CSS: cascade

You can use more than one style sheet in you HTML document. In fact more style sheets can influence your page at the same time. However you have to knows rules used whenever there are conflicts between style sheets:

The author's style sheets override the reader's style sheet (the reader is the page's visitor)
Rules used in style sheet override rules in imported style sheets
more specific tags (selectors) override more general ones
Whenever 2 rules have the same weight, the latter override the previous

However ther is a notation by means of which one can override rules:

!important

In fact, if 2 rules have the same weight, the rule marked with '!important' wins.