/* suntellventilation.com */
:root{
  --ink:#17222C;--ink-2:#44525E;--slate:#243B4F;--slate-2:#1B2D3D;--paper:#F2F6F8;--white:#FFFFFF;
  --air:#2A8DBF;--air-2:#1F6E97;--signal:#E8792B;--signal-2:#C9631D;--line:#CFD9E0;--line-2:#E3EAEF;
  --on-slate:#F2F6F8;--on-slate-2:#B9C8D4;
  --font:"Barlow",system-ui,-apple-system,"Segoe UI",Roboto,Helvetica,Arial,sans-serif;
  --display:"Barlow Semi Condensed","Barlow",system-ui,-apple-system,"Segoe UI",Roboto,Helvetica,Arial,sans-serif;
  --max:1120px;--gutter:24px;--radius:4px;
  color-scheme:light dark;
}
@media (prefers-color-scheme:dark){
  :root{--ink:#E6EDF2;--ink-2:#A9B8C4;--slate:#16242F;--slate-2:#0F1A22;--paper:#0F1A22;--white:#16242F;
    --air:#6CBDE6;--air-2:#8FD0F0;--line:#2A3B48;--line-2:#223240;--on-slate:#E6EDF2;--on-slate-2:#A9B8C4;}
}
*,*::before,*::after{box-sizing:border-box}
html{-webkit-text-size-adjust:100%;scroll-behavior:smooth}
@media (prefers-reduced-motion:reduce){html{scroll-behavior:auto}}
body{margin:0;font-family:var(--font);font-size:16px;line-height:1.55;color:var(--ink);background:var(--paper);-webkit-font-smoothing:antialiased}
img,svg{display:block;max-width:100%;height:auto}
a{color:var(--air-2);text-decoration-thickness:1px;text-underline-offset:2px}
a:hover{color:var(--air)}
:focus-visible{outline:3px solid var(--air);outline-offset:2px}
h1,h2,h3,h4{font-family:var(--display);font-weight:600;line-height:1.1;margin:0 0 .5em;letter-spacing:-.005em}
h1{font-size:clamp(2.25rem,5.5vw,3.5rem)}
h2{font-size:clamp(1.65rem,3.4vw,2.1rem)}
h3{font-size:1.35rem}
h4{font-size:1.1rem;font-family:var(--font);font-weight:600}
p,ul,ol,table{margin:0 0 1em}
p.lead{font-size:1.15rem;color:var(--ink-2);max-width:62ch}
.measure{max-width:66ch}
.wrap{max-width:var(--max);margin:0 auto;padding:0 var(--gutter)}
.skip{position:absolute;left:-999px;top:0;background:var(--signal);color:#17222C;padding:8px 12px;z-index:100}
.skip:focus{left:8px;top:8px}
/* header */
.hdr{background:var(--white);border-bottom:1px solid var(--line)}
.hdr .wrap{display:flex;align-items:center;justify-content:space-between;min-height:64px;gap:16px}
.brand{font-family:var(--display);font-weight:700;font-size:1.5rem;letter-spacing:.01em;color:var(--ink);text-decoration:none;display:flex;align-items:center;gap:10px}
.brand .mark{width:28px;height:28px;flex:none}
.brand span{line-height:1}
.brand small{display:block;font-family:var(--font);font-weight:500;font-size:.68rem;color:var(--ink-2);letter-spacing:.02em;margin-top:2px}
.nav{display:none;gap:4px;align-items:center}
.nav a{color:var(--ink);text-decoration:none;padding:8px 10px;font-weight:500;font-size:.95rem;border-radius:var(--radius)}
.nav a:hover{background:var(--paper)}
.nav a[aria-current=page]{box-shadow:inset 0 -2px 0 var(--signal)}
.nav .cta{background:var(--signal);color:#17222C;margin-left:6px}
.nav .cta:hover{background:#F08A3E}
.menu-btn{display:inline-flex;align-items:center;gap:8px;background:none;border:1px solid var(--line);color:var(--ink);font:inherit;font-weight:500;padding:8px 12px;border-radius:var(--radius);cursor:pointer}
.menu-btn svg{width:18px;height:18px}
.mnav{display:none;background:var(--white);border-bottom:1px solid var(--line)}
.mnav.open{display:block}
