:root {
  --bg: #0f1115;
  --card: #181b22;
  --line: #2a2f3a;
  --text: #eef0f4;
  --muted: #9aa1ad;
  --accent: #3ddc84;
  --accent-ink: #06210f;
  --warn: #ffb020;
  color-scheme: dark;
  font-family: system-ui, -apple-system, 'Segoe UI', Roboto, sans-serif;
}
@media (prefers-color-scheme: light) {
  :root {
    --bg: #f3f4f7;
    --card: #ffffff;
    --line: #dfe2e8;
    --text: #14171c;
    --muted: #616875;
    --accent: #12a150;
    --accent-ink: #ffffff;
    --warn: #b46f00;
    color-scheme: light;
  }
}
* { box-sizing: border-box; }
html, body { margin: 0; background: var(--bg); color: var(--text); }
body { font-size: 17px; line-height: 1.6; }
main { max-width: 720px; margin: 0 auto; padding: 24px 16px 64px; }
header.top { display: flex; align-items: center; gap: 10px; padding: 12px 16px; max-width: 720px; margin: 0 auto; }
header.top a { color: var(--text); text-decoration: none; font-weight: 700; display: flex; align-items: center; gap: 8px; }
header.top img { width: 28px; height: 28px; border-radius: 8px; }
h1 { font-size: 1.9rem; line-height: 1.2; margin: 8px 0 12px; }
h2 { font-size: 1.35rem; line-height: 1.3; margin: 36px 0 8px; }
h3 { font-size: 1.1rem; margin: 24px 0 6px; }
p, li { color: var(--text); }
.lead { font-size: 1.1rem; color: var(--muted); }
.muted, .meta { color: var(--muted); font-size: 0.9rem; }
a { color: var(--accent); }
.card { background: var(--card); border: 1px solid var(--line); border-radius: 16px; padding: 16px 18px; margin: 20px 0; }
.card.warn { border-color: var(--warn); }
.cta { background: var(--card); border: 1px solid var(--accent); border-radius: 16px; padding: 18px; margin: 28px 0; }
.cta p { margin: 0 0 12px; }
.btn { display: inline-block; background: var(--accent); color: var(--accent-ink); font-weight: 700; padding: 12px 20px; border-radius: 12px; text-decoration: none; }
table { width: 100%; border-collapse: collapse; margin: 12px 0; font-size: 0.95rem; }
th, td { text-align: left; padding: 8px 6px; border-bottom: 1px solid var(--line); vertical-align: top; }
th { color: var(--muted); font-weight: 600; }
.calc label { display: block; margin: 10px 0 4px; font-size: 0.95rem; color: var(--muted); }
.calc input, .calc select { width: 100%; padding: 10px 12px; border-radius: 10px; border: 1px solid var(--line); background: var(--bg); color: var(--text); font: inherit; }
.calc .row { display: grid; grid-template-columns: 1fr 1fr; gap: 12px; }
.calc .out { margin-top: 16px; font-size: 1.05rem; }
.calc .big { font-size: 1.8rem; font-weight: 800; color: var(--accent); }
details { margin: 10px 0; background: var(--card); border: 1px solid var(--line); border-radius: 12px; padding: 10px 14px; }
summary { cursor: pointer; font-weight: 600; }
footer { max-width: 720px; margin: 0 auto; padding: 0 16px 40px; color: var(--muted); font-size: 0.85rem; }
footer a { color: var(--muted); }
@media (max-width: 480px) { h1 { font-size: 1.55rem; } .calc .row { grid-template-columns: 1fr; } }