<div class='container'>
  <h1 class='title'>Hello World</h1>
  <p class='description'>This is a demonstration of the margin-block-start property in CSS.</p>
</div>

.container {
  background-color: #f0f0f0;
  padding: 20px;
  border: 1px solid #ccc;
}

.title {
  margin-block-start: 40px;
  color: #333;
}

the.description {
  color: #666;
}

// No JavaScript required for this demo

Hello World

This is a demonstration of the margin-block-start property in CSS.