How to switch CSS loading according to the time of day you visit the site

About CSS deciding on the appearance of the page Various designs have been considered at every and every place so far, but this time is to change that CSS according to the time of day. In the morning it seems like morning CSS, in the evening if you use CSS at night, various applications seems to be useful.

Details are as follows.
Katgal.com: New and Improved

Here is another idea that extends this idea further.

Nicholasjon.com :: Time Sensitive {1/14/2007}

On the above site I propose that it will be fun as well as time depending on the weather as follows.

Sunny


Cloudiness


Night