Increase number of rows of text input for basic question type

I am trying to figure out how to change the height or number of rows of the textarea for basic text input questions. I don’t want to do a free-response assessment because I am just gathering responses for data collection. They aren’t going to be self graded, peer graded, or instructor graded.

Here is the code.

<p>Try your best to simplify the wording without losing the original meaning.</p>
<label>Then, paste your simplified version in the box below.</label>
<additional_answer answer="optional acceptable variant of the correct answer"/>
  <textline size="120"/>
</stringresponse>
</problem>

I was able to lengthen the box by changing <textline size="20"/> to 120. But how do I make the box taller? In regular CSS it’s called rows="" but I don’t know what it is in the edX lingo.

Thanks!