Bounding Box too wide

Please see the site page at https://buddhabackup.com/bug-report/ You will notice that the bounding box around the UserName/Login area extends too far to the right. Can you direct me to the area to shorten this or give me the code to do so? An option would also be to remove the bounding box altogether.
Many thanks.

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