:root{--bg:#06111f;--bg-soft:#0a192a;--panel:#0d1d30;--panel-2:#11243a;--line:rgba(255,255,255,.11);--text:#f3f7fb;--muted:#9fb0c3;--accent:#7ee7b7;--accent-2:#72b8ff;--warning:#ffd280;--danger:#ff9f9f;--shadow:0 24px 70px rgba(0,0,0,.28);--radius:20px}
*{box-sizing:border-box}
html{scroll-behavior:smooth}
body{margin:0;background:radial-gradient(circle at 82% 4%,rgba(71,132,196,.14),transparent 27rem),radial-gradient(circle at 12% 18%,rgba(71,196,147,.08),transparent 25rem),var(--bg);color:var(--text);font-family:Inter,ui-sans-serif,system-ui,-apple-system,BlinkMacSystemFont,"Segoe UI",sans-serif;line-height:1.55}
button,input,select{font:inherit}
button{cursor:pointer}
a{color:inherit}
h1,h2,h3,p{margin-top:0}
.eyebrow,.step{color:var(--accent);font-size:.72rem;font-weight:850;letter-spacing:.16em;text-transform:uppercase;margin:0 0 10px}

/* header / nav / breadcrumbs, matching the rest of the site */
.site-header{width:min(1440px,calc(100% - 40px));margin:0 auto;height:82px;display:flex;align-items:center;justify-content:space-between;border-bottom:1px solid var(--line)}
.brand{display:inline-flex;align-items:center;text-decoration:none;flex:0 0 auto}
.brand-logo{display:block;width:228px;height:auto;max-width:228px;object-fit:contain}
.site-header nav{display:flex;gap:28px}
.site-header nav a{text-decoration:none;color:var(--muted);font-size:.92rem}
.site-header nav a:hover{color:var(--text)}
.site-header nav a[aria-current="page"]{color:var(--accent)}
main{width:min(1160px,calc(100% - 40px));margin:0 auto}
.breadcrumbs{display:flex;align-items:center;gap:8px;padding-top:20px;color:#7f92a7;font-size:.72rem}
.breadcrumbs a{color:var(--muted);text-decoration:none}
.breadcrumbs a:hover{color:var(--text)}
.mobile-breadcrumbs{display:none}

/* hero */
.hero{padding:52px 0 34px}
h1{font-size:clamp(2.2rem,5vw,3.7rem);letter-spacing:-.05em;line-height:1;margin-bottom:20px;max-width:860px}
.lede{color:#c4d1de;font-size:clamp(1.02rem,2vw,1.2rem);max-width:760px;margin-bottom:20px}
.hero-trust{display:grid;gap:7px;color:#c8d5e2;font-size:.84rem;margin-bottom:18px}
.hero-trust span::first-letter{color:var(--accent)}
.tool-meta{display:flex;gap:10px;flex-wrap:wrap;color:#8093a8;font-size:.7rem;margin-bottom:16px}
.tool-meta span,.tool-meta a{padding:5px 8px;border:1px solid rgba(255,255,255,.09);border-radius:999px}
.tool-meta a{color:var(--accent);text-decoration:none}
.hero-notice{padding:15px 17px;border:1px solid rgba(126,231,183,.26);background:rgba(126,231,183,.06);border-radius:12px;color:var(--muted);font-size:.86rem;max-width:900px}
.hero-notice strong{color:var(--text)}

/* generic section heading */
.section-heading{display:flex;justify-content:space-between;align-items:flex-end;gap:16px;flex-wrap:wrap;margin-bottom:16px}
.section-heading h2{font-size:clamp(1.3rem,2.4vw,1.7rem);letter-spacing:-.03em;margin:0 0 4px}
.section-heading p{color:var(--muted);font-size:.86rem;margin:0;max-width:680px}

/* shell: inputs stacked, results sticky alongside */
.finder-shell{display:grid;grid-template-columns:minmax(360px,1fr) minmax(320px,.85fr);gap:22px;align-items:start;margin:6px 0 40px}
.inputs-panel{display:flex;flex-direction:column;gap:18px}
.card{border:1px solid var(--line);border-radius:var(--radius);background:rgba(10,25,42,.84);box-shadow:var(--shadow);padding:24px}
.results-panel{position:sticky;top:20px;border:1px solid var(--line);border-radius:var(--radius);background:rgba(10,25,42,.84);box-shadow:var(--shadow);padding:26px}

