Flow

<Flow
  as="div"
  className="500:text-20 700:text-30"
>
  ...
</Flow>

<div className="font-size_20-30_500-700">
  ...
</div>

.font-size_20-30_500-700 {
  font-size: clamp(20px, 5vw - 5px, 30px);
}