/* BuildCalc — single shared stylesheet. No framework, no web fonts (speed + privacy). */
:root{
  --ink:#1c1917; --ink-2:#44403c; --muted:#78716c;
  --line:#e7e5e4; --line-2:#d6d3d1;
  --bg:#faf9f7; --card:#ffffff;
  --accent:#c2410c; --accent-dark:#9a3412; --accent-soft:#fff7ed;
  --ok:#15803d;
  --radius:14px;
  --shadow:0 1px 2px rgba(28,25,23,.05), 0 8px 24px -12px rgba(28,25,23,.18);
  --wrap:1080px;
}
*{box-sizing:border-box}
html{-webkit-text-size-adjust:100%;scroll-behavior:smooth}
body{
  margin:0;background:var(--bg);color:var(--ink);
  font:16px/1.65 ui-sans-serif,system-ui,-apple-system,"Segoe UI",Roboto,"Helvetica Neue",Arial,"Noto Sans",sans-serif;
  -webkit-font-smoothing:antialiased;
}
img{max-width:100%;height:auto}
a{color:var(--accent-dark);text-decoration-thickness:1px;text-underline-offset:2px}
a:hover{color:var(--accent)}
.wrap{max-width:var(--wrap);margin:0 auto;padding:0 20px}

/* ---------- header ---------- */
.site-header{position:sticky;top:0;z-index:20;background:rgba(250,249,247,.92);backdrop-filter:saturate(140%) blur(8px);border-bottom:1px solid var(--line)}
.site-header .wrap{display:flex;align-items:center;gap:24px;height:62px}
.logo{display:flex;align-items:center;gap:9px;font-weight:800;font-size:18px;letter-spacing:-.02em;color:var(--ink)}
.logo:hover{color:var(--ink);text-decoration:none}
.logo-mark{width:26px;height:26px;border-radius:7px;background:var(--accent);color:#fff;display:grid;place-items:center;font-size:14px;font-weight:800;flex:none}
.nav{display:flex;gap:22px;margin-left:auto;align-items:center}
.nav a{color:var(--ink-2);font-size:14.5px;font-weight:550;text-decoration:none}
.nav a:hover{color:var(--accent-dark)}
@media(max-width:640px){.nav{gap:14px}.nav a.hide-sm{display:none}}

/* ---------- hero ---------- */
.hero{padding:56px 0 40px;border-bottom:1px solid var(--line);background:
  radial-gradient(900px 320px at 12% -10%, #fff1e6 0%, transparent 70%), var(--bg)}
.hero h1{font-size:clamp(30px,5vw,46px);line-height:1.12;letter-spacing:-.03em;margin:0 0 16px;font-weight:820}
.hero p.lede{font-size:clamp(16px,2.2vw,19px);color:var(--ink-2);max-width:640px;margin:0 0 26px}
.eyebrow{display:inline-block;font-size:12.5px;font-weight:700;letter-spacing:.09em;text-transform:uppercase;color:var(--accent-dark);background:var(--accent-soft);border:1px solid #fed7aa;padding:4px 10px;border-radius:999px;margin-bottom:18px}
.hero-actions{display:flex;flex-wrap:wrap;gap:12px}
.btn{display:inline-flex;align-items:center;gap:8px;padding:11px 18px;border-radius:10px;font-weight:650;font-size:15px;text-decoration:none;border:1px solid transparent;cursor:pointer}
.btn-primary{background:var(--accent);color:#fff;box-shadow:0 2px 0 #7c2d12}
.btn-primary:hover{background:var(--accent-dark);color:#fff}
.btn-ghost{background:#fff;border-color:var(--line-2);color:var(--ink)}
.btn-ghost:hover{border-color:var(--muted);color:var(--ink);text-decoration:none}

/* ---------- sections ---------- */
section{padding:44px 0}
section.tight{padding:28px 0}
h2{font-size:clamp(22px,3vw,28px);letter-spacing:-.02em;margin:0 0 10px;line-height:1.25}
h3{font-size:18px;letter-spacing:-.01em;margin:26px 0 8px}
.sub{color:var(--muted);margin:0 0 24px;max-width:700px}