.mnav a{display:block;padding:14px var(--gutter);border-top:1px solid var(--line-2);color:var(--ink);text-decoration:none;font-weight:500}
.mnav a.cta{color:var(--signal-2);font-weight:600}
@media (min-width:980px){.nav{display:flex}.menu-btn{display:none}.mnav{display:none!important}}
/* buttons */
.btn{display:inline-block;font:inherit;font-weight:600;padding:12px 20px;border-radius:var(--radius);text-decoration:none;border:1px solid transparent;cursor:pointer;line-height:1.2}
.btn-primary{background:var(--signal);color:#17222C;border-color:var(--signal)}
.btn-primary:hover{background:#F08A3E;border-color:#F08A3E;color:#17222C}
.btn-quiet{background:transparent;color:var(--ink);border-color:var(--line)}
.btn-quiet:hover{border-color:var(--ink-2);color:var(--ink)}
.btn-on-slate{background:transparent;color:var(--on-slate);border-color:var(--on-slate-2)}
.btn-on-slate:hover{color:#fff;border-color:#fff}
.btn-row{display:flex;flex-wrap:wrap;gap:12px;margin-top:20px}
/* sections */
.sec{padding:56px 0}
.sec-tight{padding:36px 0}
.sec-slate{background:var(--slate);color:var(--on-slate)}
.sec-slate h1,.sec-slate h2,.sec-slate h3{color:#fff}
.sec-slate p{color:var(--on-slate)}
.sec-slate a{color:#fff}
.sec-slate a.btn-primary{color:#17222C}
.h3{font-size:1.35rem;margin-top:0}
.sec-white{background:var(--white)}
.sec-rule{border-top:1px solid var(--line)}
.two{display:grid;gap:32px}
@media (min-width:800px){.two{grid-template-columns:1fr 1fr;align-items:start}.two.wide-l{grid-template-columns:3fr 2fr}.two.wide-r{grid-template-columns:2fr 3fr}}
.three{display:grid;gap:28px}
@media (min-width:800px){.three{grid-template-columns:repeat(3,1fr)}}
/* hero */
.hero{padding:48px 0 40px}
.hero h1{max-width:16ch}
.hero .lead{font-size:1.2rem}
.hero-grid{display:grid;gap:28px;align-items:center}
@media (min-width:860px){.hero-grid{grid-template-columns:1.05fr .95fr;gap:48px}.hero{padding:72px 0 56px}}
.product-stage{background:var(--white);border:1px solid var(--line);padding:24px;border-radius:var(--radius)}
.product-stage img{margin:0 auto;width:100%;max-width:520px}
.product-stage figcaption{font-size:.85rem;color:var(--ink-2);margin-top:12px;text-align:center}
/* big numbers */
.bignums{display:grid;grid-template-columns:repeat(2,1fr);gap:0;border-top:1px solid var(--line);border-bottom:1px solid var(--line)}
@media (min-width:700px){.bignums{grid-template-columns:repeat(4,1fr)}}
.bignum{padding:22px 16px 20px;border-right:1px solid var(--line)}
.bignum:nth-child(2n){border-right:0}
@media (min-width:700px){.bignum:nth-child(2n){border-right:1px solid var(--line)}.bignum:last-child{border-right:0}}
.bignum b{display:block;font-family:var(--display);font-weight:700;font-size:clamp(2.6rem,7vw,4.25rem);line-height:1;letter-spacing:-.02em}
.bignum b small{font-size:.38em;font-weight:600;margin-left:4px;letter-spacing:0;color:var(--ink-2)}
.bignum span{display:block;color:var(--ink-2);font-size:.9rem;margin-top:6px}
/* spec table */
.spec{width:100%;border-collapse:collapse;background:var(--white);border:1px solid var(--line)}
.spec th,.spec td{text-align:left;padding:12px 14px;border-top:1px solid var(--line);vertical-align:top;font-size:.97rem}
.spec tr:first-child th,.spec tr:first-child td{border-top:0}
