:root { --fb-base: clamp(15px, 1.05vw + 0.6rem, 17px); }
  html { font-size: var(--fb-base); }
  @media (max-width: 640px) {
    h1 { font-size: clamp(1.625rem, 6vw, 2.25rem); line-height: 1.2; }
    h2 { font-size: clamp(1.25rem, 4.5vw, 1.75rem); line-height: 1.25; }
    p { font-size: 1rem; line-height: 1.65; }
    button, .btn, .cta, a.btn, a.cta {
      min-height: 44px;
      min-width: 44px;
      touch-action: manipulation;
      -webkit-tap-highlight-color: rgba(99,102,241,.15);
    }
    .container, main { padding-left: 1rem; padding-right: 1rem; }
  }
  .grid-auto-fit { display: grid; grid-template-columns: repeat(auto-fit, minmax(min(100%, 280px), 1fr)); gap: 1rem; }