Why does Safari pick a grey color instead of the white color

I'm currently working on a site for a company and they wanted a menu on the top of the page. Everything works fine in most modern browsers, exept Safari. In safari the color of the text in the menu is grey unless you hover the menu items fast and af开发者_如何学编程ter that they stay white or jump back to grey. The other browsers all show the right white color.

I made a screenshot of the Firefox(IE 9 and Chrome) version and the Safari version. http://img707.imageshack.us/img707/8493/bothd.png

Here is the fiddle i'm currently testing in: http://jsfiddle.net/StevenVenmans/RNNPj/

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using two kind of color definitions in the css, remove the first one and try, i am talking about

 1. color: rgba(255,255,255,1);    
 2. color:#FFFFFF;`