:root{
  --bg:#f5f7fb; --card:#ffffff; --text:#172033; --muted:#64748b; --line:#dbe3ef;
  --accent:#1f6feb; --accent2:#0f4fb8; --good:#0b7a53; --warn:#9a6700; --radius:18px;
  --shadow:0 14px 36px rgba(15,23,42,.08);
}
*{box-sizing:border-box}
html{scroll-behavior:smooth}
body{margin:0;background:var(--bg);color:var(--text);font-family:Inter,ui-sans-serif,system-ui,-apple-system,"Segoe UI",Roboto,Arial,sans-serif;line-height:1.55}
a{color:var(--accent);text-decoration:none}a:hover{text-decoration:underline}
.container{width:min(1180px,calc(100% - 32px));margin:0 auto}
.site-header{position:sticky;top:0;z-index:40;background:rgba(255,255,255,.94);backdrop-filter:blur(12px);border-bottom:1px solid rgba(219,227,239,.9)}
.header-inner{display:flex;align-items:center;justify-content:space-between;min-height:68px;gap:24px}
.brand{display:flex;align-items:center;gap:10px;color:var(--text);font-weight:800;font-size:20px;white-space:nowrap}.brand:hover{text-decoration:none}
.brand-mark{width:34px;height:34px;border-radius:10px;background:linear-gradient(145deg,#1f6feb,#0f4fb8);display:grid;place-items:center;color:#fff;font-size:18px}
.nav{display:flex;gap:18px;align-items:center;font-size:14px}.nav a{color:#334155;font-weight:650}.nav a:hover{color:var(--accent);text-decoration:none}
.menu-toggle{display:none;border:1px solid var(--line);background:#fff;border-radius:10px;padding:8px 10px;font:inherit}
.hero{padding:58px 0 34px;background:radial-gradient(circle at 80% 10%,rgba(31,111,235,.12),transparent 34%),linear-gradient(#fff,#f8fbff)}
.hero-grid{display:grid;grid-template-columns:1.2fr .8fr;gap:38px;align-items:center}.eyebrow{font-size:13px;font-weight:800;text-transform:uppercase;letter-spacing:.08em;color:var(--accent)}
h1{font-size:clamp(32px,5vw,56px);line-height:1.05;margin:10px 0 18px;letter-spacing:-.035em}h2{font-size:clamp(24px,3vw,34px);line-height:1.18;margin:0 0 14px;letter-spacing:-.02em}h3{font-size:20px;line-height:1.25;margin:0 0 10px}.lead{font-size:19px;color:#475569;max-width:760px}.hero-actions{display:flex;gap:12px;flex-wrap:wrap;margin-top:24px}
.btn{display:inline-flex;align-items:center;justify-content:center;gap:8px;border:0;border-radius:12px;padding:12px 17px;font:inherit;font-weight:750;cursor:pointer;transition:.18s;background:var(--accent);color:#fff}.btn:hover{background:var(--accent2);text-decoration:none;transform:translateY(-1px)}.btn.secondary{background:#fff;color:var(--text);border:1px solid var(--line)}.btn.secondary:hover{background:#f8fafc}.btn.ghost{background:transparent;color:var(--accent);border:1px solid #b9d2fb}.btn.small{padding:9px 12px;font-size:14px}
.hero-visual{background:#0f172a;border-radius:24px;min-height:310px;box-shadow:var(--shadow);padding:26px;position:relative;overflow:hidden}.hero-visual svg{width:100%;height:auto}.hero-note{position:absolute;left:22px;bottom:20px;right:22px;color:#dbeafe;font-size:13px}
.section{padding:52px 0}.section.white{background:#fff}.section-head{max-width:800px;margin-bottom:24px}.section-head p{color:var(--muted);font-size:17px;margin:0}
