:root {
  --accent: #1d4ed8;
  --accent-dark: #1e3a8a;
  --ink: #191f28;
  --soft: #4e5968;
  --faint: #8b95a1;
  --bg: #f5f7fa;
  --line: #e7ebf0;
  --shadow: 0 1px 2px rgba(15, 23, 42, .04), 0 14px 38px rgba(15, 23, 42, .07);
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  margin: 0;
  color: var(--ink);
  background: #fff;
  font-family: "Pretendard Variable", Pretendard, -apple-system, BlinkMacSystemFont, "Segoe UI", "Malgun Gothic", sans-serif;
  line-height: 1.68;
  -webkit-font-smoothing: antialiased;
}
a { color: inherit; }
.wrap { width: min(100% - 44px, 920px); margin: 0 auto; }

header {
  position: sticky;
  top: 0;
  z-index: 50;
  border-bottom: 1px solid var(--line);
  background: rgba(255, 255, 255, .9);
  backdrop-filter: blur(12px);
}
.nav {
  width: min(100% - 44px, 1080px);
  height: 66px;
  margin: 0 auto;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 20px;
}
.logo {
  color: var(--accent-dark);
  font-size: 23px;
  font-weight: 850;
  text-decoration: none;
}
.nav-right { display: flex; align-items: center; gap: 12px; }
.back { color: var(--soft); font-size: 14px; font-weight: 700; text-decoration: none; }
.back:hover { color: var(--accent); }
.lang { position: relative; }
.lang-btn {
  min-height: 40px;
  padding: 8px 13px;
  border: 1px solid var(--line);
  border-radius: 999px;
  color: var(--soft);
  background: #fff;
  font: 700 13px/1 inherit;
  cursor: pointer;
}
.lang-menu {
  position: absolute;
  top: 48px;
  right: 0;
  z-index: 60;
  display: none;
  min-width: 150px;
  padding: 6px;
  border: 1px solid var(--line);
  border-radius: 12px;
  background: #fff;
  box-shadow: var(--shadow);
}
.lang-menu.open { display: block; }
.lang-menu button {
  width: 100%;
  padding: 10px 12px;
  border: 0;
  border-radius: 8px;
  color: var(--soft);
  background: transparent;
  font: 650 14px/1.3 inherit;
  text-align: left;
  cursor: pointer;
}
.lang-menu button:hover { background: var(--bg); }
.lang-menu button.on { color: var(--accent); background: #eef5ff; font-weight: 800; }

main { padding: 82px 0 96px; }
.eyebrow {
  display: inline-flex;
  padding: 6px 12px;
  border-radius: 999px;
  color: var(--accent-dark);
  background: #eef5ff;
  font-size: 12px;
  font-weight: 800;
}
h1 {
  max-width: 760px;
  margin: 18px 0 8px;
  font-size: clamp(38px, 6vw, 62px);
  line-height: 1.08;
  letter-spacing: 0;
}
.updated { color: var(--faint); font-size: 13px; font-weight: 650; }
.intro { max-width: 760px; margin: 28px 0 0; color: var(--soft); font-size: 18px; }
.note {
  margin-top: 28px;
  padding: 15px 17px;
  border: 1px solid #cfe0ff;
  border-radius: 8px;
  color: #29466f;
  background: #f4f8ff;
  font-size: 13px;
}
.toc {
  margin: 34px 0 56px;
  padding: 24px 26px;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: var(--bg);
}
.toc b { display: block; margin-bottom: 12px; font-size: 15px; }
.toc ol { margin: 0; padding-left: 22px; columns: 2; column-gap: 44px; }
.toc li { break-inside: avoid; margin: 7px 0; padding-left: 3px; color: var(--soft); font-size: 14px; }
.toc a { text-decoration: none; }
.toc a:hover { color: var(--accent); text-decoration: underline; }
article { max-width: 760px; }
article h2 {
  margin: 56px 0 15px;
  padding-top: 10px;
  font-size: 24px;
  line-height: 1.3;
  letter-spacing: 0;
}
article p { margin: 0 0 16px; color: var(--soft); }
article ul { margin: 12px 0 20px; padding-left: 24px; color: var(--soft); }
article li { margin: 7px 0; }
article b { color: var(--ink); }
article a { color: var(--accent); text-underline-offset: 3px; }

footer { border-top: 1px solid var(--line); padding: 38px 0 44px; color: var(--faint); font-size: 13px; }
footer .wrap { display: flex; align-items: center; justify-content: space-between; gap: 22px; }
.footlinks { display: flex; flex-wrap: wrap; gap: 18px; }
.footlinks a { color: var(--soft); font-weight: 650; text-decoration: none; }
.footlinks a:hover { color: var(--accent); }

@media (max-width: 680px) {
  .wrap, .nav { width: min(100% - 32px, 920px); }
  .nav { height: 62px; }
  .back { display: none; }
  main { padding: 58px 0 72px; }
  h1 { font-size: 38px; }
  .intro { font-size: 16px; }
  .toc { padding: 20px; margin-bottom: 44px; }
  .toc ol { columns: 1; }
  article h2 { margin-top: 44px; font-size: 21px; }
  footer .wrap { align-items: flex-start; flex-direction: column; }
}