:root {
  --bg: #ffffff;
  --surface: #ffffff;
  --surface-alt: #f8f9fa;
  --border: #e8eaed;
  --text: #1a1a2e;
  --ts: #6b7280;
  --primary: #4f46e5;
  --primary-light: #eef2ff;
  --primary-dark: #4338ca;
  --green: #059669;
  --red: #dc2626;
  --max: 760px;
}
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }
body {
  font-family: -apple-system, BlinkMacSystemFont, 'Inter', 'Segoe UI', Roboto, sans-serif;
  background: var(--bg);
  color: var(--text);
  line-height: 1.7;
  -webkit-font-smoothing: antialiased;
}
.nav {
  background: rgba(255,255,255,.92);
  border-bottom: 1px solid var(--border);
  padding: 0 20px;
  position: sticky;
  top: 0;
  z-index: 100;
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
}
.nav-inner {
  max-width: var(--max);
  margin: 0 auto;
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 56px;
}
.nav a.logo { font-weight: 800; font-size: 1.15rem; color: var(--text); text-decoration: none; letter-spacing: -0.02em; }
.nav a.logo span { color: var(--primary); }
.nav .back { font-size: .85rem; color: var(--ts); text-decoration: none; font-weight: 500; }
.nav .back:hover { color: var(--primary); }
.container { max-width: var(--max); margin: 0 auto; padding: 48px 20px; }
.breadcrumb { font-size: .8rem; color: var(--ts); margin-bottom: 16px; }
.breadcrumb a { color: var(--primary); text-decoration: none; }
h1 { font-size: 1.9rem; font-weight: 800; line-height: 1.2; margin-bottom: 12px; letter-spacing: -0.03em; }
.meta { font-size: .82rem; color: var(--ts); margin-bottom: 32px; }
.meta .tag { display: inline-block; background: var(--primary-light); color: var(--primary); padding: 3px 10px; border-radius: 4px; font-weight: 600; margin-right: 8px; }
h2 { font-size: 1.3rem; font-weight: 700; margin: 36px 0 14px; letter-spacing: -0.01em; }
h3 { font-size: 1.05rem; font-weight: 600; margin: 24px 0 10px; }
p { font-size: .95rem; color: #374151; margin-bottom: 16px; }
ul, ol { padding-left: 22px; margin-bottom: 16px; }
li { font-size: .95rem; color: #374151; margin-bottom: 8px; }
strong { color: var(--text); }
a { color: var(--primary); text-decoration: none; }
a:hover { text-decoration: underline; }
blockquote {
  border-left: 3px solid var(--primary);
  padding: 12px 20px;
  background: var(--primary-light);
  border-radius: 0 8px 8px 0;
  margin: 20px 0;
  font-size: .9rem;
  color: var(--text);
}
code {
  background: var(--surface-alt);
  padding: 2px 6px;
  border-radius: 4px;
  font-size: .85rem;
  font-family: 'SF Mono', 'Fira Code', monospace;
}
pre {
  background: #1a1a2e;
  color: #e2e8f0;
  padding: 16px 20px;
  border-radius: 8px;
  overflow-x: auto;
  margin: 20px 0;
}
pre code { background: none; color: inherit; padding: 0; }
table { width: 100%; border-collapse: collapse; margin: 20px 0; font-size: .875rem; }
th, td { padding: 10px 14px; text-align: left; border-bottom: 1px solid var(--border); }
th { background: var(--surface-alt); font-weight: 600; font-size: .75rem; text-transform: uppercase; color: var(--ts); letter-spacing: .04em; }
.ad-slot {
  background: var(--surface-alt);
  border-radius: 10px;
  padding: 20px;
  text-align: center;
  color: var(--ts);
  font-size: .8rem;
  margin: 32px 0;
}
.cta-box {
  background: var(--primary-light);
  border: 1px solid var(--primary);
  border-radius: 10px;
  padding: 24px;
  margin: 32px 0;
  text-align: center;
}
.cta-box h3 { margin-top: 0; }
.cta-box a { display: inline-block; background: var(--primary); color: #fff; padding: 10px 24px; border-radius: 8px; font-weight: 600; margin-top: 8px; }
.cta-box a:hover { background: var(--primary-dark); text-decoration: none; }
.footer {
  text-align: center;
  padding: 32px 20px;
  border-top: 1px solid var(--border);
  font-size: .8rem;
  color: var(--ts);
  margin-top: 48px;
}
.footer a { color: var(--primary); text-decoration: none; }
@media (max-width: 600px) {
  h1 { font-size: 1.5rem; }
  .container { padding: 32px 16px; }
}