What is ".foo{}" in the beginning of a stylesheet?

I would like t开发者_开发技巧o know what is the meaning of ".foo{}"

It is placed at the beginning of a css stylesheet i have been modifying.

It's just a CSS block modifying the class foo.

So, every tag in the HTML file with class="foo" would be affected by that CSS block, which in your case does nothing, with what you posted.

all elements with the foo class have the style between the curly brackets after that (none)

Applies style to any HTML element with class "foo".

HTH.