will this repetitive animation code slow down my system?:
@-webkit-keyframes animate {-webkit-animation-iteration-count:infinite;...}
Are all CSS3 properties CPU intensive ?
Thanks.
Each browser has its own implementation of CSS3 and the ways the effects are processed and rendered vary. One browser will choke on certain things while another might not. You're best off just being prudent: don't overuse the CSS3 effects and everything will be fine. If you are really concerned about performance, you can always try to test the site using an old laptop or something. If it chokes - you might have exaggerated with the gradients or something.
As one of my fellow programmers says (in regard to C++ applications, but it's perfectly applicable here): don't worry about performance issues until you actually notice them :).