What to do when the background disappears on Bootstrap 4?

Question

css

When horizontal scrolling appears in all major browsers, the background color and background images are filled with white. The same happens when displayed horizontally on a mobile phone
It is suspected that the problem is related to bootstrap 4.0
Site: xn--b1asmb7a.xn--p1ai

Answer 1

You don't have adaptability for about 765 to 1200.