It could be your display: -webkit-inline;. Remove that and see what happens... I never use webkit rules so I am not even sure if the syntax is right(Someone please correct me. I did a search and couldn't find anything).
Because you are supplying only a portion of you code it is hard to tell why. So if the above does not help, please post both your full CSS and your HTML (with DOCTYPE) so we may better understand what the issue might be.
The best way to avoid browser specific display issues is to write and validate your HTML and CSS to W3C specifications and to NOT use goofy non-standard stuff (e.g. "display: -webkit-inline;"). Personally I use HTML4.01 Strict and CSS2.1 as my design specifications.
Honest to god, sticking to W3C specifications will make your life easier.
Get the Firefox "Web Developer" extension, it will allow you to validate your code from the right mouse click context menu.