Why CSS File Do I Change?

In 2.0, do I edit the styles.css or styles.base.css file? Why 2 css files like this and what is the result of editing each (since they share a lot of the same styles)?

Here is a good explanation:



[URL=“http://forum.cs-cart.com/showthread.php?t=10497&highlight=styles.css+styles.base.css”]http://forum.cs-cart.com/showthread.php?t=10497&highlight=styles.css+styles.base.css[/URL]