/* ---------- cards / grids ---------- */
.grid{display:grid;gap:16px}
.grid-3{grid-template-columns:repeat(3,1fr)}
.grid-2{grid-template-columns:repeat(2,1fr)}
@media(max-width:900px){.grid-3{grid-template-columns:repeat(2,1fr)}}
@media(max-width:620px){.grid-3,.grid-2{grid-template-columns:1fr}}

.card{background:var(--card);border:1px solid var(--line);border-radius:var(--radius);padding:22px;box-shadow:var(--shadow);display:flex;flex-direction:column}
.card h3{margin:0 0 6px;font-size:17px}
.card p{margin:0;color:var(--ink-2);font-size:14.5px}
.card .unit-tag{margin-top:14px;font-size:12.5px;font-weight:650;color:var(--accent-dark);text-transform:uppercase;letter-spacing:.06em}
a.card{text-decoration:none;color:inherit;transition:border-color .15s, transform .15s}
a.card:hover{border-color:var(--accent);transform:translateY(-2px);color:inherit}

/* ---------- calculator ---------- */
.calc{background:var(--card);border:1px solid var(--line);border-radius:var(--radius);box-shadow:var(--shadow);padding:24px;margin:26px 0 8px}
.calc-grid{display:grid;grid-template-columns:repeat(3,1fr);gap:14px 16px}
@media(max-width:760px){.calc-grid{grid-template-columns:repeat(2,1fr)}}
@media(max-width:460px){.calc-grid{grid-template-columns:1fr}}
.field{display:flex;flex-direction:column;gap:6px;font-size:13.5px;font-weight:600;color:var(--ink-2)}
.field-box{display:flex;align-items:stretch;border:1px solid var(--line-2);border-radius:10px;background:#fff;overflow:hidden}
.field-box:focus-within{border-color:var(--accent);box-shadow:0 0 0 3px #ffedd5}
.field-box input,.field-box select{
  border:0;outline:0;background:transparent;padding:10px 10px;font:inherit;font-weight:600;color:var(--ink);
  width:100%;min-width:0;appearance:none;-webkit-appearance:none
}
.field-box select{cursor:pointer;padding-right:26px;background-image:linear-gradient(45deg,transparent 50%,var(--muted) 50%),linear-gradient(135deg,var(--muted) 50%,transparent 50%);background-position:calc(100% - 15px) 50%,calc(100% - 10px) 50%;background-size:5px 5px,5px 5px;background-repeat:no-repeat}
.field-box .unit{padding:10px 11px;background:#f5f5f4;color:var(--muted);font-size:12.5px;font-weight:650;display:flex;align-items:center;white-space:nowrap;border-left:1px solid var(--line)}

.result{margin-top:22px;padding:18px 20px;border-radius:12px;background:linear-gradient(180deg,#fffdf8,#fff7ed);border:1px solid #fed7aa}
.result-head{display:flex;align-items:baseline;gap:10px;flex-wrap:wrap}
.result-label{font-size:13px;font-weight:700;letter-spacing:.06em;text-transform:uppercase;color:var(--accent-dark)}
.result-value{font-size:clamp(30px,6vw,42px);font-weight:840;letter-spacing:-.03em;line-height:1.1;color:var(--ink)}
.result-unit{font-size:15px;font-weight:650;color:var(--ink-2)}
.result-rows{margin-top:14px;border-top:1px dashed #fdba74;padding-top:12px;display:grid;gap:6px}
.result-row{display:flex;justify-content:space-between;gap:16px;font-size:14.5px;color:var(--ink-2)}
.result-row b{font-variant-numeric:tabular-nums;color:var(--ink)}
.result-note{margin-top:12px;font-size:13px;color:var(--muted);line-height:1.5}
.error{color:#b91c1c;font-weight:600}

