:root {
  --bn-primary: #2563eb;
  --bn-primary-hover: #1d4ed8;
  --bn-secondary: #1e40af;
  --bn-text: #1e293b;
  --bn-muted: #64748b;
  --bn-bg: #ffffff;
  --bn-border: #e2e8f0;
  --bn-radius: 8px;
}

* { box-sizing: border-box; }
body {
  margin: 0;
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
  font-size: 16px;
  line-height: 1.6;
  color: var(--bn-text);
  background: var(--bn-bg);
  -webkit-font-smoothing: antialiased;
}

.bn-page { min-height: 100vh; display: flex; flex-direction: column; }
.bn-main { flex: 1; }

.bn-header,
.bn-main,
.bn-footer {
  width: 100%;
  max-width: 720px;
  margin-left: auto;
  margin-right: auto;
  padding: 1rem 1.25rem;
}
@media (min-width: 640px) {
  .bn-header,
  .bn-main,
  .bn-footer { padding: 1.5rem 2rem; }
}

.bn-header {
  border-bottom: 1px solid var(--bn-border);
  padding-top: 1rem;
  padding-bottom: 1rem;
}
.bn-nav {
  display: flex;
  flex-wrap: wrap;
  gap: 0.75rem 1.25rem;
}
.bn-nav a {
  color: var(--bn-primary);
  text-decoration: none;
  font-weight: 500;
}
.bn-nav a:hover { color: var(--bn-primary-hover); text-decoration: underline; }

.bn-breadcrumb {
  font-size: 0.813rem;
  color: var(--bn-muted);
  margin-bottom: 1rem;
}
.bn-breadcrumb a {
  color: var(--bn-primary);
  text-decoration: none;
}
.bn-breadcrumb a:hover { text-decoration: underline; }

.bn-main h1 {
  font-size: 1.5rem;
  font-weight: 700;
  line-height: 1.3;
  margin: 0 0 1rem 0;
}
@media (min-width: 640px) {
  .bn-main h1 { font-size: 1.75rem; }
}

.bn-main h2 {
  font-size: 1.15rem;
  font-weight: 600;
  margin: 2rem 0 0.75rem 0;
}
@media (min-width: 640px) {
  .bn-main h2 { font-size: 1.25rem; }
}

.bn-main h3 {
  font-size: 1rem;
  font-weight: 600;
  margin: 1.5rem 0 0.5rem 0;
}

.bn-main p { margin: 0 0 1rem 0; }
.bn-intro { margin-bottom: 1.5rem; }

.bn-sbody ul,
.bn-sbody ol {
  margin: 0.75rem 0 1rem 1.25rem;
  padding-left: 1.25rem;
}
.bn-sbody li { margin-bottom: 0.4rem; }

.bn-sbody table {
  width: 100%;
  border-collapse: collapse;
  margin: 1rem 0;
  font-size: 0.9rem;
  overflow-x: auto;
  display: block;
}
@media (min-width: 480px) {
  .bn-sbody table { display: table; }
}
.bn-sbody th,
.bn-sbody td {
  border: 1px solid var(--bn-border);
  padding: 0.6rem 0.75rem;
  text-align: left;
}
.bn-sbody th {
  background: var(--bn-border);
  font-weight: 600;
}

.bn-faq { margin-top: 2rem; }
.bn-faq h3 {
  font-size: 0.95rem;
  font-weight: 600;
  color: var(--bn-text);
}

.bn-related ul {
  list-style: none;
  margin: 0;
  padding: 0;
}
.bn-related li {
  margin: 0.5rem 0;
  padding: 0.5rem 0;
  border-bottom: 1px solid var(--bn-border);
}
.bn-related li:last-child { border-bottom: none; }
.bn-related a {
  color: var(--bn-primary);
  text-decoration: none;
}
.bn-related a:hover { text-decoration: underline; }

.bn-footer {
  margin-top: 2rem;
  padding-top: 1.5rem;
  border-top: 1px solid var(--bn-border);
  font-size: 0.875rem;
  color: var(--bn-muted);
}
.bn-footer a {
  color: var(--bn-primary);
  text-decoration: none;
}
.bn-footer a:hover { text-decoration: underline; }

.bn-hubinfo {
  color: var(--bn-muted);
  margin-bottom: 1.5rem;
}
.bn-plist {
  list-style: none;
  margin: 0;
  padding: 0;
}
.bn-plist li {
  margin: 0;
  padding: 0.75rem 0;
  border-bottom: 1px solid var(--bn-border);
}
.bn-plist li:last-child { border-bottom: none; }
.bn-plist a {
  color: var(--bn-primary);
  text-decoration: none;
  display: block;
}
.bn-plist a:hover { text-decoration: underline; }

.bn-pager {
  display: flex;
  align-items: center;
  gap: 1rem;
  margin-top: 2rem;
  flex-wrap: wrap;
}
.bn-pager a {
  color: var(--bn-primary);
  text-decoration: none;
  padding: 0.5rem 1rem;
  background: var(--bn-bg);
  border: 1px solid var(--bn-border);
  border-radius: var(--bn-radius);
}
.bn-pager a:hover {
  background: var(--bn-primary);
  color: white;
  border-color: var(--bn-primary);
}
.bn-pginfo {
  color: var(--bn-muted);
  font-size: 0.875rem;
}