Removing logo, changing colors on Pixel Blogging 1.7 theme

I really like the look of this theme, but I would really like to remove the double circle logo at the top left. I would also like to change the colors in the back ground. It fades from black to a purple. I like that the colors fade, I would just like to change which colors they are. I am working on learning HTML and then CSS, but for now I am beginner and am still getting used to a lot of the terms. I would really appreciate any help with this.