/* StackCost base stylesheet - light, professional, ad-slot aware */
:root{
  --bg:#ffffff;
  --surface:#f8fafc;
  --surface-2:#f1f5f9;
  --border:#e2e8f0;
  --border-strong:#cbd5e1;
  --text:#0f172a;
  --text-2:#334155;
  --muted:#64748b;
  --brand:#2563eb;
  --brand-dark:#1d4ed8;
  --brand-soft:#eff6ff;
  --accent:#047857;
  --accent-soft:#ecfdf5;
  --warn:#b45309;
  --warn-soft:#fffbeb;
  --radius:10px;
  --radius-lg:14px;
  --shadow:0 1px 2px rgba(15,23,42,.06),0 4px 16px rgba(15,23,42,.05);
  --shadow-lg:0 2px 4px rgba(15,23,42,.06),0 12px 32px rgba(15,23,42,.10);
  --maxw:1120px;
  --sans:-apple-system,BlinkMacSystemFont,"Segoe UI",Roboto,"Helvetica Neue",Arial,sans-serif;
  --mono:ui-monospace,SFMono-Regular,Menlo,Consolas,monospace;
}
*{box-sizing:border-box}
html{-webkit-text-size-adjust:100%;scroll-behavior:smooth}
body{
  margin:0;background:var(--bg);color:var(--text);
  font-family:var(--sans);font-size:16px;line-height:1.65;
  -webkit-font-smoothing:antialiased;
}
img{max-width:100%;height:auto;display:block}
a{color:var(--brand);text-decoration:none}
a:hover{text-decoration:underline}
.wrap{max-width:var(--maxw);margin:0 auto;padding:0 20px}
.skip{position:absolute;left:-9999px}

/* ---------- header ---------- */
.site-header{
  position:sticky;top:0;z-index:40;background:rgba(255,255,255,.92);
  backdrop-filter:blur(8px);border-bottom:1px solid var(--border);
}
.site-header .wrap{display:flex;align-items:center;gap:28px;height:62px}
.brand{display:flex;align-items:center;gap:9px;font-weight:700;font-size:17px;color:var(--text);letter-spacing:-.01em}
.brand:hover{text-decoration:none}
.brand-mark{
  width:26px;height:26px;border-radius:7px;flex:none;
  background:linear-gradient(135deg,var(--brand),#7c3aed);
  display:grid;place-items:center;color:#fff;font-size:13px;font-weight:800;
}
.site-nav{display:flex;gap:22px;margin-left:auto;align-items:center}
.site-nav a{color:var(--text-2);font-size:14.5px;font-weight:500}
.site-nav a:hover{color:var(--brand);text-decoration:none}
@media(max-width:720px){.site-nav{display:none}}

/* ---------- hero ---------- */
.hero{padding:44px 0 8px}
.hero h1{font-size:clamp(28px,4vw,40px);line-height:1.18;margin:0 0 12px;letter-spacing:-.025em}
.hero .sub{font-size:17.5px;color:var(--muted);margin:0;max-width:760px}
.byline{font-size:13.5px;color:var(--muted);margin:16px 0 0}
.crumbs{font-size:13.5px;color:var(--muted);margin-bottom:18px}
.crumbs a{color:var(--muted)}
.crumbs span{margin:0 7px;opacity:.6}

/* ---------- layout ---------- */
.layout{display:grid;grid-template-columns:minmax(0,1fr) 320px;gap:40px;align-items:start;padding:28px 0 64px}
@media(max-width:960px){.layout{grid-template-columns:1fr;gap:28px}}

