Try to add another div inside the "menu" and make it bigger than 100% width and height. Then turn it by using Transforms and move it, using absolute aligning so it would feel all "menu". Sure do not forget to make menu averflow: hidden and change its interaction to display:block - display: none (instead of sliding up and down).
Then use one more trigger in hamburfer menu interaction which will move this new div into the correct position and hide again. It is not always easy but, after couple minutes of experiment you can find correct position.
Here is a video, I tried to play with tthe menu and colorblock on your site. Hope it will be useful: https://youtu.be/dp7scch2RFY