/* ventsystem shared re-skin (screenshot-matched design system) */
:root{
  --bg:#ffffff; --bg-alt:#f7f8f7; --text:#1e1e1e; --text-mute:#5b625b;
  --accent:#4e6841; --accent-dark:#3a4d30; --accent-tint:#e7ede0;
  --border:#e7e7e5; --footer-bg:#24272c; --footer-text:#c9cdc7;
}
*{box-sizing:border-box}
html{-webkit-text-size-adjust:100%}
body{
  margin:0; background:var(--bg); color:var(--text);
  font-family:-apple-system,"Apple SD Gothic Neo","Malgun Gothic","Noto Sans KR",sans-serif;
  line-height:1.7; font-size:clamp(15px,3.9vw,17px);
}
a{color:inherit}
img{max-width:100%; display:block}
:focus-visible{outline:2px solid var(--accent); outline-offset:2px}
h1{font-size:clamp(26px,6.2vw,52px); line-height:1.25; margin:6px 0 14px}
h2{font-size:clamp(20px,3.4vw,28px); margin:32px 0 12px}
h3{font-size:clamp(16px,2.6vw,19px); margin:0 0 8px}
p{margin:0 0 14px; max-width:70ch}

/* header */
.site-head{
  display:flex; align-items:center; gap:20px; padding:12px max(16px,env(safe-area-inset-left)) 12px max(16px,env(safe-area-inset-right));
  border-bottom:1px solid var(--border); background:var(--bg); position:sticky; top:0; z-index:20;
}
.brand{display:flex; align-items:center; gap:8px; font-weight:800; text-decoration:none; color:var(--accent-dark); letter-spacing:.02em; white-space:nowrap}
.brand-mark{color:var(--accent); flex:0 0 auto}
.site-nav{display:flex; gap:18px; margin:0 auto; flex-wrap:wrap}
.site-nav a{text-decoration:none; color:var(--text-mute); font-size:14px; padding:8px 2px}
.site-nav a:hover{color:var(--accent-dark)}
.btn-consult{
  background:var(--accent); color:#fff; text-decoration:none; font-weight:700; font-size:14px;
  padding:10px 20px; border-radius:999px; min-height:44px; display:inline-flex; align-items:center; white-space:nowrap;
}
@media (max-width:760px){ .site-nav{display:none} }

/* hero */
.hero{background:var(--bg-alt); padding:36px max(16px,env(safe-area-inset-left)) 30px; }
.crumb{font-size:13px; color:var(--text-mute); margin:0 0 10px}
.crumb a{text-decoration:none; color:var(--text-mute)}
.crumb a:hover{color:var(--accent-dark)}
.crumb span{margin:0 6px}
.eyebrow{font-size:12px; font-weight:700; letter-spacing:.14em; color:var(--accent); margin:0 0 6px; text-transform:uppercase}
.lead{color:var(--text-mute); max-width:76ch}

/* layout / toc (ventfacility) */
.layout{display:grid; grid-template-columns:220px 1fr; gap:32px; padding:28px max(16px,env(safe-area-inset-left))}
.toc{display:flex; flex-direction:column; gap:10px; align-self:start; position:sticky; top:74px}
.toc a{text-decoration:none; color:var(--text-mute); font-size:14px; border-left:2px solid var(--border); padding-left:12px}
.toc a:hover{color:var(--accent-dark); border-color:var(--accent)}
@media (max-width:760px){ .layout{grid-template-columns:1fr} .toc{position:static; flex-direction:row; flex-wrap:wrap} }

.body-copy{padding:0;display:flex;flex-direction:column;gap:20px}
main > .body-copy{padding:28px max(16px,env(safe-area-inset-left))}
.content-block{background:var(--bg-alt);border:1px solid var(--border);border-radius:12px;padding:22px 24px}
.content-block h2{margin-top:0}
.term-box{background:var(--bg-alt); border-left:4px solid var(--accent); padding:14px 16px; border-radius:8px; margin:14px 0}
.term-box h3{color:var(--accent-dark)}

table{width:100%; border-collapse:collapse; margin:16px 0; font-size:14px}
caption{text-align:left; color:var(--text-mute); font-size:13px; margin-bottom:8px}
th,td{padding:10px 12px; border-bottom:1px solid var(--border); text-align:left}
thead th{background:var(--accent-tint); color:var(--accent-dark); font-weight:700}
table:not(:has(thead)){ } /* no-op fallback */
@media (max-width:640px){ .body-copy table, main table{display:block; overflow-x:auto; white-space:nowrap} }

/* scrollzone / diagram (exhaustsystem) */
.scrollzone{overflow-x:auto; -webkit-overflow-scrolling:touch; padding:20px max(16px,env(safe-area-inset-left)); background:var(--bg-alt)}
.scrollzone-inner{display:flex; gap:16px}
.diagram-card{flex:0 0 190px; background:#fff; border:1px solid var(--border); border-radius:12px; padding:16px; text-align:center}
.duct-shape{width:100%; height:70px; background:var(--accent-tint); border-radius:8px; margin-bottom:10px}
.duct-shape.narrow{height:40px}
.duct-shape.wide{height:100px}

