Resizable text fields need limits

[kroppt]

I have some simple recommendations. I could not figure out how development works using git and zites, so I'll just lay it out here.

I believe it looks strange for the comment_body and topic_body elements to be able to be horizontally resized. It would make sense to set resize: vertical. The topic_body element is especially messed up on horizontal resize.

It also makes sense to me to set the minimum height of the textareas to the height of a line (24px) plus the paddings (20px) and borders (4px) = 48px, which looks like this:

comment_body:

topic_body:

Thanks.