Looks pretty good but personally I would take the gray background from behind the login box & password boxes. Looks kinda funny when you are a guest and not logged in.
Do a search in your templates for "logindetails". Once you asses the info you can find the stylevars for it. I do not know the exact one. I think if I remember correctly that the background is related to another stylevars, so you may need to change the actual css template instead.
There is a neat little tool if you use firefox called Firebug. Its a free add-on that helps you find what the css tag is for an item.
Same here. Check the templates sometimes (not all the time), but sometimes you can make a change in a css template for that particular area that you cannot do in the stylevars.