:root {
  --bg: #ffffff;
  --fg: #1a1f2b;
  --muted: #5b6472;
  --line: #e6e9ef;
  --brand: #1f7a5a;
  --brand-dark: #155c43;
  --card: #f7f9fb;
  --accent: #eef6f2;
  --radius: 12px;
  --maxw: 760px;
}
* { box-sizing: border-box; }
html { -webkit-text-size-adjust: 100%; }
body {
  margin: 0;
  font-family: system-ui, -apple-system, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
  color: var(--fg);
  background: var(--bg);
  line-height: 1.6;
}
.container { max-width: var(--maxw); margin: 0 auto; padding: 0 18px; }
main.container { padding-top: 8px; padding-bottom: 48px; }

.site-header { border-bottom: 1px solid var(--line); background: #fff; position: sticky; top: 0; z-index: 10; }
.header-inner { display: flex; align-items: center; height: 58px; }
.logo { font-weight: 700; font-size: 1.2rem; color: var(--brand-dark); text-decoration: none; letter-spacing: -0.3px; }

.hero { text-align: center; padding: 40px 0 24px; }
.hero h1 { font-size: 2rem; margin: 0 0 8px; letter-spacing: -0.5px; }
.hero p { color: var(--muted); font-size: 1.05rem; margin: 0; }

.cat-head { margin: 34px 0 14px; font-size: 1.25rem; border-bottom: 1px solid var(--line); padding-bottom: 8px; }
.grid { display: grid; grid-template-columns: repeat(auto-fill, minmax(220px, 1fr)); gap: 14px; }
.card { display: block; padding: 16px; background: var(--card); border: 1px solid var(--line); border-radius: var(--radius); text-decoration: none; color: inherit; transition: border-color .15s, transform .15s; }
.card:hover { border-color: var(--brand); transform: translateY(-2px); }
.card h3 { margin: 0 0 6px; font-size: 1.02rem; color: var(--brand-dark); }
.card p { margin: 0; color: var(--muted); font-size: .9rem; }

.crumbs { font-size: .85rem; color: var(--muted); padding: 14px 0 4px; }
.crumbs a { color: var(--brand-dark); text-decoration: none; }
article h1 { font-size: 1.7rem; letter-spacing: -0.4px; margin: 6px 0 10px; }
.lede { color: var(--muted); font-size: 1.05rem; margin-top: 0; }

.tool { background: var(--accent); border: 1px solid var(--line); border-radius: var(--radius); padding: 20px; margin: 20px 0; }
.field { margin-bottom: 14px; }
.field label { display: block; font-weight: 600; font-size: .92rem; margin-bottom: 5px; }
.field input, .field select {
  width: 100%; padding: 11px 12px; font-size: 1rem; border: 1px solid var(--line);
  border-radius: 9px; background: #fff; color: var(--fg);
}
.field input:focus, .field select:focus { outline: 2px solid var(--brand); border-color: var(--brand); }
.row { display: grid; grid-template-columns: 1fr 1fr; gap: 12px; }
button.calc-btn {
  width: 100%; padding: 13px; font-size: 1.02rem; font-weight: 700; color: #fff;
  background: var(--brand); border: 0; border-radius: 9px; cursor: pointer; margin-top: 4px;
}
button.calc-btn:hover { background: var(--brand-dark); }
.result { margin-top: 18px; padding: 16px; background: #fff; border: 1px solid var(--line); border-radius: 9px; display: none; }
.result.show { display: block; }
.result .big { font-size: 1.9rem; font-weight: 800; color: var(--brand-dark); letter-spacing: -0.5px; }
.result .sub { color: var(--muted); font-size: .92rem; margin-top: 4px; }
.result table { width: 100%; border-collapse: collapse; margin-top: 10px; font-size: .92rem; }
.result td { padding: 5px 0; border-bottom: 1px solid var(--line); }
.result td:last-child { text-align: right; font-weight: 600; }

.explainer { margin: 26px 0; }
.explainer h2 { font-size: 1.3rem; margin: 22px 0 8px; }
.explainer h3 { font-size: 1.08rem; margin: 18px 0 6px; }
.explainer p, .explainer li { color: #2b3240; }

.faqs { margin-top: 28px; }
.faqs h2 { font-size: 1.3rem; }
.faq { border: 1px solid var(--line); border-radius: 9px; padding: 4px 14px; margin-bottom: 10px; background: var(--card); }
.faq summary { cursor: pointer; font-weight: 600; padding: 8px 0; }
.faq p { margin: 4px 0 12px; color: var(--muted); }

.ad-slot { margin: 22px 0; min-height: 90px; display: flex; align-items: center; justify-content: center; background: repeating-linear-gradient(45deg,#fafbfc,#fafbfc 10px,#f2f4f7 10px,#f2f4f7 20px); border: 1px dashed var(--line); border-radius: 9px; color: #aab; font-size: .8rem; }

.site-footer { border-top: 1px solid var(--line); padding: 26px 0; color: var(--muted); font-size: .88rem; text-align: center; }
.site-footer nav a { color: var(--brand-dark); text-decoration: none; }
.site-footer .disclaimer { font-size: .8rem; margin-top: 8px; }

@media (max-width: 480px) {
  .row { grid-template-columns: 1fr; }
  .hero h1 { font-size: 1.6rem; }
}