how do I to change the login form appearance?

Hi there.

the issue is that I'd like to change the position and appearance of the login box. My intention is to put the login form upstairs the site as in this picture:

As you can see I could move the form to upstairs area. But now it has a very bad aspect. I'd like to get some appearance as in this image:

In the image you can see two squares: one red with the number 1 and one blue with the number 2.

I want to remove the login form number 2 in red and get some similar to number 1 in blue.

For to do this I've tryed many combinations of css but it seems the css code is blocked for the form...

Aas you can see I'd like to change the width of the inputs and the positions...

Could you help me?

thanks, Emilio