do you mean something like the CSS used here? if so you'll need premium for that (a paid feature that can be found in your settings)
there's also extensions you can use to customize your toyhouse look such as this one, but it will only be seen on your end and not others
you could also use html layouts that look like CSS like these if you don't mind it only applying to that specific page and not others (however I don't really recommend them since quite a few users have CSS disabled for one reason or another (like accessibility) and you can't disable html)
if you don't mean anything here, do you mind explaining a bit more on what you're looking for?