I searched around and allegedly, body:nth-of-type(1)
is used in CSS to target only Safari and Google Chrome.
Lo and behold, Mozilla reads it properly to
@media screen and (-webkit-min-device-pixel-ratio:0) { ... styles go here ... }
There is no CSS for only Chrome (AFAIK) but Chrome AND Safari. You may consider a Javascript solution.
UPDATE Jan 22, 2013: As mentioned in the comments, this may no longer be safe. I could not find a suitable alternative.