:root {
  --bg: #f6f8f7;
  --card: #ffffff;
  --ink: #16241d;
  --muted: #5c6b63;
  --line: #e3e9e5;
  --brand: #1f8a55;
  --brand-dark: #156b41;
  --accent: #fff7e6;
  --accent-line: #f0d9a8;
  --radius: 14px;
  --shadow: 0 1px 3px rgba(20, 40, 30, 0.06), 0 8px 24px rgba(20, 40, 30, 0.05);
  --maxw: 760px;
}

* { box-sizing: border-box; }
html { -webkit-text-size-adjust: 100%; }
body {
  margin: 0;
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
  color: var(--ink);
  background: var(--bg);
  line-height: 1.6;
  font-size: 17px;
}
a { color: var(--brand-dark); }
img { max-width: 100%; }

.wrap { max-width: var(--maxw); margin: 0 auto; padding: 0 18px; }

/* header / footer */
.site-header {
  background: var(--card);
  border-bottom: 1px solid var(--line);
}
.site-header .wrap {
  display: flex; align-items: center; justify-content: space-between;
  padding-top: 14px; padding-bottom: 14px;
}
.brand { display: inline-flex; align-items: center; gap: 9px; font-weight: 800; font-size: 1.25rem; color: var(--ink); text-decoration: none; letter-spacing: -0.02em; }
.brand .logo { width: 28px; height: 28px; display: block; }
.brand .brand-text span { color: var(--brand); }
.nav a { margin-left: 16px; text-decoration: none; color: var(--muted); font-weight: 600; font-size: 0.95rem; }
.nav a:hover { color: var(--brand-dark); }

.site-footer {
  margin-top: 56px; padding: 28px 0; border-top: 1px solid var(--line);
  color: var(--muted); font-size: 0.9rem; background: var(--card);
}
.site-footer a { color: var(--muted); }

/* hero / headings */
h1 { font-size: 2rem; line-height: 1.2; letter-spacing: -0.02em; margin: 28px 0 6px; }
.tagline { color: var(--muted); font-size: 1.1rem; margin: 0 0 8px; }
h2 { font-size: 1.4rem; margin: 32px 0 10px; letter-spacing: -0.01em; }
h3 { font-size: 1.1rem; margin: 22px 0 6px; }

/* calculator card */
.calc-card {
  background: var(--card); border: 1px solid var(--line); border-radius: var(--radius);
  box-shadow: var(--shadow); padding: 22px; margin: 18px 0 8px;
}
#calc-form { display: grid; grid-template-columns: 1fr 1fr; gap: 14px 18px; }
.field { display: flex; flex-direction: column; }
.field label { font-weight: 600; font-size: 0.92rem; margin-bottom: 5px; }
.field .unit { color: var(--muted); font-weight: 500; }
.field .control { display: flex; gap: 8px; }
.field input, .field select {
  width: 100%; padding: 11px 12px; font-size: 1rem; border: 1px solid var(--line);
  border-radius: 10px; background: #fff; color: var(--ink); -moz-appearance: textfield;
}
.field input:focus, .field select:focus { outline: 2px solid var(--brand); border-color: var(--brand); }
.field .unit-select { width: auto; flex: 0 0 auto; }
.field .help { color: var(--muted); font-size: 0.8rem; margin-top: 4px; }
.recalc {
  grid-column: 1 / -1; margin-top: 4px; padding: 12px 18px; font-size: 1.02rem; font-weight: 700;
  color: #fff; background: var(--brand); border: 0; border-radius: 10px; cursor: pointer;
}
.recalc:hover { background: var(--brand-dark); }

/* results */
#calc-results { margin-top: 18px; }
.result-empty { color: var(--muted); }
.result-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(150px, 1fr)); gap: 12px; }
.result {
  background: var(--bg); border: 1px solid var(--line); border-radius: 12px; padding: 14px 16px;
}
.result.emph { background: var(--accent); border-color: var(--accent-line); }
.rval { font-size: 1.7rem; font-weight: 800; letter-spacing: -0.02em; }
.rval .runit { font-size: 0.95rem; font-weight: 600; color: var(--muted); }
.rlabel { color: var(--muted); font-size: 0.9rem; margin-top: 2px; }
.rhint { color: var(--muted); font-size: 0.78rem; font-style: italic; }
.result.rtext .rval { font-size: 1.15rem; font-weight: 700; line-height: 1.3; }
.cost { margin-top: 14px; font-size: 1.05rem; }
.cost .costnote { color: var(--muted); font-size: 0.85rem; }