/* ---------- content ---------- */
.prose{max-width:760px}
.prose p{margin:0 0 15px;color:var(--ink-2)}
.prose ul,.prose ol{margin:0 0 16px;padding-left:22px;color:var(--ink-2)}
.prose li{margin:0 0 7px}
.prose strong{color:var(--ink)}
.callout{border-left:3px solid var(--accent);background:#fff;border-radius:0 10px 10px 0;padding:14px 18px;margin:20px 0;box-shadow:var(--shadow);font-size:14.5px;color:var(--ink-2)}
.callout b{color:var(--ink)}

table{width:100%;border-collapse:collapse;margin:18px 0;font-size:14.5px;background:#fff;border-radius:10px;overflow:hidden;box-shadow:var(--shadow)}
th,td{text-align:left;padding:10px 12px;border-bottom:1px solid var(--line)}
th{background:#f5f5f4;font-size:12.5px;text-transform:uppercase;letter-spacing:.05em;color:var(--ink-2);font-weight:700}
tbody tr:last-child td{border-bottom:0}

details{border:1px solid var(--line);background:#fff;border-radius:11px;padding:0 16px;margin:0 0 10px;box-shadow:var(--shadow)}
details[open]{padding-bottom:8px}
summary{cursor:pointer;font-weight:650;padding:14px 0;font-size:15.5px;list-style:none;display:flex;justify-content:space-between;gap:14px;align-items:center}
summary::-webkit-details-marker{display:none}
summary::after{content:"+";color:var(--accent);font-weight:800;font-size:19px;line-height:1}
details[open] summary::after{content:"–"}
details p{margin:0 0 12px;color:var(--ink-2);font-size:14.8px}

.breadcrumb{font-size:13px;color:var(--muted);padding:18px 0 0}
.breadcrumb a{color:var(--muted);text-decoration:none}
.breadcrumb a:hover{color:var(--accent-dark);text-decoration:underline}

.page-head{padding:8px 0 4px}
.page-head h1{font-size:clamp(28px,4.4vw,40px);line-height:1.15;letter-spacing:-.028em;margin:10px 0 12px;font-weight:820}
.page-head .lede{font-size:17px;color:var(--ink-2);max-width:700px;margin:0}

/* ---------- ad placeholder ---------- */
.ad-slot{margin:26px 0;min-height:90px;border:1px dashed var(--line-2);border-radius:12px;display:grid;place-items:center;color:#a8a29e;font-size:12px;letter-spacing:.08em;text-transform:uppercase;background:#fff}
.ad-slot::after{content:"Advertisement"}

/* ---------- footer ---------- */
.site-footer{border-top:1px solid var(--line);background:#fff;margin-top:40px;padding:40px 0 30px}
.footer-grid{display:grid;grid-template-columns:1.6fr 1fr 1fr;gap:32px}
@media(max-width:760px){.footer-grid{grid-template-columns:1fr 1fr}}
.footer-grid h4{font-size:12.5px;text-transform:uppercase;letter-spacing:.08em;color:var(--muted);margin:0 0 12px}
.footer-grid ul{list-style:none;margin:0;padding:0;display:grid;gap:8px}
.footer-grid a{color:var(--ink-2);text-decoration:none;font-size:14px}
.footer-grid a:hover{color:var(--accent-dark);text-decoration:underline}
.footer-bottom{margin-top:30px;padding-top:18px;border-top:1px solid var(--line);font-size:12.5px;color:var(--muted);display:flex;justify-content:space-between;gap:16px;flex-wrap:wrap}
.footer-bottom a{color:var(--muted)}

/* ---------- misc ---------- */
.pill{display:inline-block;font-size:12px;font-weight:650;background:#f5f5f4;border:1px solid var(--line);color:var(--ink-2);padding:3px 9px;border-radius:999px;margin:0 6px 6px 0}
.related{display:flex;flex-wrap:wrap;gap:10px;margin:16px 0 0}
.related a{font-size:14px;font-weight:600;background:#fff;border:1px solid var(--line-2);border-radius:999px;padding:7px 14px;text-decoration:none;color:var(--ink-2)}
.related a:hover{border-color:var(--accent);color:var(--accent-dark);text-decoration:none}
.skip{position:absolute;left:-9999px}
.skip:focus{left:10px;top:10px;background:#fff;padding:10px;border-radius:8px;z-index:99}