.tool-grid,.guide-grid{display:grid;grid-template-columns:repeat(3,1fr);gap:18px}.tool-card,.guide-card{background:var(--card);border:1px solid var(--line);border-radius:var(--radius);padding:22px;box-shadow:0 8px 22px rgba(15,23,42,.04);color:inherit}.tool-card:hover,.guide-card:hover{border-color:#b6cef3;box-shadow:var(--shadow);text-decoration:none;transform:translateY(-2px)}.tool-card .icon{font-size:28px;margin-bottom:12px}.tool-card p,.guide-card p{color:var(--muted);margin:6px 0 0}.tool-card .tag{display:inline-flex;margin-top:14px;background:#eef5ff;color:#2459a9;border-radius:999px;padding:4px 9px;font-size:12px;font-weight:800}
.content-wrap{display:grid;grid-template-columns:minmax(0,1fr) 300px;gap:26px;align-items:start}.main-col{min-width:0}.sidebar{position:sticky;top:92px}.ad-slot{border:1px dashed #b8c4d6;border-radius:14px;background:#f8fafc;color:#94a3b8;display:grid;place-items:center;text-align:center;min-height:250px;padding:18px;font-size:12px}.ad-slot.horizontal{min-height:110px;margin:26px 0}.ad-label{font-size:11px;letter-spacing:.05em;text-transform:uppercase}
.breadcrumbs{font-size:13px;color:var(--muted);padding:18px 0}.breadcrumbs a{color:#51647f}.tool-page h1{font-size:clamp(32px,4vw,46px);margin-top:6px}.tool-intro{color:#475569;font-size:17px;max-width:850px}
.calc-card{background:#fff;border:1px solid var(--line);border-radius:22px;box-shadow:var(--shadow);overflow:hidden;margin:26px 0}.calc-head{padding:22px 24px;border-bottom:1px solid var(--line);display:flex;justify-content:space-between;gap:18px;align-items:flex-start}.calc-head p{margin:5px 0 0;color:var(--muted);font-size:14px}.calc-body{display:grid;grid-template-columns:360px minmax(0,1fr)}.calc-form{padding:22px;border-right:1px solid var(--line);background:#fbfdff}.field{margin-bottom:15px}.field label{display:block;font-size:13px;font-weight:800;margin-bottom:6px;color:#334155}.field-row{display:grid;grid-template-columns:1fr 84px;gap:8px}.field input,.field select{width:100%;border:1px solid #cbd5e1;border-radius:10px;background:#fff;padding:11px 12px;font:inherit;color:var(--text);outline:none}.field input:focus,.field select:focus{border-color:#78a7ef;box-shadow:0 0 0 3px rgba(31,111,235,.1)}.unit{display:grid;place-items:center;border:1px solid var(--line);border-radius:10px;background:#f8fafc;color:#64748b;font-size:13px}.hint{font-size:12px;color:#7a8799;margin-top:5px}.form-actions{display:flex;gap:9px;flex-wrap:wrap;margin-top:18px}.result-panel{padding:22px;min-width:0}.drawing-shell{border:1px solid var(--line);border-radius:14px;background:linear-gradient(#fff,#fafcff);min-height:330px;display:grid;place-items:center;overflow:auto;padding:14px;position:relative}.drawing-shell svg{max-width:100%;max-height:520px;width:auto;height:auto}.drawing-empty{color:#94a3b8;text-align:center;max-width:360px}.result-actions{display:flex;gap:9px;flex-wrap:wrap;margin-top:14px}.metrics{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:10px;margin-top:16px}.metric{border:1px solid var(--line);background:#fff;border-radius:12px;padding:12px}.metric b{display:block;font-size:16px}.metric span{display:block;color:var(--muted);font-size:12px;margin-top:2px}.calc-error{margin-top:12px;background:#fff3cd;color:#7a4d00;border:1px solid #ffe69c;border-radius:10px;padding:10px 12px;display:none}.calc-error.show{display:block}
