Select a theme
You can select another theme than the default one (it si called "DevEx". A theme will influence on all the pages, but be aware; Some themes are not very nice.
A theme is remembered by the cache in your browser. So on the same computer, the theme will be kept until you clear the browsers cache, or of course change to another theme.
This is how you change theme:
You can have a look at themes on this page.