:root { --primary: #1e6091; --bg: #f5f7fa; --text: #2c3e50; --muted: #6c757d; --border: #d1d9e0; --accent: #e67e22; --success: #27ae60; }
* { box-sizing: border-box; }
body { font-family: -apple-system, "Hiragino Sans", "Yu Gothic", sans-serif; background: var(--bg); color: var(--text); margin: 0; line-height: 1.85; }
.nav { background: white; border-bottom: 1px solid var(--border); padding: 12px 20px; }
.nav-inner { max-width: 900px; margin: 0 auto; display: flex; justify-content: space-between; align-items: center; }
.nav-logo { font-size: 18px; font-weight: 700; color: var(--primary); text-decoration: none; }
.nav a { color: var(--muted); text-decoration: none; font-size: 14px; margin-left: 14px; }
.nav a:hover { color: var(--primary); }
.breadcrumb { max-width: 860px; margin: 12px auto 0; padding: 0 20px; font-size: 12px; color: var(--muted); }
.breadcrumb a { color: var(--muted); }
article { max-width: 860px; margin: 16px auto; padding: 36px 28px; background: white; border-radius: 8px; box-shadow: 0 2px 8px rgba(0,0,0,0.06); }
h1 { font-size: 26px; color: var(--primary); border-bottom: 3px solid var(--primary); padding-bottom: 12px; margin-top: 0; line-height: 1.4; }
h2 { font-size: 20px; color: var(--primary); margin-top: 40px; border-left: 4px solid var(--primary); padding-left: 12px; }
h3 { font-size: 16px; color: var(--primary); margin-top: 24px; }
table { width: 100%; border-collapse: collapse; margin: 16px 0; font-size: 14px; }
th, td { border: 1px solid var(--border); padding: 10px 12px; text-align: left; vertical-align: top; }
th { background: #f8f9fa; color: var(--primary); font-weight: 600; }
td.num { text-align: right; font-family: monospace; }
ul, ol { padding-left: 22px; }
li { margin: 4px 0; }
a { color: var(--primary); }
.meta-info { font-size: 13px; color: var(--muted); margin-bottom: 24px; }
.lead { font-size: 16px; background: #f0f7fc; border-left: 4px solid var(--primary); padding: 14px 18px; border-radius: 4px; margin: 16px 0 28px; }
.note { background: #fef5e7; border-left: 3px solid var(--accent); padding: 12px 16px; border-radius: 4px; margin: 16px 0; font-size: 14px; }
.example { background: #ecf9f1; border-left: 3px solid var(--success); padding: 14px 18px; border-radius: 4px; margin: 16px 0; font-size: 14px; }
.toc { background: #fafbfc; border: 1px solid var(--border); border-radius: 8px; padding: 16px 22px; margin: 20px 0 32px; }
.toc h2 { margin-top: 0; font-size: 14px; border-left: none; padding-left: 0; color: var(--muted); }
.toc ol { margin: 8px 0 0; font-size: 14px; }
.toc a { text-decoration: none; }
.toc a:hover { text-decoration: underline; }
.formula { background: #fafbfc; border: 1px solid var(--border); padding: 14px; border-radius: 6px; font-family: monospace; font-size: 13px; line-height: 1.6; margin: 12px 0; }
.cta-tool { background: linear-gradient(135deg, #1e6091 0%, #2980b9 100%); color: white; padding: 20px 24px; border-radius: 8px; margin: 24px 0; text-align: center; }
.cta-tool h3 { color: white; margin: 0 0 8px; }
.cta-tool p { margin: 0 0 12px; opacity: 0.95; font-size: 14px; }
.cta-tool a { display: inline-block; background: white; color: var(--primary); padding: 8px 22px; border-radius: 4px; font-weight: 700; text-decoration: none; }
.faq details { background: #fafbfc; border: 1px solid var(--border); border-radius: 6px; padding: 12px 16px; margin-bottom: 8px; }
.faq summary { cursor: pointer; font-weight: 600; color: var(--primary); }
.faq p { margin: 8px 0 0; font-size: 14px; }
.sources { background: #fafbfc; border: 1px solid var(--border); border-radius: 6px; padding: 14px 18px; margin: 28px 0; font-size: 13px; }
.sources h3 { margin-top: 0; font-size: 14px; }
.related { background: white; padding: 24px; border-radius: 8px; max-width: 860px; margin: 16px auto; box-shadow: 0 2px 8px rgba(0,0,0,0.06); }
.related h2 { margin: 0 0 12px; font-size: 16px; color: var(--primary); }
.related li { font-size: 14px; margin: 6px 0; }
footer { text-align: center; padding: 24px; color: var(--muted); font-size: 13px; }
footer a { color: var(--muted); margin: 0 10px; }
@media (max-width: 600px) {
  article { padding: 24px 18px; margin: 10px; }
  h1 { font-size: 21px; }
  h2 { font-size: 17px; }
  table { font-size: 13px; }
  th, td { padding: 8px; }
}