header image size and navigation alignment

Hello all, I am working with this theme and I am not 100 percent sure how it works as I have been going along customizing it so please forgive me if when looking at it some of it does not make sense to you. Please also keep in mind the theme would not let me modify it to do what I wanted so I made the main page (index.php) static by editing the code (it broke the site if I tried to do it through the settings).

It is very confusing for me because I am using the free version of the theme, and when editing the files directly there are a number of editor pages for the header. I am hoping that someone can just tell me what to call the header in the styles.css file to edit it.

I am wondering how to do 2 main things with the header.

1) Change the width and height of the image that is the header

2) Align the navigation menu options so that they are aligned to the bottom below the header image (I am ok with editing the header image to be partially black so that it appears like the text is below the image).

As a bonus question does anyone know why there is a huge space before the text on the front page? (the text is hardcoded on index.php, there is no nbsp before the text or anything and like I said the settings would not allow me to set the front page to static without breaking the entire site)

Any help is greatly appreciated, I have spent quite a bit of time trying to figure out how to manipulate these sections but I am just having no luck.