Unable to make header expand to full page width

Hello,
I’m a beginner with using webflow, and for the life of me I am unable to make the headers on this site expand to the full page width. On another note, how would I go about replacing the black backgrounds with pictures?


Here is my site Read-Only: Webflow - Caelus Actual

Just another question I had, to save creating another thread, the dropdown on the navbar for mobile sites color is the same as the text color. How do I change the dropdown color?
Screenshot:

Hi

Please check section div spacing

make this 30 to 0 both side

also always section main div is 100vw

For hamburger menu go to designer mode select tab view from top

Then left side check menu button div selected & right side open the menu
Now you can change the setting for individual div as you want.

Let me know if you have any questions.