您可以使用 CSS2系统颜色-请注意，CSS3中已弃用这些颜色，建议改用外观属性。

You could use CSS2 system colors - note that these are deprecated in CSS3 and appearance property is advised to use instead.

ul { -color：背景； } / *这应该是桌面背景* /

ul {background-color：Window; } / *这是浏览器背景* /