@Emmelie Brownlee: That cannot be done with custom css. For that you need to build child theme and change the hook position. You can download sample child theme from http://catchthemes.com/blog/create-child-theme-wordpress/
Then you need to unhook the promotion headline and add it before grid content. For example, you can add the following code in your child theme functions.php file.
// Unhook default gridalicious functions, removing promotion headline
function unhook_gridalicious_functions() {
remove_action( 'gridalicious_before_content', 'gridalicious_promotion_headline', 30 );
}
add_action('init','unhook_thematic_functions');
// Adding promotion headline in top of Grid content
add_action( 'gridalicious_before_content', 'gridalicious_promotion_headline', 5 );
.
