I would like the question to be in the middle of the browser?
If you want to center just some of your questions, give each one
Edit -> Layout -> CSS Class Name = centerme
Then create custom css like:
margin: 0 auto;
If you want all questions centered, use .sg-question instead of .centerme in the css and you won’t need to add the centerme class name to the questions. To me this won’t look good unless all of your questions have a similar natural width.
Editing the CSS is done on the Style tab by scrolling to the bottom and clicking on HTML/CSS Editor.