If you have your list of favorite sites to the left, hit the x to get rid of it. That should expand the width of your screen. otherwise, click on the center button of the 3 buttons at the top right. the - then 2 boxes then the x. click the 2 boxes until your screen is full sized. this is the maximum size possible.
You can also click on view and text size, that might help.
Or, press F11.