difficult responsive layout, using upfront

I am currently working at a difficult responsive layout.
It has a sticky header (logo left + menu right)
It has a left side menu and a content box at the right part that has a rounded border and is fixed. It should have auto scrollbox.
Lastly there is a footer section with social buttons left and another menu at the right.
All sounds easy, but there is a fixed background with triangulars and sifferent colors.
I have attached a screenshot to explain.
Any ideas how to go about it?
I started with spirit and created the sections but I cannot fixe the backgrounds.