Edit/change template

Hello,
I would like to customize the default templates. The header and footer do not like me so. I also wish to customize the colors of the links. How do I do that? In the css files I found in this nothing?
greeting
Kutsche

I to would like to customize the default template.

But your answer tells me how to remove the default template and replace it with my own template. That is something different.

Or am I missing something?