/* option buttons */
.option-grid{display:grid;gap:8px}
.option-grid.cols-2{grid-template-columns:repeat(2,1fr)}
.option-grid.cols-3{grid-template-columns:repeat(3,1fr)}
.option-grid.cols-4{grid-template-columns:repeat(4,1fr)}
.option-btn{border:1px solid var(--line);border-radius:12px;background:transparent;color:var(--text);padding:13px 12px;text-align:left}
.option-btn strong{display:block;font-size:.86rem;margin-bottom:3px}
.option-btn small{display:block;color:var(--muted);font-size:.7rem;line-height:1.4}
.option-btn.active{border-color:var(--accent);background:rgba(126,231,183,.1)}
.option-btn.active small{color:#bfe9d5}

.field{display:block;min-width:0;margin-bottom:14px}
.field:last-child{margin-bottom:0}
.field>span:first-child{display:block;color:var(--muted);font-size:.78rem;margin:0 0 6px 2px}
.field>span:first-child small{display:block;color:#71859a;font-size:.68rem;line-height:1.4;margin-top:2px;font-weight:400}
.input-wrap{display:flex;align-items:center;border:1px solid var(--line);background:rgba(255,255,255,.025);border-radius:10px;overflow:hidden}
.input-wrap:focus-within{border-color:rgba(126,231,183,.65);box-shadow:0 0 0 3px rgba(126,231,183,.08)}
.input-wrap i{color:#8194a9;font-style:normal;font-size:.72rem;white-space:nowrap;padding:0 10px}
.input-wrap input,.input-wrap select{width:100%;min-width:0;border:0;outline:0;color:var(--text);background:transparent;padding:11px 10px;font-size:1rem}
.field-row{display:grid;grid-template-columns:1fr 1fr;gap:10px}
.field-note{color:#71859a;font-size:.72rem;line-height:1.5;margin:6px 2px 0}

.meter-result{font-size:.8rem;color:var(--muted);padding:10px 12px;border:1px dashed rgba(255,255,255,.16);border-radius:10px}
.meter-result strong{color:var(--accent)}

.assumptions-note{margin-top:2px}
.assumptions-note summary{list-style:none;cursor:pointer;color:var(--muted);font-size:.78rem;padding:6px 0}
.assumptions-note summary::-webkit-details-marker{display:none}
.assumptions-note summary::before{content:"+ ";color:var(--accent)}
.assumptions-note[open] summary::before{content:"\2013 "}
.assumptions-list{color:var(--muted);font-size:.78rem;line-height:1.7;margin:6px 0 0;padding-left:0;list-style:none}
.assumptions-list li{border-top:1px solid rgba(255,255,255,.07);padding:6px 0}

/* results */
.results-heading h2{font-size:clamp(1.25rem,2.4vw,1.6rem);letter-spacing:-.03em;line-height:1.2;margin-bottom:16px}

.verdict-card{padding:18px 19px;border-radius:16px;margin-bottom:14px;border:1px solid var(--line);background:rgba(255,255,255,.025)}
.verdict-card .verdict-label{font-size:.7rem;font-weight:800;text-transform:uppercase;letter-spacing:.05em;color:var(--muted);margin-bottom:6px}
.verdict-card .verdict-headline{font-size:clamp(1.2rem,2.6vw,1.5rem);letter-spacing:-.03em;margin-bottom:6px}
.verdict-card .verdict-sub{color:var(--muted);font-size:.85rem}
.verdict-good{background:linear-gradient(145deg,rgba(126,231,183,.18),rgba(126,231,183,.04));border-color:rgba(126,231,183,.4)}
.verdict-good .verdict-headline{color:var(--accent)}
.verdict-warn{background:linear-gradient(145deg,rgba(255,210,128,.18),rgba(255,210,128,.05));border-color:rgba(255,210,128,.4)}
.verdict-warn .verdict-headline{color:var(--warning)}
.verdict-bad{background:linear-gradient(145deg,rgba(255,159,159,.16),rgba(255,159,159,.05));border-color:rgba(255,159,159,.4)}
.verdict-bad .verdict-headline{color:var(--danger)}

/* boiler vs heat pump comparison */
.compare-grid{display:grid;grid-template-columns:1fr 1fr;gap:10px;margin-bottom:14px}
.compare-card{border:1px solid var(--line);border-radius:14px;padding:16px;background:rgba(255,255,255,.025)}
.compare-card .compare-label{color:var(--muted);font-size:.72rem;text-transform:uppercase;letter-spacing:.04em;font-weight:800;margin-bottom:6px}
.compare-card .compare-figure{font-size:clamp(1.15rem,2.4vw,1.45rem);letter-spacing:-.03em;margin-bottom:2px}
.compare-card .compare-sub{color:var(--muted);font-size:.74rem}
.compare-card.hp.cheaper{border-color:rgba(126,231,183,.32);background:rgba(126,231,183,.05)}
.compare-card.hp.cheaper .compare-figure{color:var(--accent)}
.compare-card.hp.pricier{border-color:rgba(255,159,159,.32);background:rgba(255,159,159,.05)}
.compare-card.hp.pricier .compare-figure{color:var(--danger)}

