Pattern matching css rules
===

I have the following pattern:

    [\{\}].*[\{\}]

With the following test strings (can provide more if needed):

    }.prop{hello:ars;} //shouldn't match
    }#prop{} //should match
    }.prop #prop {} //should match

The purpose of the pattern is to find empty css rulesets. Can someone suggest how I go about excluding matches with characters between the second set of brackets? I will be updating the pattern as I get closer to a solution.