/* affiliate CTA */
.affiliate {
  display: inline-block; margin: 18px 0 6px; padding: 12px 20px; font-weight: 700;
  background: #ff9900; color: #1a1a1a; border-radius: 10px; text-decoration: none;
}
.affiliate:hover { background: #f08c00; }
.affiliate-note { color: var(--muted); font-size: 0.8rem; margin: 4px 0 0; }

/* prose content */
.prose p, .prose ul { color: var(--ink); }
.prose ul { padding-left: 20px; }
.prose li { margin: 4px 0; }

/* FAQ */
.faq details {
  background: var(--card); border: 1px solid var(--line); border-radius: 10px;
  padding: 4px 16px; margin: 8px 0;
}
.faq summary { cursor: pointer; font-weight: 600; padding: 10px 0; }
.faq details[open] summary { color: var(--brand-dark); }
.faq p { margin: 0 0 12px; color: var(--muted); }

/* related + home grid */
.card-grid { display: grid; grid-template-columns: repeat(auto-fill, minmax(220px, 1fr)); gap: 14px; margin: 14px 0; }
.tool-card {
  display: block; background: var(--card); border: 1px solid var(--line); border-radius: 12px;
  padding: 18px; text-decoration: none; color: var(--ink); box-shadow: var(--shadow);
  transition: transform 0.08s ease, border-color 0.08s ease;
}
.tool-card:hover { transform: translateY(-2px); border-color: var(--brand); }
.tool-card .t-title { font-weight: 700; font-size: 1.05rem; }
.tool-card .t-desc { color: var(--muted); font-size: 0.9rem; margin-top: 4px; }

/* ad slots */
.ad-slot { margin: 24px 0; min-height: 90px; display: flex; align-items: center; justify-content: center; }
.ad-placeholder {
  width: 100%; border: 1px dashed var(--line); border-radius: 10px; color: var(--muted);
  font-size: 0.8rem; text-align: center; padding: 28px 10px; background: var(--card);
}

.breadcrumb { color: var(--muted); font-size: 0.85rem; margin-top: 16px; }
.breadcrumb a { color: var(--muted); }

/* category sections (home) */
.count-line { color: var(--muted); margin: 0 0 18px; }
.cat-section { margin-top: 30px; }
.cat-section h2 { margin-bottom: 2px; }
.cat-blurb { color: var(--muted); margin: 0 0 12px; font-size: 0.95rem; }

/* share row */
.share { display: flex; align-items: center; flex-wrap: wrap; gap: 8px; margin: 16px 0 4px; }
.share-label { color: var(--muted); font-size: 0.9rem; font-weight: 600; }
.share-btn {
  font: inherit; font-size: 0.85rem; font-weight: 600; padding: 6px 12px; border-radius: 8px;
  border: 1px solid var(--line); background: var(--card); color: var(--ink); text-decoration: none; cursor: pointer;
}
.share-btn:hover { border-color: var(--brand); color: var(--brand-dark); }
.share-btn.copied { background: var(--brand); color: #fff; border-color: var(--brand); }

/* blog */
.post-date { color: var(--muted); font-size: 0.85rem; margin: 2px 0 0; }
.tool-card .post-date { margin-top: 8px; }
.prose article, .prose h2 { max-width: 100%; }
article.prose p, article.prose li { color: var(--ink); }
article.prose h2 { margin-top: 28px; }

@media (max-width: 560px) {
  body { font-size: 16px; }
  h1 { font-size: 1.6rem; }
  #calc-form { grid-template-columns: 1fr; }
  .nav a { margin-left: 12px; font-size: 0.9rem; }
}