.result-cards{display:grid;grid-template-columns:1fr 1fr;gap:10px;margin-bottom:16px}
.result-card{padding:15px 16px;border:1px solid var(--line);border-radius:14px;background:rgba(255,255,255,.025)}
.result-card span{color:var(--muted);font-size:.72rem;display:block}
.result-card strong{font-size:clamp(1.05rem,2.2vw,1.3rem);letter-spacing:-.03em;display:block;margin-top:3px}

.export-note{display:flex;gap:10px;padding:13px 15px;border:1px solid rgba(255,210,128,.28);background:rgba(255,210,128,.06);border-radius:12px;color:var(--muted);font-size:.82rem;line-height:1.5;margin-bottom:16px}
.export-note strong{color:var(--text)}

.verdict{padding:16px 17px;background:var(--panel-2);border:1px solid var(--line);border-radius:14px;margin-bottom:14px}
.verdict h3{margin-bottom:6px;font-size:.98rem}
.verdict p{color:var(--muted);margin-bottom:0;font-size:.83rem}

.mistakes{border:1px solid rgba(255,210,128,.22);background:rgba(255,210,128,.05);border-radius:14px;padding:15px 16px;margin-bottom:14px}
.mistakes h3{font-size:.9rem;margin-bottom:8px;color:var(--text)}
.mistakes ul{margin:0;padding-left:18px;color:var(--muted);font-size:.78rem;line-height:1.6}
.mistakes li{margin-bottom:4px}

.crosslinks{display:flex;flex-direction:column;gap:8px;margin-bottom:14px}
.crosslink-card{display:flex;justify-content:space-between;align-items:center;gap:10px;border:1px solid rgba(114,184,255,.26);border-radius:12px;padding:12px 14px;text-decoration:none;color:var(--text);background:rgba(114,184,255,.04)}
.crosslink-card:hover{border-color:rgba(114,184,255,.5)}
.crosslink-card strong{display:block;font-size:.84rem}
.crosslink-card small{color:var(--muted);font-size:.7rem}
.crosslink-card i{color:var(--accent-2);font-style:normal}

.disclaimer{margin-top:4px;padding:13px 15px;border:1px solid rgba(255,210,128,.28);background:rgba(255,210,128,.06);border-radius:12px;color:var(--muted);font-size:.76rem;line-height:1.5}
.disclaimer strong{color:var(--text)}

/* helps/hurts explainer */
.explainer-section{padding:10px 0 20px}
.explainer-grid{display:grid;grid-template-columns:1fr 1fr;gap:16px;margin:18px 0 4px}
.explainer-col{border:1px solid var(--line);border-radius:14px;padding:18px}
.explainer-col.counts{border-color:rgba(126,231,183,.3);background:rgba(126,231,183,.04)}
.explainer-col.doesnt{border-color:rgba(255,159,159,.3);background:rgba(255,159,159,.04)}
.explainer-col h3{font-size:.92rem;margin-bottom:10px}
.explainer-col ul{margin:0;padding-left:18px;color:var(--muted);font-size:.82rem;line-height:1.65}
.explainer-col li{margin-bottom:6px}
.explainer-col li strong{color:var(--text)}

/* status section (grant details) */
.status-section{padding:10px 0 20px}
.status-grid{display:grid;grid-template-columns:repeat(auto-fit,minmax(230px,1fr));gap:14px;margin:18px 0 16px}
.status-item{border-left:3px solid var(--accent);padding:2px 0 2px 14px}
.status-item strong{display:block;font-size:.88rem;margin-bottom:4px;color:var(--text)}
.status-item span{color:var(--muted);font-size:.82rem;line-height:1.5}
.fine-print{color:#7f92a7;font-size:.74rem;line-height:1.6;max-width:840px}
.fine-print a{color:var(--accent-2)}

/* methodology / version history, shared pattern */
.methodology-section{padding:10px 0 20px}
details.methodology{border-top:1px solid var(--line);border-bottom:1px solid var(--line);padding:2px 0}
details.methodology summary{list-style:none;padding:18px 0;font-weight:750;cursor:pointer;position:relative}
details.methodology summary::-webkit-details-marker{display:none}
details.methodology summary::after{content:"+";position:absolute;right:2px;color:var(--muted);font-size:1.2rem}
details.methodology[open] summary::after{content:"\2013"}
.method-copy{color:var(--muted);font-size:.86rem;max-width:840px;padding-bottom:18px}
.method-copy p{margin:0 0 10px}
.method-copy p:last-child{margin-bottom:0}

