Change padding from elements in Blogs MU with Sidebar Login


I was creating a login form in the header, because in my opinion that's the best position for an login form, when I ran into a problem.
First I installed a plugin to create a login form in the widget area, called 'Sidebar Login'. Then I installed the 'Custom Widget Area' plugin, so I could create a widget area in the header. Thereafter I added a line of code into the header.php and changed the regular login form setting from disabled to enabled. Till now it works great!

Now the problem is that the padding from the different elements (e.g. text-input, button, text) is not aligned like I had it in my mind. There's too much space between these elements, as you can see on the screenshot I attached. I've looked at the coding, but I couldn't come up with a solution for this problem. Does anyone of you got an idea how to solve my problem?

I hope it is clear what I mean. It was hard to explain, because English is not my mother tongue.. :wink:

Thanks in advance and kind regards,