:root {
  --bg: #ffffff;
  --bg-soft: #f6f8fb;
  --bg-card: #ffffff;
  --border: #e4e8ef;
  --text: #1a1f2b;
  --text-soft: #4a5468;
  --text-muted: #7a8394;
  --brand: #1a56db;
  --brand-dark: #1347b0;
  --accent: #0e7c6b;
  --accent-soft: #e8f0fe;
  --warn: #b45309;
  --warn-soft: #fff8e6;
  --shadow: 0 1px 2px rgba(16, 24, 40, 0.04), 0 1px 3px rgba(16, 24, 40, 0.08);
  --radius: 10px;
  --max-width: 900px;
  --font: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Oxygen, Ubuntu, Cantarell, "Helvetica Neue", Arial, sans-serif;
}

* { box-sizing: border-box; }

html, body { margin: 0; padding: 0; background: var(--bg); color: var(--text); font-family: var(--font); font-size: 17px; line-height: 1.6; -webkit-text-size-adjust: 100%; }

a { color: var(--brand); text-decoration: none; }
a:hover { text-decoration: underline; }

.container { max-width: var(--max-width); margin: 0 auto; padding: 0 20px; }

header.site-header { background: var(--bg); border-bottom: 1px solid var(--border); padding: 16px 0; }
.site-header .inner { max-width: var(--max-width); margin: 0 auto; padding: 0 20px; display: flex; align-items: center; justify-content: space-between; gap: 16px; }
.site-header .brand { font-weight: 700; font-size: 18px; color: var(--text); letter-spacing: -0.01em; }
.site-header nav a { font-size: 15px; color: var(--text-soft); margin-left: 18px; }

main { padding: 28px 0 60px; }

h1 { font-size: 34px; line-height: 1.2; margin: 0 0 10px; letter-spacing: -0.02em; }
h2 { font-size: 24px; line-height: 1.3; margin: 36px 0 12px; letter-spacing: -0.01em; }
h3 { font-size: 19px; line-height: 1.35; margin: 24px 0 8px; }

p { margin: 10px 0; color: var(--text-soft); }
ul, ol { color: var(--text-soft); }

.lede { font-size: 18px; color: var(--text-soft); margin: 0 0 22px; }

.trust { display: flex; align-items: center; gap: 10px; padding: 10px 14px; background: var(--bg-soft); border: 1px solid var(--border); border-radius: var(--radius); font-size: 14px; color: var(--text-soft); margin: 0 0 24px; }
.trust strong { color: var(--text); }

.calc { background: var(--bg-card); border: 1px solid var(--border); border-radius: var(--radius); padding: 24px; box-shadow: var(--shadow); margin: 20px 0 30px; }
.calc h2 { margin-top: 0; }

.calc .row { display: grid; grid-template-columns: 1fr 1fr; gap: 18px; margin-bottom: 6px; }

.calc .field { display: flex; flex-direction: column; margin-bottom: 14px; }
.calc label { font-size: 14px; font-weight: 600; color: var(--text); margin-bottom: 6px; }
.calc .hint { font-size: 12px; color: var(--text-muted); margin-top: 4px; }

.calc input[type="number"], .calc select { font: inherit; padding: 11px 12px; border: 1px solid var(--border); border-radius: 8px; background: #fff; color: var(--text); width: 100%; transition: border-color .15s, box-shadow .15s; }
.calc input[type="number"]:focus, .calc select:focus { border-color: var(--brand); box-shadow: 0 0 0 3px rgba(26, 86, 219, .12); outline: none; }

.result { margin-top: 22px; padding: 20px; border-radius: var(--radius); background: var(--accent-soft); border: 1px solid #c5d9f9; }
.result .big { font-size: 32px; font-weight: 700; color: #1a56db; margin: 0 0 4px; letter-spacing: -0.02em; }
.result .label { font-size: 13px; text-transform: uppercase; letter-spacing: 0.06em; color: #1a56db; font-weight: 700; }

.breakdown { margin-top: 16px; display: grid; grid-template-columns: 1fr 1fr; gap: 10px 18px; font-size: 15px; }
.breakdown div span { display: block; font-size: 12px; color: var(--text-muted); text-transform: uppercase; letter-spacing: 0.05em; margin-bottom: 2px; }
.breakdown div strong { color: var(--text); font-size: 17px; }

.disclaimer { margin-top: 18px; padding: 12px 14px; background: var(--warn-soft); border: 1px solid #f4d58f; border-radius: 8px; font-size: 13px; color: #6b4100; }

article h2 { border-top: 1px solid var(--border); padding-top: 28px; }
article h2:first-of-type { border-top: none; padding-top: 0; }

article p, article li { font-size: 17px; }
article ul, article ol { padding-left: 22px; }
article li { margin: 6px 0; }

.faq details { border: 1px solid var(--border); border-radius: 8px; padding: 12px 16px; margin: 10px 0; background: var(--bg-card); }
.faq summary { font-weight: 600; color: var(--text); cursor: pointer; list-style: none; }
.faq summary::-webkit-details-marker { display: none; }
.faq summary::before { content: "+ "; color: var(--brand); font-weight: 700; }
.faq details[open] summary::before { content: "\2212  "; }

.related { margin-top: 40px; padding-top: 28px; border-top: 1px solid var(--border); }
.related h2 { margin-top: 0; }
.related .grid { display: grid; grid-template-columns: 1fr 1fr; gap: 14px; }
.related a.card { display: block; padding: 16px 18px; border: 1px solid var(--border); border-radius: var(--radius); background: var(--bg-card); color: var(--text); text-decoration: none; transition: border-color .15s, transform .15s; }
.related a.card:hover { border-color: var(--brand); transform: translateY(-1px); text-decoration: none; }
.related a.card strong { display: block; margin-bottom: 4px; }
.related a.card span { font-size: 14px; color: var(--text-muted); }

footer.site-footer { margin-top: 60px; padding: 28px 0 40px; border-top: 1px solid var(--border); background: var(--bg-soft); font-size: 14px; color: var(--text-muted); }
.site-footer .inner { max-width: var(--max-width); margin: 0 auto; padding: 0 20px; }
.site-footer a { color: var(--text-soft); }
.site-footer p { margin: 6px 0; color: var(--text-muted); }

.hero { text-align: center; padding: 20px 0 10px; }
.hero h1 { font-size: 40px; }
.hero p { font-size: 19px; max-width: 620px; margin-left: auto; margin-right: auto; }

.calc-grid { display: grid; grid-template-columns: 1fr 1fr; gap: 16px; margin-top: 28px; }
.calc-grid a { display: block; padding: 20px 22px; border: 1px solid var(--border); border-radius: var(--radius); background: var(--bg-card); color: var(--text); text-decoration: none; box-shadow: var(--shadow); transition: border-color .15s, transform .15s; }
.calc-grid a:hover { border-color: var(--brand); transform: translateY(-1px); text-decoration: none; }
.calc-grid a strong { display: block; font-size: 18px; margin-bottom: 6px; letter-spacing: -0.01em; }
.calc-grid a span { font-size: 14px; color: var(--text-muted); }

@media (max-width: 640px) {
  h1 { font-size: 28px; }
  .hero h1 { font-size: 32px; }
  .calc .row { grid-template-columns: 1fr; gap: 0; }
  .breakdown { grid-template-columns: 1fr; }
  .related .grid, .calc-grid { grid-template-columns: 1fr; }
  .site-header nav a { margin-left: 12px; font-size: 14px; }
}