I'm using a few CSS definitions(for tabs) in a child theme, that also worked just fine under the parent.
Do you have firebug, are you sure it's not just a problem of CSS inheritance?
!important to your CSS rules, if that resolves the issue, then we at least know it's just a case of other rules in your stylesheet getting preference over your new rules.
Note: I think a few of your csss selectors may be a little off..
#tabs1 ul li
#tabs-1 ul li
And likewise for other rules..
Post UI Tabs uses the following format for each tab set..
Where n1 is the set of tabs(or instance) and n2 is the given tab in that set.