:root {
  color-scheme: dark;
  --bg: #090d14;
  --panel: #111722;
  --line: #263245;
  --text: #f4f7fb;
  --muted: #91a0b6;
  --green: #55dda2;
  --blue: #69a8ff;
}
* { box-sizing: border-box; }
body {
  margin: 0;
  min-height: 100vh;
  font-family: Pretendard, "Noto Sans KR", system-ui, sans-serif;
  color: var(--text);
  background: radial-gradient(circle at 16% -10%, rgba(105,168,255,.14), transparent 34%), var(--bg);
}
.wrap { width: min(780px, calc(100% - 32px)); margin: 0 auto; }
header { border-bottom: 1px solid rgba(255,255,255,.07); }
header .wrap { min-height: 68px; display: flex; align-items: center; justify-content: space-between; gap: 16px; }
.brand { color: var(--text); font-weight: 850; text-decoration: none; letter-spacing: -.04em; }
.back { color: var(--muted); font-size: 13px; text-decoration: none; }
main { padding: 48px 0 80px; }
.eyebrow { color: var(--green); font-size: 12px; font-weight: 800; letter-spacing: .08em; }
h1 { margin: 10px 0 14px; font-size: clamp(32px, 6vw, 50px); letter-spacing: -.055em; }
.lead { margin: 0 0 32px; color: var(--muted); line-height: 1.7; }
section { margin-top: 14px; padding: 24px; border: 1px solid var(--line); border-radius: 16px; background: var(--panel); }
h2 { margin: 0 0 12px; font-size: 19px; letter-spacing: -.03em; }
p, li { color: var(--muted); line-height: 1.7; font-size: 14px; }
strong { color: var(--text); }
a { color: var(--blue); }
.formula { padding: 16px; border-radius: 12px; background: #0c131d; color: #cbd6e5; font-size: 13px; line-height: 1.65; }
footer { padding: 24px 0; border-top: 1px solid rgba(255,255,255,.06); color: var(--muted); font-size: 12px; }