.spec th{width:38%;font-weight:500;color:var(--ink-2)}
.spec td{font-weight:500}
.spec caption{text-align:left;font-family:var(--display);font-weight:600;font-size:1.2rem;padding:0 0 10px}
/* compare table */
.cmp{width:100%;border-collapse:collapse;background:var(--white);border:1px solid var(--line);font-size:.95rem}
.cmp th,.cmp td{text-align:left;padding:11px 12px;border-top:1px solid var(--line);vertical-align:top}
.cmp thead th{border-top:0;background:var(--paper);font-weight:600}
.cmp thead th:first-child{width:28%}
.cmp td:nth-child(2){font-weight:600}
.table-scroll{overflow-x:auto;-webkit-overflow-scrolling:touch}
/* steps (real sequences only) */
.steps{list-style:none;padding:0;margin:0;counter-reset:step}
.steps li{position:relative;padding:0 0 22px 58px;counter-increment:step}
.steps li::before{content:counter(step);position:absolute;left:0;top:-2px;width:40px;height:40px;border-radius:50%;background:var(--slate);color:#fff;font-family:var(--display);font-weight:700;font-size:1.2rem;display:flex;align-items:center;justify-content:center}
.sec-slate .steps li::before{background:var(--air);color:var(--slate-2)}
.steps h3{margin-bottom:.25em}
.steps p{margin:0;color:var(--ink-2)}
.sec-slate .steps p{color:var(--on-slate-2)}
/* panels */
.panel{background:var(--white);border:1px solid var(--line);border-top:3px solid var(--slate);padding:22px;border-radius:0 0 var(--radius) var(--radius)}
.panel h3{margin-top:0}
.panel-air{border-top-color:var(--air)}
.list-plain{list-style:none;padding:0}
.list-plain li{padding:10px 0;border-top:1px solid var(--line)}
.list-plain li:first-child{border-top:0}
.checks{list-style:none;padding:0}
.checks li{padding:6px 0 6px 28px;position:relative}
.checks li::before{content:"";position:absolute;left:2px;top:13px;width:14px;height:8px;border-left:2.5px solid var(--air);border-bottom:2.5px solid var(--air);transform:rotate(-45deg)}
/* figures */
figure{margin:0}
.photo{position:relative;background:var(--line-2)}
.photo img{width:100%;height:auto}
figcaption.illus{font-size:.8rem;color:var(--ink-2);margin-top:8px}
.photo-band{display:grid;gap:10px;grid-template-columns:repeat(2,1fr)}
@media (min-width:800px){.photo-band{grid-template-columns:repeat(3,1fr)}}
/* diagram */
.diagram{width:100%;max-width:960px;margin:0 auto}
.diagram text{font-family:var(--font);font-size:15px;fill:var(--on-slate)}
.diagram .lbl{font-weight:600;font-size:16px;fill:#fff}
.diagram .sub{font-size:13px;fill:var(--on-slate-2)}
.diagram .house{fill:none;stroke:var(--on-slate);stroke-width:3;stroke-linejoin:round}
.diagram .ground{stroke:var(--on-slate-2);stroke-width:2}
.diagram .unit{fill:#111A22;stroke:var(--on-slate);stroke-width:2}
.diagram .vent{stroke:var(--on-slate-2);stroke-width:2;stroke-dasharray:4 4}
.diagram .supply{fill:none;stroke:var(--air);stroke-width:4;stroke-linecap:round}
.diagram .supply-thin{fill:none;stroke:var(--air);stroke-width:3;stroke-linecap:round;opacity:.85}
.diagram .stale{fill:none;stroke:#D9A66B;stroke-width:3;stroke-linecap:round;stroke-dasharray:8 7}
.diagram .num circle{fill:var(--air)}
.diagram .num text{fill:var(--slate-2);font-weight:700;font-family:var(--display);font-size:17px}
