Can I custom original design using WPMU Dixi?

Hi!

I want to custom your WPMU Dixi Theme.
Because my original design has 3 columns,So similar to WPMU Dixi.

But When I saw your style.css, "All styles and js scripts are now loaded in wp_print_style() and wp_enqueue_scripts() in functions.php" was found.

So, I can't find out your original css style.
I want to change your css directly,Is that possible?or should I use the other theme which you recommend for me?

Thanks from Japan.
Koji