Thank you for the reply!
With some trial and error I did find that if you are adding CSS to a button to get this to work in Construct 3 you need to enter it in like this.
(System)Event: Everytick or start of layout etc.
(Button)Action: CSS style
Property name: "webkit-appearance"
then I enter all my other CSS changes and so far it is working great!
Thanks again for the information Elliott.