:root {
  --blue: #2563EB;
  --blue-bg: #DBEAFE;
  --text: #0F172A;
  --subtle: #6B7280;
  --line: #E5E7EB;
  --bg: #FFFFFF;
  --bg-soft: #F9FAFB;
  --green: #16A34A;
}

@font-face {
  font-family: 'Pretendard';
  font-weight: 45 920;
  font-display: swap;
  src: url('https://cdn.jsdelivr.net/gh/orioncactus/pretendard@v1.3.9/dist/web/variable/woff2/PretendardVariable.woff2') format('woff2-variations');
}

* { box-sizing: border-box; }

html, body {
  margin: 0;
  padding: 0;
  background: var(--bg-soft);
  color: var(--text);
  font-family: 'Pretendard', -apple-system, BlinkMacSystemFont, system-ui, sans-serif;
  font-size: 15px;
  line-height: 1.7;
  -webkit-font-smoothing: antialiased;
}

.container {
  max-width: 720px;
  margin: 0 auto;
  padding: 0 20px;
}

.brand {
  background: var(--bg);
  border-bottom: 1px solid var(--line);
  padding: 24px 0 16px;
}

.brand-row {
  display: flex;
  align-items: center;
  gap: 14px;
}

.brand-icon {
  width: 56px;
  height: 56px;
  border-radius: 13px;
  background: var(--bg-soft);
}

.brand-title {
  margin: 0;
  font-size: 20px;
  font-weight: 700;
  letter-spacing: -0.01em;
}

.brand-sub {
  margin: 2px 0 0;
  font-size: 13px;
  color: var(--subtle);
}

nav {
  background: var(--bg);
  border-bottom: 1px solid var(--line);
  overflow-x: auto;
  position: sticky;
  top: 0;
  z-index: 10;
}

nav ul {
  list-style: none;
  margin: 0;
  padding: 0;
  display: flex;
  gap: 4px;
}

nav a {
  display: inline-block;
  padding: 12px 14px;
  color: var(--subtle);
  text-decoration: none;
  font-size: 14px;
  font-weight: 500;
  white-space: nowrap;
  border-bottom: 2px solid transparent;
}

nav a.active {
  color: var(--blue);
  border-bottom-color: var(--blue);
  font-weight: 600;
}

main {
  background: var(--bg);
  margin: 16px auto;
  border-radius: 12px;
  padding: 28px 24px 32px;
  border: 1px solid var(--line);
}

main h1 {
  font-size: 24px;
  font-weight: 700;
  margin: 0 0 18px;
  letter-spacing: -0.02em;
}

main h2 {
  font-size: 17px;
  font-weight: 700;
  margin: 32px 0 10px;
  letter-spacing: -0.01em;
}

main h3 {
  font-size: 15px;
  font-weight: 600;
  margin: 22px 0 8px;
  color: var(--text);
}

main p, main li {
  font-size: 14.5px;
  color: var(--text);
}

main ul, main ol {
  padding-left: 22px;
}

main li { margin: 4px 0; }

main hr {
  border: 0;
  border-top: 1px solid var(--line);
  margin: 28px 0;
}

main table {
  width: 100%;
  border-collapse: collapse;
  margin: 14px 0;
  font-size: 13.5px;
}

main th, main td {
  padding: 10px 12px;
  border: 1px solid var(--line);
  text-align: left;
  vertical-align: top;
}

main th {
  background: var(--bg-soft);
  font-weight: 600;
}

main strong { font-weight: 700; }

main a {
  color: var(--blue);
  text-decoration: none;
}

main a:hover { text-decoration: underline; }

.callout {
  background: var(--blue-bg);
  border-left: 3px solid var(--blue);
  padding: 14px 16px;
  border-radius: 6px;
  margin: 16px 0;
  font-size: 14px;
}

.callout-soft {
  background: var(--bg-soft);
  border: 1px solid var(--line);
  border-radius: 8px;
  padding: 16px;
  margin: 14px 0;
}

footer {
  text-align: center;
  padding: 28px 20px 36px;
  color: var(--subtle);
  font-size: 13px;
  line-height: 1.6;
}

footer a {
  color: var(--subtle);
  text-decoration: none;
}

footer a:hover { color: var(--blue); }

@media (max-width: 480px) {
  main { border-radius: 0; border-left: 0; border-right: 0; padding: 22px 18px 26px; }
  main h1 { font-size: 21px; }
  .container { padding: 0 14px; }
  .brand { padding: 18px 0 12px; }
}