Problem with css, please help

Hello, I am new in using wordpress, for now just eperimenting on betasite http://hologram1986.funsite.cz 🙂 But I have some problems with css, I cant solve. So If you will help, I would be very grateful. I tried everything I could, but still without succes. I use template Merlin, but very adapted by colors.

So here it is:

1. How can I remove blank space before head image? I tried every margin and padding, but nothing helped.

2. Somehow I lost arrows in drop menus. I tought that there is only same color like background, but didnt find it. So, how can I restore them?

3. Last one. Where I can edit text like “leave comment” and “comments”?

Thank you very very much:)