body, html {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    font-family: Arial, sans-serif;
  }
  
  .section {
    display: flex;
    justify-content: center;
    align-items: center;
    width: 100%;
    height: 100vh;
    position: relative;
  }
  
  #section1 {
    background: black;
    color: white;
    height: 20vh;
  }
  
  #section2 {
    background: #f0f0f0;
    height: 70vh;
    position: relative;
  }
  
  #layoutPreview {
    position: relative;
    background: white;
    margin: 0 auto;
    border: 1px solid #ccc;
  }
  
  #section3 {
    background: black;
    height: 10vh;
  }
  
  button {
    background: #555;
    color: white;
    border: none;
    padding: 10px 20px;
    cursor: pointer;
  }
  
  button:hover {
    background: #777;
  }