<div>
  <p>Example text : Trying out the <code>block-size</code> CSS Logical property</p>
</div>

div {
  writing-mode: vertical-lr;
  block-size: 300px;
  width: 800px;
}

/* PRESENTATIONAL STYLES */
body {
  font-family: Arial;
  font-size: 24px;
  margin: 50px;
  background: #000;
  color: #fff;
}

div {
  border: 2px dashed #fff;
  padding: 10px;
}