background-color不适用于：已访问但如果我将任何背景颜色添加到{background：#fff},它是否有效,这是一个错误吗？
看到这个例子http://jsfiddle.net/jitendravyas/CMWWm/1/绿色背景a：访问将无法正常工作.但
现在,如果我在顶部添加{background：#fff},那么a：绿色背景将开始工作. http://jsfiddle.net/jitendravyas/D6vGX/1/
解决方法
检查一下,Firefox做一些与隐私相关的修改：访问过,看起来很奇怪,
We’re limiting the CSS properties that can be used to style visited
links to color,background-color,border-*-color,and outline-color
and the color parts of the fill and stroke properties. For any other
parts of the style for visited links,the style for unvisited links is
used instead.
– 来自mozilla
http://hacks.mozilla.org/2010/03/privacy-related-changes-coming-to-css-vistited/
