Background color appears halfway down the about me section on the homepage

Hi there,

On the homepage of tudietaeslaclave.com there is a background that appears midway through the "about me" section (see here: https://prnt.sc/uidlo0). Notice how it goes from white to another background color.

Do you know how to fix this?

Also, when I am trying to edit the homepage, the only two available options I see for editing are the visual and HTML editor (see here: https://prnt.sc/uidnsc). Is there a plugin that I am missing to be able to edit the various sections of the homepage dynamically?

Thank you so much!