Help with Custom CSS?

I am working on my webpage but my template puts a white box around my logo. Is there a way to remove this? I know I am supposed to use Custom CSS but I am not sure what the code should look like.

This is what the header.php looks like now (Not sure if this helps at all):

<!-- SITE LOGO -->
		<?php if( of_get_option('site_logo') ): ?>
		<a id="logo" href="<?php echo home_url( '/' ); ?>" title="<?php echo esc_attr( get_bloginfo( 'name', 'display' ) ); ?>">
			<img alt="<?php echo esc_attr( get_bloginfo( 'name', 'display' ) ); ?> logo" src="<?php echo of_get_option('site_logo'); ?>" />
		</a>
		<?php else: ?>
		<a id="logo" class="logo_ph" href="<?php echo home_url( '/' ); ?>" title="<?php echo esc_attr( get_bloginfo( 'name', 'display' ) ); ?>"></a>

Here is a picture of the logo in the white box:

http://www.diigo.com/item/image/23far/7nra
(Click “View Original Size”)

Thank you so much for your help! I really appreciate it.