:root {
    --text-primary: #888888;
    --text-muted: #f12345;
    --bg: #ffffff;
    --accent: #aaaaaa;
  }
  
  * {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
  }
  
  html {
    font-size: clamp(15px, 1.2vw, 18px);
  }
  
  body {
    font-family: system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
    line-height: 1.65;
    color: var(--text-primary);
    background: var(--bg);
    padding: 1.5rem;
  }
  
  main {
    max-width: 72ch;
    margin: 0 auto;
    display: flex;
    flex-direction: column;
    gap: 1.6rem;
  }
  
  h1, h2, h3 {
    font-weight: 500;
    line-height: 1.25;
    color: var(--text-primary);
  }
  
  h1 {
    font-size: clamp(2rem, 4vw, 2.8rem);
  }
  
  h2 {
    font-size: clamp(1.4rem, 3vw, 1.9rem);
  }
  
  h3 {
    font-size: 1.15rem;
  }
  
  p {
    max-width: 65ch;
  }
  
  ul {
    padding-left: 1.2rem;
  }
  
  li {
    margin-bottom: 0.4rem;
  }
  
  a {
    color: var(--text-primary);
    text-decoration: none;
    border-bottom: 1px solid var(--text-muted);
  }
  
  a:hover {
    border-color: var(--accent);
  }
  
  footer {
    margin-top: 4rem;
    font-size: 0.85rem;
    color: var(--text-muted);
  }
  
  /* Diagram blocks */
  
  .diagram-block {
    margin: 3rem 0;
  }
  
  .diagram-block img {
    display: block;
    max-width: 100%;
    height: auto;
    margin-bottom: 1rem;
  }
  
  .diagram-text {
    max-width: 65ch;
  }
  
  /* Responsive */
  
  @media (min-width: 768px) {
    body {
      padding: 3rem;
    }
  
    main {
      gap: 2rem;
    }
  }
  
  @media (min-width: 1200px) {
    main {
      max-width: 80ch;
    }
  }