:root {
  --bg: #fafaf7;
  --surface: #ffffff;
  --text: #16181d;
  --muted: #5d6470;
  --line: #e4e4de;
  --accent: #0f9d6b;
  --accent-soft: #e2f5ec;
  --radius: 12px;
}
@media (prefers-color-scheme: dark) {
  :root {
    --bg: #111317;
    --surface: #181b21;
    --text: #eceef2;
    --muted: #a0a7b3;
    --line: #2a2e36;
    --accent: #34d399;
    --accent-soft: #15302a;
  }
}
* { box-sizing: border-box; }
html { -webkit-text-size-adjust: 100%; }
body {
  margin: 0;
  background: var(--bg);
  color: var(--text);
  font: 17px/1.65 -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
}
a { color: var(--accent); text-decoration: none; }
a:hover { text-decoration: underline; }
.wrap { max-width: 1080px; margin: 0 auto; padding: 0 16px; }

.site-header { background: var(--surface); border-bottom: 1px solid var(--line); position: sticky; top: 0; z-index: 10; }
.header-inner { display: flex; align-items: center; gap: 24px; min-height: 60px; }
.logo { font-weight: 800; font-size: 1.15rem; color: var(--text); white-space: nowrap; letter-spacing: -0.01em; }
.logo:hover { text-decoration: none; }
.bolt { margin-right: 4px; }
.nav { display: flex; gap: 18px; overflow-x: auto; scrollbar-width: none; }
.nav::-webkit-scrollbar { display: none; }
.nav a { color: var(--muted); font-size: 0.93rem; white-space: nowrap; font-weight: 500; }
.nav a:hover { color: var(--text); text-decoration: none; }

main { padding-top: 28px; padding-bottom: 48px; min-height: 60vh; }
h1, h2, h3 { line-height: 1.25; letter-spacing: -0.015em; }

.hero { padding: 28px 0 12px; max-width: 720px; }
.hero h1 { font-size: clamp(1.8rem, 4.5vw, 2.7rem); margin: 0 0 12px; }
.hero p { color: var(--muted); font-size: 1.1rem; margin: 0 0 16px; }
.btn { display: inline-block; background: var(--accent); color: #fff; padding: 10px 18px; border-radius: 999px; font-weight: 600; font-size: 0.95rem; }
@media (prefers-color-scheme: dark) { .btn { color: #07140f; } }
.btn:hover { text-decoration: none; opacity: 0.9; }

.section-title { font-size: 1.1rem; text-transform: uppercase; letter-spacing: 0.06em; color: var(--muted); margin: 32px 0 14px; }
.grid { display: grid; grid-template-columns: repeat(auto-fill, minmax(min(290px, 100%), 1fr)); gap: 16px; }
.card { background: var(--surface); border: 1px solid var(--line); border-radius: var(--radius); padding: 18px 20px; display: flex; flex-direction: column; gap: 6px; }
.card h3 { margin: 0; font-size: 1.12rem; }
.card h3 a { color: var(--text); }
.card p { margin: 0; color: var(--muted); font-size: 0.95rem; flex: 1; }
.card time { color: var(--muted); font-size: 0.82rem; }
.card-cat { font-size: 0.75rem; font-weight: 700; text-transform: uppercase; letter-spacing: 0.06em; align-self: flex-start; background: var(--accent-soft); padding: 2px 8px; border-radius: 999px; }
.more { margin-top: 20px; }

.post { max-width: 720px; margin: 0 auto; }
.post h1 { font-size: clamp(1.7rem, 4vw, 2.4rem); margin: 6px 0 8px; }
.crumbs, .meta { color: var(--muted); font-size: 0.9rem; margin: 0; }
.prose { margin-top: 24px; }
.prose h2 { font-size: 1.45rem; margin-top: 2em; }
.prose h3 { font-size: 1.15rem; margin-top: 1.6em; }
.prose img { max-width: 100%; height: auto; }
.prose table { width: 100%; border-collapse: collapse; font-size: 0.95rem; display: block; overflow-x: auto; }
.prose th, .prose td { border: 1px solid var(--line); padding: 8px 10px; text-align: left; }
.prose th { background: var(--accent-soft); }
.prose blockquote p { margin: 0; }
.prose blockquote { margin: 1.4em 0; padding: 12px 18px; border-left: 4px solid var(--accent); background: var(--surface); border-radius: 0 var(--radius) var(--radius) 0; }
.prose code { background: var(--accent-soft); padding: 1px 5px; border-radius: 4px; font-size: 0.9em; }
.related { max-width: 1080px; margin: 48px auto 0; }
.related h2 { font-size: 1.1rem; text-transform: uppercase; letter-spacing: 0.06em; color: var(--muted); }

.calc { background: var(--surface); border: 1px solid var(--line); border-radius: var(--radius); padding: 20px; display: grid; gap: 14px; }
.calc label { display: grid; gap: 4px; font-weight: 600; font-size: 0.95rem; }
.calc input, .calc select { font: inherit; padding: 9px 11px; border-radius: 8px; border: 1px solid var(--line); background: var(--bg); color: var(--text); }
.calc-result { background: var(--accent-soft); border-radius: var(--radius); padding: 16px; }
.calc-result strong { font-size: 1.5rem; display: block; }

.site-footer { border-top: 1px solid var(--line); background: var(--surface); color: var(--muted); font-size: 0.88rem; padding: 20px 0; }
.foot-links { display: flex; flex-wrap: wrap; gap: 16px; }
.foot-links a { color: var(--muted); }