Webpage Demo : Enlarge entry box

[meteorquake]

The website demo is very handy for being online wherever you are -
https://esprima.org/demo/validate.html
It's very handy for checking serverside JS that reports a syntax problem but no details.
Can I recommend the code box be made somewhat larger, such as a % of available width and height?
If not the fullest size then an "enlarge" button that makes it as large as can be done would also be useful.
Cheers! David