* {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

body {
  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, Cantarell, sans-serif;
  font-size: 18px;
  line-height: 1.6;
  color: #1a1a1a;
  background: #fafafa;
}

a {
  color: #0066cc;
  text-decoration: none;
  border-bottom: 1px solid transparent;
  transition: border-color 0.2s ease;
}

a:hover {
  border-bottom-color: #0066cc;
}

/* Layout */

.container {
  max-width: 640px;
  margin: 0 auto;
  padding: 0 24px;
}

/* Header */

.site-header {
  padding: 40px 0 0;
}

.site-header a {
  color: inherit;
  border-bottom: none;
}

.site-name {
  font-size: 1.1rem;
  font-weight: 600;
  letter-spacing: -0.01em;
}

.site-header::after {
  content: '';
  display: block;
  margin-top: 16px;
  border-bottom: 1px solid #e8e8e8;
}

/* Hero */

.hero {
  padding: 40px 0 60px;
}

.hero h1 {
  font-size: 2.4rem;
  font-weight: 700;
  letter-spacing: -0.02em;
  line-height: 1.2;
  margin-bottom: 24px;
}

.hero p {
  color: #333;
  margin-bottom: 16px;
}

.hero p:last-child {
  margin-bottom: 0;
}

/* Callout (homepage) */

.callout {
  background: #fff;
  border: 1px solid #e0e0e0;
  border-radius: 8px;
  padding: 32px;
  margin-bottom: 60px;
}

.callout h2 {
  font-size: 1.2rem;
  font-weight: 600;
  margin-bottom: 8px;
}

.callout p {
  color: #555;
  margin-bottom: 16px;
}

.callout-link {
  display: inline-block;
  font-weight: 500;
  border-bottom: 1px solid #0066cc;
}

/* Article */

.article {
  padding: 40px 0 60px;
}

.article h1 {
  font-size: 2rem;
  font-weight: 700;
  letter-spacing: -0.02em;
  line-height: 1.2;
  margin-bottom: 32px;
}

.article h2 {
  font-size: 1.3rem;
  font-weight: 700;
  margin-top: 48px;
  margin-bottom: 16px;
  color: #111;
  padding-top: 32px;
  border-top: 1px solid #e8e8e8;
}

.article h2:first-of-type {
  border-top: none;
  padding-top: 0;
  margin-top: 40px;
}

.article h3 {
  font-size: 1.1rem;
  font-weight: 700;
  margin-top: 32px;
  margin-bottom: 12px;
  color: #111;
}

.article p {
  color: #333;
  margin-bottom: 16px;
}

.article strong {
  color: #111;
}

.article ul,
.article ol {
  margin: 20px 0;
  padding-left: 24px;
  color: #333;
}

.article ul li,
.article ol li {
  margin-bottom: 8px;
}

/* Pull Quotes */

.pull-quote {
  border-left: 3px solid #0066cc;
  padding-left: 20px;
  margin: 28px 0;
  font-size: 1.05em;
  font-style: italic;
  color: #2a2a2a;
}

.pull-quote strong {
  font-style: italic;
}

/* Article Callout Boxes */

.callout-example {
  border-left: 3px solid #4a90d9;
  background: #f5f8fc;
  padding: 16px 20px;
  margin: 24px 0;
  border-radius: 0 4px 4px 0;
}

.callout-important {
  border-left: 3px solid #d4a843;
  background: #fdf8ef;
  padding: 16px 20px;
  margin: 24px 0;
  border-radius: 0 4px 4px 0;
}

/* Stage Indicators */

.stage {
  display: flex;
  align-items: center;
  gap: 12px;
}

.stage::before {
  content: attr(data-number);
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 28px;
  height: 28px;
  min-width: 28px;
  border-radius: 50%;
  background: #0066cc;
  color: #fff;
  font-size: 0.8rem;
  font-weight: 600;
  line-height: 1;
}

/* Principle Indicators */

.principle {
  display: flex;
  align-items: center;
  gap: 12px;
}

.principle::before {
  content: attr(data-number);
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 28px;
  height: 28px;
  min-width: 28px;
  border-radius: 50%;
  background: #555;
  color: #fff;
  font-size: 0.8rem;
  font-weight: 600;
  line-height: 1;
}

/* Feature Highlights */

.feature-highlight {
  background: #fff;
  border: 1px solid #e8e8e8;
  border-left: 3px solid #0066cc;
  padding: 20px 24px;
  margin: 20px 0;
  border-radius: 0 6px 6px 0;
}

/* Footer */

.site-footer {
  padding: 40px 0;
  border-top: 1px solid #e8e8e8;
  color: #888;
  font-size: 0.9rem;
}

.site-footer a {
  color: #555;
}

.site-footer a:hover {
  color: #0066cc;
}

/* Responsive */

@media (max-width: 480px) {
  body {
    font-size: 16px;
  }

  .hero {
    padding: 60px 0 40px;
  }

  .hero h1 {
    font-size: 1.9rem;
  }

  .callout {
    padding: 24px;
  }

  .article h1 {
    font-size: 1.7rem;
  }

  .article h2 {
    font-size: 1.15rem;
  }

  .article h3 {
    font-size: 1.05rem;
  }
}