/* compare (airsupply) */
.compare{display:grid; grid-template-columns:1fr 1fr; gap:16px; padding:0 max(16px,env(safe-area-inset-left))}
.compare-col{background:var(--bg-alt); border-radius:12px; padding:16px}
@media (max-width:640px){ .compare{grid-template-columns:1fr} }

/* steps (ventduct) */
.steps{list-style:none; padding:0 max(16px,env(safe-area-inset-left)); counter-reset:step; margin:16px 0}
.steps li{counter-increment:step; position:relative; padding:0 0 16px 44px; margin-bottom:4px}
.steps li::before{
  content:counter(step); position:absolute; left:0; top:-2px; width:28px; height:28px; border-radius:50%;
  background:var(--accent); color:#fff; display:flex; align-items:center; justify-content:center; font-size:13px; font-weight:700;
}

/* before/after (ventreplace) */
.before-after{display:grid; grid-template-columns:1fr 1fr; gap:16px}
.ba-col{padding:16px; border-radius:12px}
.ba-before{background:#fbeee9}
.ba-after{background:var(--accent-tint)}
@media (max-width:640px){ .before-after{grid-template-columns:1fr} }

/* checklist (ventconstruct) */
.checklist{list-style:none; padding:0 max(16px,env(safe-area-inset-left)); margin:16px 0}
.checklist li{position:relative; padding-left:28px; margin-bottom:10px}
.checklist li::before{content:""; position:absolute; left:0; top:5px; width:14px; height:14px; border:2px solid var(--accent); border-radius:4px}
.num{font-weight:800; color:var(--accent); font-size:13px; letter-spacing:.06em}

/* photo grid */
.grid{display:grid; grid-template-columns:repeat(2,1fr); gap:12px; padding:24px max(16px,env(safe-area-inset-left))}
@media (min-width:768px){ .grid{grid-template-columns:repeat(4,1fr)} }
.shot{margin:0; border-radius:12px; overflow:hidden; border:1px solid var(--border)}
.shot img{aspect-ratio:4/3; object-fit:cover; object-position:center 35%; width:100%; height:auto}

/* related links */
.related-links{padding:8px max(16px,env(safe-area-inset-left)) 24px}
.related-links ul{list-style:none; padding:0; margin:10px 0 0; display:flex; flex-wrap:wrap; gap:10px}
.related-links li a{
  display:inline-flex; align-items:center; gap:6px; text-decoration:none; color:var(--accent-dark);
  background:var(--bg-alt); border:1px solid var(--border); border-radius:999px; padding:8px 16px; font-size:14px;
}
.related-links li a::after{content:"\2192"; font-size:13px}
.related-links li a:hover{background:var(--accent-tint)}

/* faq accordion */
.faq{padding:8px max(16px,env(safe-area-inset-left)) 8px}
.faq details{border-bottom:1px solid var(--border); padding:14px 0}
.faq summary{cursor:pointer; font-weight:700; list-style:none; display:flex; justify-content:space-between; gap:12px}
.faq summary::-webkit-details-marker{display:none}
.faq summary::after{content:"+"; color:var(--accent); font-size:20px; font-weight:400}
.faq details[open] summary::after{content:"\2212"}
.faq p{margin-top:10px; color:var(--text-mute)}

/* cta banner */
.cta{
  display:flex; flex-wrap:wrap; gap:12px; align-items:center; justify-content:center;
  background:linear-gradient(120deg, var(--accent-dark), var(--accent));
  padding:32px max(16px,env(safe-area-inset-left)); margin-top:16px;
}
.btn-call,.btn-sms{
  min-height:52px; border-radius:999px; padding:0 26px; display:inline-flex; align-items:center; justify-content:center;
  text-decoration:none; font-weight:700; font-size:15px;
}
.btn-call{background:#fff; color:var(--accent-dark)}
.btn-sms{background:transparent; color:#fff; border:1px solid rgba(255,255,255,.7)}

/* footer */
.site-foot{background:var(--footer-bg); color:var(--footer-text)}
.foot-row{display:flex; flex-wrap:wrap; gap:0 18px; font-size:12px; line-height:1.5; padding:14px max(20px,env(safe-area-inset-left))}
.foot-row span{padding-left:18px; border-left:1px solid rgba(255,255,255,.15)}
.foot-row span:first-child{padding-left:0; border-left:none}
.lastmod{margin:0; padding:0 20px 14px; font-size:11px; color:var(--footer-text); opacity:.8}

@media (prefers-reduced-motion: reduce){ *{transition:none !important; animation:none !important} }