/* ---------- calculator ---------- */
.calc-card{
  background:var(--surface);border:1px solid var(--border);
  border-radius:var(--radius-lg);padding:24px;box-shadow:var(--shadow);
}
.calc-title{font-size:14px;font-weight:700;text-transform:uppercase;letter-spacing:.07em;color:var(--muted);margin:0 0 18px}
.field{margin-bottom:16px}
.field label{display:block;font-size:14.5px;font-weight:600;margin-bottom:6px}
.field .hint{display:block;font-size:13px;color:var(--muted);margin-top:5px;line-height:1.5}
.input-group{display:flex;align-items:stretch;border:1px solid var(--border-strong);border-radius:var(--radius);background:#fff;overflow:hidden;transition:border-color .15s,box-shadow .15s}
.input-group:focus-within{border-color:var(--brand);box-shadow:0 0 0 3px rgba(37,99,235,.12)}
.input-group .addon{
  display:grid;place-items:center;padding:0 12px;background:var(--surface-2);
  color:var(--muted);font-size:14px;font-weight:600;white-space:nowrap;
}
.input-group input{
  flex:1;min-width:0;border:0;outline:0;padding:11px 13px;font-size:15.5px;
  font-family:var(--sans);font-weight:600;color:var(--text);background:transparent;
}
.input-group input::-webkit-outer-spin-button,
.input-group input::-webkit-inner-spin-button{-webkit-appearance:none;margin:0}
.input-group input[type=number]{-moz-appearance:textfield}

/* ---------- results ---------- */
.results{margin-top:26px}
.result-primary{
  background:linear-gradient(160deg,var(--brand),var(--brand-dark));
  color:#fff;border-radius:var(--radius-lg);padding:22px 24px;box-shadow:var(--shadow-lg);
}
.result-primary .r-label{font-size:13.5px;font-weight:600;opacity:.85;margin:0 0 4px;text-transform:uppercase;letter-spacing:.06em}
.result-primary .r-value{font-size:clamp(30px,5vw,42px);font-weight:800;letter-spacing:-.03em;line-height:1.1;margin:0}
.result-primary .r-hint{font-size:13.5px;opacity:.82;margin:8px 0 0}
.result-grid{display:grid;grid-template-columns:repeat(auto-fit,minmax(190px,1fr));gap:12px;margin-top:12px}
.result-item{background:#fff;border:1px solid var(--border);border-radius:var(--radius);padding:14px 16px}
.result-item .r-label{font-size:12.5px;font-weight:600;color:var(--muted);text-transform:uppercase;letter-spacing:.05em;margin:0 0 5px}
.result-item .r-value{font-size:22px;font-weight:750;letter-spacing:-.02em;color:var(--text);margin:0}
.result-item .r-hint{font-size:12.5px;color:var(--muted);margin:6px 0 0;line-height:1.45}
.disclaimer{font-size:12.5px;color:var(--muted);margin-top:16px;line-height:1.55}

/* ---------- prose ---------- */
.prose{margin-top:40px}
.prose h2{font-size:23px;letter-spacing:-.02em;margin:36px 0 12px;padding-top:6px}
.prose h3{font-size:18px;margin:26px 0 8px}
.prose p{margin:0 0 14px;color:var(--text-2)}
.prose ul,.prose ol{color:var(--text-2);padding-left:22px;margin:0 0 16px}
.prose li{margin-bottom:7px}
.steps{counter-reset:s;list-style:none;padding:0;margin:0 0 16px}
.steps li{counter-increment:s;position:relative;padding-left:40px;margin-bottom:14px;color:var(--text-2)}
.steps li::before{
  content:counter(s);position:absolute;left:0;top:1px;width:26px;height:26px;border-radius:50%;
  background:var(--brand-soft);color:var(--brand);display:grid;place-items:center;
  font-size:13px;font-weight:700;
}

