Try using Firefox with the Firebug add-on for this kind of CSS work.
http://getfirebug.com/
So, it isn’t possible to do it from wordpress??
Yes but you need to learn how to use CSS. It is beyond the scope of these forums to deal with basic CSS issues. Try a dedicated CSS resource such as http://www.css-discuss.org/ instead.
it isn’t possible to do it from wordpress??
Firebug (there are similar tools for some other browsers)is only a tool to investigate which styles are applied to the menu items, for instance, and to try what to change;
the final changes need to be made within style.css of your theme.
you will need to know you way around css.
http://www.w3schools.com/css/css_link.asp
helping with fundamental formatting issues is not within the scope of this WordPres forum.
ok, thank you very much for the links.