:root {
  --bg: #f5f6fb;
  --card: #ffffff;
  --ink: #1c1d2b;
  --muted: #5b5d72;
  --line: #e6e7f1;
  --indigo: #4f46e5;
  --periwinkle: #7c83ff;
  --cyan: #22b8d6;
  --radius: 18px;
  --maxw: 760px;
}
@media (prefers-color-scheme: dark) {
  :root {
    --bg: #0f1017;
    --card: #181a24;
    --ink: #edeef6;
    --muted: #a6a9c0;
    --line: #262838;
  }
}
* { box-sizing: border-box; }
html { -webkit-text-size-adjust: 100%; }
body {
  margin: 0;
  background: var(--bg);
  color: var(--ink);
  font-family: -apple-system, BlinkMacSystemFont, "Apple SD Gothic Neo",
    "Pretendard", "Segoe UI", Roboto, sans-serif;
  line-height: 1.7;
  -webkit-font-smoothing: antialiased;
}
.wrap { max-width: var(--maxw); margin: 0 auto; padding: 28px 20px 72px; }
header.hero {
  background: linear-gradient(135deg, var(--indigo), var(--periwinkle) 55%, var(--cyan));
  color: #fff;
  border-radius: 22px;
  padding: 34px 28px;
  margin-bottom: 30px;
}
header.hero .brand { display: flex; align-items: center; gap: 12px; font-weight: 800; font-size: 1.5rem; }
header.hero .badge {
  display: inline-block; margin-top: 14px; padding: 6px 12px;
  background: rgba(255,255,255,.16); border-radius: 999px;
  font-size: .8rem; font-weight: 700; letter-spacing: .02em;
}
header.hero p.sub { margin: 14px 0 0; font-size: 1.05rem; opacity: .92; }
h1 { font-size: 1.7rem; margin: 0 0 6px; }
h2 { font-size: 1.2rem; margin: 32px 0 10px; }
h3 { font-size: 1.02rem; margin: 20px 0 6px; }
p, li { color: var(--ink); }
.muted { color: var(--muted); }
.meta { color: var(--muted); font-size: .9rem; margin-top: 4px; }
.card {
  background: var(--card); border: 1px solid var(--line);
  border-radius: var(--radius); padding: 22px 24px; margin-top: 18px;
}
a { color: var(--indigo); }
@media (prefers-color-scheme: dark) { a { color: var(--periwinkle); } }
ul { padding-left: 20px; }
li { margin: 6px 0; }
.nav { display: flex; gap: 18px; margin-top: 20px; flex-wrap: wrap; }
.nav a { font-weight: 600; text-decoration: none; }
footer { margin-top: 46px; color: var(--muted); font-size: .85rem; border-top: 1px solid var(--line); padding-top: 20px; }
code { background: rgba(127,131,255,.14); padding: 2px 6px; border-radius: 6px; font-size: .9em; }
table { border-collapse: collapse; width: 100%; margin-top: 10px; font-size: .95rem; }
th, td { text-align: left; padding: 10px 12px; border-bottom: 1px solid var(--line); vertical-align: top; }
th { color: var(--muted); font-weight: 600; }