}
.results div{background:var(--soft);border-radius:12px;padding:14px 12px;text-align:center}
.results span{display:block;font-size:.8rem;color:var(--muted);font-weight:600;text-transform:uppercase;letter-spacing:.04em}
.results strong{display:block;font-size:1.45rem;line-height:1.3;font-variant-numeric:tabular-nums}
.results .big{background:var(--brand);color:#fff}
.results .big span{color:#cfe6de}
.kwh{font-size:.88rem;color:var(--muted);margin:14px 0 0;max-width:none}

/* cards */
.cards{display:grid;grid-template-columns:repeat(auto-fill,minmax(215px,1fr));gap:12px;margin:14px 0 8px}
.cards.one{grid-template-columns:1fr}
.card{display:flex;flex-direction:column;gap:4px;background:var(--card);border:1px solid var(--line);border-radius:var(--radius);padding:16px;text-decoration:none;color:var(--ink);transition:transform .15s,border-color .15s,box-shadow .15s}
.card:hover{transform:translateY(-2px);border-color:var(--brand);box-shadow:0 6px 18px rgba(15,92,74,.1);color:var(--ink)}
.card .ico{color:var(--brand);width:26px;height:26px;margin-bottom:4px}
.card b{font-size:1.02rem}
.card span{font-size:.85rem;color:var(--muted)}
.card.wide b{font-size:1.15rem;color:var(--brand)}

/* tables */
.tablewrap{overflow-x:auto;background:var(--card);border:1px solid var(--line);border-radius:var(--radius);margin:0 0 1em}
.tablewrap.tall{max-height:520px;overflow-y:auto}
table{border-collapse:collapse;width:100%;font-size:.95rem;font-variant-numeric:tabular-nums}
th,td{padding:10px 14px;text-align:right;border-bottom:1px solid var(--line);white-space:nowrap}
th:first-child,td:first-child{text-align:left}
thead th{background:var(--soft);font-size:.8rem;text-transform:uppercase;letter-spacing:.04em;color:var(--muted);position:sticky;top:0}
tbody tr:last-child td{border-bottom:0}
tbody tr:hover{background:#fafcfb}
.two{display:grid;grid-template-columns:1fr 1fr;gap:14px}

/* faq */
.faq details{background:var(--card);border:1px solid var(--line);border-radius:var(--radius);padding:0 18px;margin-bottom:10px}
.faq summary{cursor:pointer;font-weight:650;padding:14px 0;list-style-position:outside}
.faq details p{margin:0 0 16px;color:#2c3a36}

/* footer */
.site-footer{background:#10201c;color:#b9c7c2;padding:40px 0 22px;font-size:.92rem}
.fgrid{display:grid;grid-template-columns:1.6fr 1fr 1fr 1fr;gap:28px}
.site-footer h2{font-size:.8rem;text-transform:uppercase;letter-spacing:.08em;color:#fff;margin:0 0 10px}
.site-footer a{color:#b9c7c2;display:block;text-decoration:none;padding:3px 0}
.site-footer a:hover{color:#fff;text-decoration:underline}
.site-footer .logo{display:inline-flex;margin-bottom:8px;color:#fff}
.fine{border-top:1px solid #253a34;margin-top:26px;padding-top:16px;font-size:.82rem;color:#8ea09a}

@media (max-width:760px){
  body{font-size:16px}
  .menu-btn{display:block}
  .nav{display:none;position:absolute;left:0;right:0;top:60px;background:var(--brand-dark);flex-direction:column;padding:8px 14px 14px}
  .nav.open{display:flex}
  .nav a{padding:12px}
  .results{grid-template-columns:1fr 1fr}
  .results strong{font-size:1.25rem}
  .two{grid-template-columns:1fr}
  .fgrid{grid-template-columns:1fr 1fr}
  .calc{padding:16px}
  th,td{padding:9px 10px}
}
@media (prefers-reduced-motion:reduce){html{scroll-behavior:auto}.card{transition:none}}
@media print{.site-header,.site-footer,.calc-form{display:none}}

/* plain-English helper */
.ask{background:var(--soft);border-radius:12px;padding:14px 16px;margin-bottom:18px}
.ask label{display:block;font-size:.9rem;font-weight:650;margin-bottom:8px}
.ask-row{display:flex;gap:8px}
.ask-row input{flex:1;min-width:0;font:inherit;padding:10px 12px;border:1.5px solid var(--line);border-radius:10px;min-height:46px;background:#fff;color:var(--ink)}
.ask-row input:focus{border-color:var(--brand);outline:none;box-shadow:0 0 0 3px #fff}
.ask-row button{font:inherit;font-weight:650;background:var(--brand);color:#fff;border:0;border-radius:10px;padding:0 18px;cursor:pointer;white-space:nowrap}
.ask-row button:hover{background:var(--brand-dark)}
.chips{display:flex;flex-wrap:wrap;gap:6px;margin-top:10px}
.chips button{font:inherit;font-size:.82rem;background:#fff;border:1px solid var(--line);border-radius:999px;padding:5px 12px;cursor:pointer;color:var(--ink)}
.chips button:hover{border-color:var(--brand);color:var(--brand)}
.ask-out{margin:12px 0 0;font-size:.95rem;max-width:none}
.ask-out:empty{display:none}
.flash{animation:flash 1s ease-out}
@keyframes flash{from{box-shadow:0 0 0 4px var(--accent)}to{box-shadow:0 0 0 0 transparent}}
@media (max-width:760px){.ask-row{flex-direction:column}.ask-row button{min-height:44px}}