How to Style the Domain Search Bar with CSS

The HTML structure makes it easy to style one or more domain search bars. Each widget is wrapped in a div that has a unique ID assigned by WordPress in addition to a class shared by all instances of the widget. For your convenience the ID is displayed at the top of the widget options. Example CSS selectors you might use:

#wpdnsearch-1 {}
#wpdnsearch-1 .wp_dn_form {}
#wpdnsearch-1 select[name='tld'] {}
#wpdnsearch-1 input[name='submit'] {}

The selectors above would only apply to the first instance of the WordPress Domain Search widget, as indicated by the 1 (one) that WordPress assigned to it. To apply the same CSS to all instances of the WordPress Domain Search widget you would use the class on the wrapper div instead of the unique ID, like so:

.wp_domain_search {}
.wp_domain_search .wp_dn_form {}
.wp_domain_search select[name='tld'] {}
.wp_domain_search input[name='submit'] {}

There are many other combinations of IDs, classes, and elements that can be used to style your domain search bars. These are only a few simple examples.

http://wordpress.org/extend/plugins/wordpress-domain-search/