Textarea too big

Hey Guys,

I need help, i am still a newbie to websites…

If you click in the bottom right of the text area you can make it so big that is goes way over the writing on the right side of the website, how can I fix this?

Is there an option to make the textarea static so you cant move it bigger ?

Thank you!

The page I need help with: [log in to see the link]