Too much white space in survey - how to change it?

I'm developing a new survey and I want to decrease the amount of white space that shows up for the survey participant.
First, it looks like the questions only take up about 2/3rds of the full page width. I don't want to run the full width of the page, but there's an awful lot of WS to either side of the question.
The second thing is that for some of the questions with slider bars, the slider text/area looks really big. In one case a single question takes up most of the web page (and it's only got like 5 sliders in it, so not a huge amount).
I'm not a CSS expert, but would welcome some advice on how I can shrink the WS and make the survey look more compact and balanced.