.diagram .key rect{stroke:none}
.diagram.animate .supply,.diagram.animate .supply-thin{stroke-dasharray:1200;stroke-dashoffset:1200;animation:draw 2.2s ease-out forwards}
.diagram.animate .supply-thin{animation-delay:1.1s}
.diagram.animate .stale{opacity:0;animation:fadein .8s ease-out 2.4s forwards}
@media (max-width:700px){.diagram .lbl,.diagram .sub,.diagram .key{display:none}.diagram .num circle{r:24px}.diagram .num text{font-size:26px}}
@keyframes draw{to{stroke-dashoffset:0}}
@keyframes fadein{to{opacity:1}}
@media (prefers-reduced-motion:reduce){.diagram.animate .supply,.diagram.animate .supply-thin,.diagram.animate .stale{animation:none;stroke-dashoffset:0;opacity:1}}
/* forms */
form .f{margin-bottom:16px}
label{display:block;font-weight:500;margin-bottom:6px}
label small{font-weight:400;color:var(--ink-2)}
input[type=text],input[type=email],input[type=tel],input[type=number],select,textarea{width:100%;font:inherit;padding:11px 12px;border:1px solid var(--line);border-radius:var(--radius);background:var(--white);color:var(--ink)}
input:focus,select:focus,textarea:focus{border-color:var(--air);outline:3px solid color-mix(in srgb,var(--air) 35%,transparent);outline-offset:0}
textarea{min-height:120px;resize:vertical}
.f-grid{display:grid;gap:0 20px}
@media (min-width:700px){.f-grid{grid-template-columns:1fr 1fr}}
.hp{position:absolute;left:-9999px;opacity:0;height:0;overflow:hidden}
.note{font-size:.9rem;color:var(--ink-2)}
/* references + footer */
.refs{border-top:1px solid var(--line);padding:22px 0 0;margin-top:48px;font-size:.86rem;color:var(--ink-2)}
.refs h2{font-size:1rem;font-family:var(--font);font-weight:600;color:var(--ink);margin-bottom:.4em}
.refs ol{padding-left:1.2em;margin:0}
.refs li{margin:4px 0}
.ftr{background:var(--slate);color:var(--on-slate-2);padding:40px 0 32px;margin-top:56px;font-size:.92rem}
.ftr .wrap{display:grid;gap:24px}
@media (min-width:800px){.ftr .wrap{grid-template-columns:2fr 1fr 1fr}}
.ftr a{color:var(--on-slate)}
.ftr p{margin:0 0 .6em}
.ftr .brand{color:#fff;margin-bottom:10px}
.ftr .brand small{color:var(--on-slate-2)}
.ftr ul{list-style:none;padding:0;margin:0}
.ftr li{margin:6px 0}
.ftr .legal{grid-column:1/-1;border-top:1px solid rgba(255,255,255,.14);padding-top:16px;font-size:.84rem}
/* breadcrumb */
.crumbs{font-size:.88rem;color:var(--ink-2);padding:18px 0 0}
.crumbs a{color:var(--ink-2)}
.crumbs span{margin:0 6px}
/* faq */
.faq details{border-top:1px solid var(--line);padding:4px 0}
.faq details:last-child{border-bottom:1px solid var(--line)}
.faq summary{cursor:pointer;font-weight:600;padding:12px 0;list-style:none;position:relative;padding-right:32px}
.faq summary::-webkit-details-marker{display:none}
.faq summary::after{content:"";position:absolute;right:8px;top:18px;width:10px;height:10px;border-right:2px solid var(--ink-2);border-bottom:2px solid var(--ink-2);transform:rotate(45deg);transition:transform .15s}
.faq details[open] summary::after{transform:rotate(225deg);top:22px}
.faq .ans{padding:0 0 16px;color:var(--ink-2);max-width:70ch}
/* size helper */
.helper{background:var(--white);border:1px solid var(--line);padding:22px;border-radius:var(--radius)}
.helper .out{margin-top:16px;padding:16px;background:var(--paper);border-left:4px solid var(--air);font-size:1rem}
