Simplest way to create a theme

Question

I am about to create my first ever WordPress theme, based on the excellent tips provided in this answer.

Initially, all I want to do is to modify the CSS only, changing nothing in the .php or other files.

A straightforward approach is to simply ZIP the entire directory structure of wp-content/themes/twentyeleven, rename it, modify the CSS files only, then upload the entire thing as a new theme.

It should work, but it looks to me as very wasteful, since I am essentially duplicating all theme files for a handful of .css files.

Is there a better way to create a theme that is based on an existing theme (e.g. twentyeleven)?

Answer 1

Great question. You should create a child theme - this allows you to modify only the parts of the parent theme you need to and avoids conflicts when upgrading the theme further down the line (if you're using 2011, watch your dashboard for update notifications).

I would also reccommend you take a look at theme frameworks before you begin.