:root {
    --bg: #fafafa;
    --card: #ffffff;
    --ink: #0a0a0a;
    --muted: #6b7280;
    --accent: #000;
    --border: #e5e7eb;
    --radius: 16px;
    --shadow: 0 1px 2px rgba(0,0,0,.06), 0 8px 20px rgba(0,0,0,.06);
    --shadow-hover: 0 2px 4px rgba(0,0,0,.07), 0 12px 28px rgba(0,0,0,.1);
    --maxw: 1100px;
  }
  
  html, body {
    height: 100%;
  }
  * {
    box-sizing: border-box;
  }
  body {
    margin: 0;
    font-family: ui-sans-serif, system-ui, Helvetica, Arial;
    background: var(--bg);
    color: var(--ink);
    line-height: 1.5;
    -webkit-font-smoothing: antialiased;
  }
  
  a {
    color: #000;
    text-decoration: none;
  }
  a:focus {
    outline: 2px solid var(--accent);
    outline-offset: 2px;
  }
  .container {
    max-width: var(--maxw);
    margin: 0 auto;
    padding: 0 20px;
  }
  
  /* Header */
  header {
    position: sticky;
    top: 0;
    z-index: 10;
    backdrop-filter: saturate(180%) blur(8px);
    background: rgba(250,250,250,.75);
    border-bottom: 1px solid var(--border);
  }
  .nav {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 16px;
    padding: 14px 0;
  }
  .brand {
    display: flex;
    align-items: baseline;
    gap: 10px;
  }
  .brand h1 {
    margin: 0;
    font-size: 18px;
    font-weight: 700;
  }
  .brand .dot {
    width: 6px;
    height: 6px;
    border-radius: 999px;
    background: var(--ink);
    opacity: .7;
  }
  .nav a {
    font-size: 14px;
    opacity: .85;
  }
  .nav a:hover {
    opacity: 1;
    text-decoration: underline;
  }
  
  /* Hero */
  .hero {
    padding: 48px 0 8px;
  }
  .eyebrow {
    font-size: 13px;
    letter-spacing: .18em;
    color: var(--muted);
  }
  .title {
    font-size: clamp(28px, 4vw, 44px);
    line-height: 1.1;
    margin: .4rem 0 .25rem;
    font-weight: 800;
  }
  .subtitle {
    font-size: 18px;
    color: var(--muted);
  }
  
  /* Section */
  section {
    padding: 28px 0 8px;
  }
  .section-head {
    display: flex;
    align-items: center;
    justify-content: space-between;
    margin-bottom: 12px;
  }
  .section-head h2 {
    margin: 0;
    font-size: 14px;
    letter-spacing: .18em;
    color: var(--muted);
  }
  
  /* Two-column layout */
  .two-col {
    display: grid;
    gap: 24px;
    grid-template-columns: 1fr;
  }
  @media (min-width: 900px) {
    .two-col {
      grid-template-columns: 1fr 1fr;
    }
  }
  
  /* Cards */
  .grid {
    display: grid;
    gap: 16px;
    grid-template-columns: repeat(1, minmax(0, 1fr));
  }
  @media (min-width: 600px) {
    .grid {
      grid-template-columns: repeat(2, minmax(0, 1fr));
    }
  }
  .card {
    display: block;
    background: var(--card);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    padding: 18px;
    box-shadow: var(--shadow);
    transition: box-shadow .25s ease, transform .25s ease, border-color .25s ease;
    color: var(--ink);
    height: 8.5em;
  }
  .card:hover {
    transform: translateY(-2px);
    box-shadow: var(--shadow-hover);
    border-color: #d1d5db;
  }
  .card h3 {
    margin: 0 0 8px;
    font-size: 18px;
  }
  .card p {
    margin: 0;
    color: #374151;
    font-size: 14px;
  }
  .card .arrow {
    float: right;
    opacity: 0;
    transition: opacity .2s;
  }
  .card:hover .arrow {
    opacity: 1;
  }
  
  /* Typography */
  .adTypography {
    text-indent: 1.5em;
  }

  #affinityDiagram {
    max-width: var(--maxw);
    margin: 0 auto;
    padding: 0 20px;
  }


  /* Footer */
  footer {
    border-top: 1px solid var(--border);
    margin-top: 40px;
    padding: 28px 0;
  }
  .foot {
    display: flex;
    gap: 16px;
    align-items: center;
    justify-content: space-between;
    flex-wrap: wrap;
  }
  .foot small {
    color: var(--muted);
  }