.info-box{border:1px solid #cfe0fb;background:#f4f8ff;border-radius:14px;padding:16px 18px;margin:20px 0}.warning-box{border-color:#f4df9b;background:#fffaf0}.content-card{background:#fff;border:1px solid var(--line);border-radius:18px;padding:26px;margin:22px 0}.content-card p:last-child{margin-bottom:0}.content-card ul{padding-left:22px}.faq details{border-top:1px solid var(--line);padding:14px 0}.faq details:first-child{border-top:0}.faq summary{font-weight:800;cursor:pointer}.faq p{color:#556579;margin:9px 0 0}
.article{background:#fff;border:1px solid var(--line);border-radius:18px;padding:30px}.article h1{font-size:clamp(30px,4vw,44px)}.article h2{margin-top:34px}.article p,.article li{font-size:17px;color:#334155}.article .toc{background:#f8fafc;border:1px solid var(--line);border-radius:14px;padding:16px 18px;margin:24px 0}.article code{background:#eff4fa;border-radius:6px;padding:2px 5px;font-size:.92em}
.footer{background:#0f172a;color:#cbd5e1;padding:38px 0 28px;margin-top:46px}.footer-grid{display:grid;grid-template-columns:1.4fr 1fr 1fr;gap:28px}.footer a{color:#dbeafe}.footer h3{color:#fff;font-size:15px}.footer p,.footer li{font-size:13px;color:#9fb0c5}.footer ul{padding:0;list-style:none}.footer li{margin:7px 0}.footer-bottom{border-top:1px solid #263249;margin-top:28px;padding-top:18px;font-size:12px;color:#8291a8}
.kpi-strip{display:grid;grid-template-columns:repeat(4,1fr);gap:12px;margin-top:30px}.kpi{background:#fff;border:1px solid var(--line);border-radius:14px;padding:15px}.kpi b{display:block;font-size:22px}.kpi span{color:var(--muted);font-size:12px}
.sr-only{position:absolute;width:1px;height:1px;padding:0;margin:-1px;overflow:hidden;clip:rect(0,0,0,0);white-space:nowrap;border:0}
@media(max-width:960px){.hero-grid{grid-template-columns:1fr}.hero-visual{min-height:260px}.tool-grid,.guide-grid{grid-template-columns:repeat(2,1fr)}.content-wrap{grid-template-columns:1fr}.sidebar{position:static}.sidebar .ad-slot{min-height:110px}.calc-body{grid-template-columns:1fr}.calc-form{border-right:0;border-bottom:1px solid var(--line)}.metrics{grid-template-columns:repeat(2,1fr)}.footer-grid{grid-template-columns:1fr 1fr}.kpi-strip{grid-template-columns:repeat(2,1fr)}}
@media(max-width:680px){.container{width:min(100% - 20px,1180px)}.header-inner{min-height:60px}.nav{display:none;position:absolute;top:60px;left:10px;right:10px;background:#fff;border:1px solid var(--line);border-radius:14px;padding:12px;box-shadow:var(--shadow);flex-direction:column;align-items:flex-start}.nav.open{display:flex}.menu-toggle{display:block}.hero{padding:38px 0 26px}.hero-visual{min-height:220px}.tool-grid,.guide-grid{grid-template-columns:1fr}.section{padding:38px 0}.calc-head{padding:18px}.calc-form,.result-panel{padding:16px}.drawing-shell{min-height:260px}.metrics{grid-template-columns:1fr}.article{padding:20px}.footer-grid{grid-template-columns:1fr}.kpi-strip{grid-template-columns:1fr 1fr}.btn{width:100%}.result-actions .btn,.form-actions .btn{width:auto}.lead{font-size:17px}}
@media print{.site-header,.footer,.breadcrumbs,.sidebar,.ad-slot,.result-actions,.form-actions{display:none!important}body{background:#fff}.container{width:100%}.calc-card{box-shadow:none;border:0}.calc-body{display:block}.calc-form{display:none}.result-panel{padding:0}.drawing-shell{border:0;overflow:visible}}

/* ads are hidden until enabled */
.ad-slot{display:none}
.ad-slot.ad-active{display:grid}
.guides-more{margin-top:22px}
.guide-hub .guide-grid{margin-top:26px}
.not-found{margin-top:40px}
@media(max-width:680px){.guides-more .btn{width:auto}}