How can I change the style of the standard form

If I produce a screencast, the forms which are used are automatically in a dark blue colour. How can I change it to light blue for all automatically inserting forms? It`s the special colour of my company design. 

In the moment I change it for any single object on every form and I get crazy about that! Also if I insert a form, it`s always the dark blue, I`ve already tried some options, but nothing helps!