How to create multiple elements when layout?

Question

Layout

Good time of the day, I really need the advice of fierce typesetters, I'm new to this topic, don't hit me hard on the hat :) The bottom line is this. The template has the following image as a background . It occupies 2 blocks horizontally, when adapted for mobile phones, the blocks line up vertically on top of each other, stretching the height of the parent container. As a result, we get such a tricky little thing.
How can I make it up so that the blocks merge during adaptation, so that there is no this white gap? Tried svg, also position: absolute; did not help. By the way, it is possible to use each line separately.