.version-history-collapsed{width:min(1160px,calc(100% - 40px));margin:0 auto;padding:0 0 10px}
.version-history-collapsed details{border-top:1px solid var(--line);border-bottom:1px solid var(--line)}
.version-history-collapsed summary{list-style:none;padding:16px 0;cursor:pointer;color:var(--muted);font-size:.86rem}
.version-history-collapsed summary::-webkit-details-marker{display:none}
.version-list{padding:4px 0 16px}
.version-list article{border-top:1px solid rgba(255,255,255,.07);padding:12px 0;display:grid;grid-template-columns:70px 1fr;gap:12px}
.version-list article span{color:var(--accent);font-size:.72rem;font-weight:800}
.version-list article strong{display:block;font-size:.86rem;margin-bottom:3px}
.version-list article p{color:var(--muted);font-size:.8rem;margin:0}

/* support considered */
.support-considered{margin:10px 0 40px;padding:24px;border:1px solid rgba(126,231,183,.22);border-radius:18px;background:radial-gradient(circle at 85% 0%,rgba(126,231,183,.09),transparent 22rem),rgba(255,255,255,.02)}
.support-intro{max-width:820px;margin-bottom:18px}
.support-intro h2{font-size:clamp(1.4rem,2.6vw,1.9rem);margin:6px 0 8px}
.support-intro>p:last-child{color:var(--muted);margin-bottom:0}
.support-grid{display:grid;grid-template-columns:repeat(4,1fr);gap:11px}
.support-card{display:grid;grid-template-columns:44px 1fr auto;gap:12px;align-items:center;min-width:0;padding:15px;border:1px solid rgba(255,255,255,.10);border-radius:12px;color:var(--text);text-decoration:none;transition:transform .18s ease,border-color .18s ease,filter .18s ease}
.support-card:hover{transform:translateY(-2px);border-color:rgba(255,255,255,.24);filter:brightness(1.04)}
.support-card>span:nth-child(2){display:flex;flex-direction:column;min-width:0}
.support-card strong{font-size:.88rem}
.support-card small{color:rgba(255,255,255,.72);font-size:.69rem;margin-top:3px}
.support-card i{color:rgba(255,255,255,.75);font-style:normal}
.support-icon{display:grid;place-items:center;width:42px;height:42px;border-radius:10px;background:rgba(0,0,0,.16);font-size:1.2rem}
.support-kofi{background:linear-gradient(135deg,rgba(231,65,87,.85),rgba(190,42,75,.82))}
.support-octopus{background:linear-gradient(135deg,rgba(143,56,216,.80),rgba(89,46,170,.80))}
.support-youtube{background:linear-gradient(135deg,rgba(211,31,31,.82),rgba(128,15,15,.82))}
.support-member{background:linear-gradient(135deg,rgba(28,105,177,.82),rgba(18,61,118,.82))}
.support-disclosure{color:#8194a9;font-size:.69rem;margin:14px 0 0}

footer{width:min(1440px,calc(100% - 40px));margin:0 auto;padding:36px 0 56px;border-top:1px solid var(--line);display:flex;justify-content:space-between;color:var(--muted)}
footer strong{color:var(--text);letter-spacing:.16em}
footer p{font-size:.82rem;margin-top:8px}
footer>div:last-child{display:flex;gap:22px;align-items:flex-start}
footer a{text-decoration:none;font-size:.82rem}
footer a:hover{color:var(--text)}

@media(max-width:1000px){
  .finder-shell{grid-template-columns:1fr}
  .results-panel{position:static}
  .explainer-grid{grid-template-columns:1fr}
}
@media(max-width:700px){
  .site-header{width:min(100% - 24px,1440px);height:70px}
  .site-header nav a{display:none}.site-header nav a.member-link{display:inline-flex!important}
  .brand-logo{width:185px}
  main,footer,.version-history-collapsed{width:min(100% - 24px,1440px)}
  .breadcrumbs{display:none}
  .mobile-breadcrumbs{display:flex;padding-top:16px}
  .mobile-breadcrumbs a{color:var(--muted);text-decoration:none;font-size:.8rem}
  h1{font-size:2.2rem}
  .option-grid.cols-4{grid-template-columns:1fr 1fr}
  .option-grid.cols-3{grid-template-columns:1fr 1fr}
  .option-grid.cols-2{grid-template-columns:1fr}
  .result-cards{grid-template-columns:1fr}
  .compare-grid{grid-template-columns:1fr}
  .field-row{grid-template-columns:1fr}
  .support-grid{grid-template-columns:1fr}
  footer{flex-direction:column;gap:20px}
}