.helper .out b{font-family:var(--display);font-size:1.6rem;font-weight:700}
.helper .out .warn{border-left-color:var(--signal)}
/* assistant */
.asst-btn{position:fixed;right:16px;bottom:16px;z-index:60;background:var(--slate);color:#fff;border:1px solid rgba(255,255,255,.2);font:inherit;font-weight:600;padding:12px 16px;border-radius:999px;cursor:pointer;box-shadow:0 6px 20px rgba(0,0,0,.25);display:flex;align-items:center;gap:8px}
.asst-btn svg{width:18px;height:18px}
.asst{position:fixed;right:16px;bottom:72px;width:min(380px,calc(100vw - 32px));max-height:min(620px,calc(100vh - 100px));background:var(--white);border:1px solid var(--line);border-radius:8px;box-shadow:0 16px 48px rgba(0,0,0,.3);z-index:61;display:none;flex-direction:column;overflow:hidden}
.asst.open{display:flex}
.asst-h{background:var(--slate);color:#fff;padding:12px 14px;display:flex;align-items:center;justify-content:space-between}
.asst-h b{font-family:var(--display);font-size:1.1rem}
.asst-h small{display:block;color:var(--on-slate-2);font-size:.75rem}
.asst-h button{background:none;border:0;color:#fff;font-size:1.4rem;line-height:1;cursor:pointer;padding:4px 8px}
.asst-log{padding:14px;overflow-y:auto;flex:1;display:flex;flex-direction:column;gap:10px;font-size:.95rem}
.msg{padding:10px 12px;border-radius:8px;max-width:92%;line-height:1.45}
.msg.bot{background:var(--paper);border:1px solid var(--line);align-self:flex-start}
.msg.me{background:var(--air);color:#fff;align-self:flex-end}
.msg a{color:inherit}
.chips{display:flex;flex-wrap:wrap;gap:6px}
.chip{background:var(--white);border:1px solid var(--air);color:var(--air-2);font:inherit;font-size:.85rem;padding:6px 10px;border-radius:999px;cursor:pointer}
.chip:hover{background:var(--air);color:#fff}
.asst-in{display:flex;gap:8px;padding:10px;border-top:1px solid var(--line)}
.asst-in input{flex:1;font:inherit;padding:10px;border:1px solid var(--line);border-radius:var(--radius);background:var(--white);color:var(--ink)}
.asst-in button{font:inherit;font-weight:600;background:var(--slate);color:#fff;border:0;padding:10px 14px;border-radius:var(--radius);cursor:pointer}
.asst .mini{display:grid;gap:8px;grid-template-columns:1fr 1fr}
.asst .mini input,.asst .mini select{width:100%;font:inherit;padding:8px;border:1px solid var(--line);border-radius:var(--radius);background:var(--white);color:var(--ink)}
.asst .mini button{grid-column:1/-1;font:inherit;font-weight:600;background:var(--signal);color:#17222C;border:0;padding:9px;border-radius:var(--radius);cursor:pointer}
/* misc */
.pill{display:inline-block;background:var(--paper);border:1px solid var(--line);padding:2px 8px;border-radius:999px;font-size:.8rem;color:var(--ink-2)}
.sec-slate .pill{background:transparent;border-color:var(--on-slate-2);color:var(--on-slate)}
.notfound{text-align:left;padding:80px 0}
.notfound h1{font-size:clamp(3rem,10vw,6rem)}
hr.rule{border:0;border-top:1px solid var(--line);margin:32px 0}
.stat-row{display:flex;flex-wrap:wrap;gap:28px}
.stat-row div{min-width:140px}
.stat-row b{display:block;font-family:var(--display);font-size:1.7rem;font-weight:700;line-height:1.1}
.stat-row span{color:var(--ink-2);font-size:.9rem}