/* ---------- faq ---------- */
.faq{margin-top:12px}
.faq details{border:1px solid var(--border);border-radius:var(--radius);padding:0;margin-bottom:10px;background:#fff;overflow:hidden}
.faq details[open]{border-color:var(--border-strong);box-shadow:var(--shadow)}
.faq summary{
  cursor:pointer;padding:15px 18px;font-weight:650;font-size:15.5px;
  list-style:none;display:flex;justify-content:space-between;gap:14px;align-items:flex-start;
}
.faq summary::-webkit-details-marker{display:none}
.faq summary::after{content:"+";color:var(--muted);font-weight:400;font-size:19px;line-height:1;flex:none}
.faq details[open] summary::after{content:"\2212"}
.faq .a{padding:0 18px 16px;color:var(--text-2);font-size:15px;line-height:1.68}

/* ---------- cta ---------- */
.cta{
  border:1px solid var(--border);border-left:4px solid var(--accent);
  background:var(--accent-soft);border-radius:var(--radius);
  padding:20px 22px;margin:28px 0;
}
.cta h3{margin:0 0 8px;font-size:17.5px;letter-spacing:-.01em}
.cta p{margin:0 0 14px;color:var(--text-2);font-size:15px}
.btn{
  display:inline-block;background:var(--accent);color:#fff;font-weight:650;
  padding:11px 20px;border-radius:var(--radius);font-size:15px;
}
.btn:hover{background:#065f46;text-decoration:none;color:#fff}
.btn-brand{background:var(--brand)}
.btn-brand:hover{background:var(--brand-dark)}
.disclosure{font-size:12px;color:var(--muted);margin-top:10px}

/* ---------- sidebar ---------- */
.sidebar{position:sticky;top:82px}
.side-card{background:var(--surface);border:1px solid var(--border);border-radius:var(--radius-lg);padding:18px 20px;margin-bottom:18px}
.side-card h4{margin:0 0 12px;font-size:13px;font-weight:700;text-transform:uppercase;letter-spacing:.07em;color:var(--muted)}
.side-card ul{list-style:none;margin:0;padding:0}
.side-card li{margin-bottom:9px;font-size:14.5px;line-height:1.5}
.side-card li a{font-weight:550}
.toc a{color:var(--text-2);font-weight:500}
.ad-slot{
  min-height:250px;border:1px dashed var(--border-strong);border-radius:var(--radius);
  display:grid;place-items:center;color:var(--muted);font-size:12.5px;
  background:var(--surface-2);text-align:center;padding:16px;
}

/* ---------- index / cards ---------- */
.grid-cards{display:grid;grid-template-columns:repeat(auto-fill,minmax(280px,1fr));gap:16px;margin:24px 0}
.card{background:#fff;border:1px solid var(--border);border-radius:var(--radius-lg);padding:20px;transition:box-shadow .16s,border-color .16s,transform .16s}
.card:hover{box-shadow:var(--shadow-lg);border-color:var(--border-strong);transform:translateY(-1px)}
.card h3{margin:0 0 8px;font-size:17px;letter-spacing:-.015em}
.card p{margin:0;color:var(--muted);font-size:14.5px}
.tag{display:inline-block;font-size:11.5px;font-weight:700;text-transform:uppercase;letter-spacing:.06em;color:var(--brand);background:var(--brand-soft);padding:3px 9px;border-radius:20px;margin-bottom:10px}
.tag-draft{color:var(--warn);background:var(--warn-soft)}

/* ---------- footer ---------- */
.site-footer{border-top:1px solid var(--border);background:var(--surface);margin-top:40px;padding:36px 0 44px}
.site-footer .cols{display:grid;grid-template-columns:2fr 1fr 1fr;gap:32px}
@media(max-width:720px){.site-footer .cols{grid-template-columns:1fr;gap:22px}}
.site-footer h5{margin:0 0 10px;font-size:13px;text-transform:uppercase;letter-spacing:.07em;color:var(--muted)}
.site-footer ul{list-style:none;margin:0;padding:0}
.site-footer li{margin-bottom:7px;font-size:14.5px}
.site-footer .note{font-size:13px;color:var(--muted);margin-top:24px;padding-top:20px;border-top:1px solid var(--border);line-height:1.6}