It's true that cascading style sheets are not an ideal general user control for changing site appearance, but at least there is a control. There's always the DAZ forums for you - they unselfishly make things easy by having no options at all.

Luckily you don't have to know about computer language. If you can grasp basic copy and paste functions then you can use one of the CSS schemes that the community has shared with itself.

If you have some colours in mind - the community occasionally does requests. ;-)