:root {
  --ink: #1f2933;
  --muted: #5f6b7a;
  --line: #d9dee5;
  --soft: #f4f6f8;
  --accent: #d4571d;
  --accent-soft: #fdeee6;
  --bg: #ffffff;
}

* { box-sizing: border-box; }

html { -webkit-text-size-adjust: 100%; }

body {
  margin: 0;
  background: var(--bg);
  color: var(--ink);
  font-family: "Pretendard", "Apple SD Gothic Neo", "Noto Sans KR", -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  font-size: 16px;
  line-height: 1.7;
  word-break: keep-all;
  overflow-wrap: break-word;
}

.wrap { max-width: 840px; margin: 0 auto; padding: 48px 24px 72px; }

.top { display: flex; align-items: baseline; justify-content: space-between; gap: 16px; }
.top h1 { margin: 0; font-size: 34px; letter-spacing: -0.02em; }
.top .lang { font-size: 14px; color: var(--muted); text-decoration: none; border: 1px solid var(--line); border-radius: 999px; padding: 4px 12px; white-space: nowrap; }
.top .lang:hover { border-color: var(--accent); color: var(--accent); }
.subtitle { margin: 4px 0 28px; color: var(--muted); font-size: 17px; }

.profile { display: grid; grid-template-columns: 88px 1fr; gap: 6px 16px; margin: 0 0 20px; padding: 0 0 24px; border-bottom: 1px solid var(--line); }
.profile dt { font-weight: 700; }
.profile dd { margin: 0; }

.note { background: var(--soft); border-radius: 8px; padding: 12px 16px; color: var(--muted); font-size: 14px; margin: 0 0 32px; }

.toc h2 { font-size: 18px; margin: 0 0 8px; }
.toc ol { margin: 0; padding: 0; list-style: none; border-top: 1px solid var(--ink); }
.toc li { display: grid; grid-template-columns: 28px 1fr auto; gap: 12px; padding: 10px 0; border-bottom: 1px solid var(--line); }
.toc li a { color: var(--ink); text-decoration: none; }
.toc li a:hover { color: var(--accent); }
.toc .n { color: var(--muted); }
.toc .tech { color: var(--muted); font-size: 14px; text-align: right; }

.case { margin-top: 72px; scroll-margin-top: 24px; }
.case .kicker { color: var(--accent); font-weight: 700; font-size: 14px; }
.case h3 { font-size: 24px; line-height: 1.4; margin: 4px 0 6px; letter-spacing: -0.01em; }
.case .meta { color: var(--muted); font-size: 14px; margin: 0 0 20px; }

figure { margin: 0 0 24px; border: 1px solid var(--line); border-radius: 10px; padding: 20px 16px 14px; }
figcaption { color: var(--muted); font-size: 13px; text-align: center; margin-top: 12px; }

.flow { display: flex; align-items: center; justify-content: center; flex-wrap: nowrap; gap: 6px; }
.flow + .flow, .flow + .down, .down + .flow, .flow + .grid4, .down + .grid4 { margin-top: 10px; }
.node { background: var(--soft); border: 1px solid var(--line); border-radius: 6px; padding: 8px 10px; font-size: 13.5px; line-height: 1.45; text-align: center; }
.node.hot { background: var(--accent-soft); border-color: var(--accent); }
.arr { color: var(--muted); font-size: 18px; flex: none; }
.down { text-align: center; color: var(--muted); font-size: 18px; line-height: 1; }
.alts { display: grid; grid-template-columns: repeat(3, 1fr); gap: 8px; margin-top: 14px; }
.alts .pick { color: var(--accent); font-weight: 700; }

.part { display: grid; grid-template-columns: 72px 1fr; gap: 16px; margin-top: 18px; }
.part h4 { margin: 0; color: var(--accent); font-size: 15px; line-height: 1.7; }
.part ul { margin: 0; padding-left: 18px; }
.part li + li { margin-top: 6px; }

code { font-family: "SF Mono", Menlo, Consolas, monospace; font-size: 0.88em; background: var(--soft); padding: 1px 5px; border-radius: 4px; }

footer { margin-top: 80px; padding-top: 20px; border-top: 1px solid var(--line); color: var(--muted); font-size: 13px; }

@media (max-width: 640px) {
  body { font-size: 15px; }
  .wrap { padding: 32px 18px 56px; }
  .top h1 { font-size: 28px; }
  .profile { grid-template-columns: 1fr; gap: 0; }
  .profile dd + dt { margin-top: 10px; }
  .toc li { grid-template-columns: 24px 1fr; }
  .toc .tech { grid-column: 2; text-align: left; }
  .case h3 { font-size: 21px; }
  .flow { flex-direction: column; }
  .flow .arr { transform: rotate(90deg); }
  .flow.rev { flex-direction: column-reverse; }
  .node { width: 100%; }
  .alts { grid-template-columns: 1fr; }
  .part { grid-template-columns: 1fr; gap: 4px; }
}