Custom boxes not full width on smaller devices



I have three custom boxes at the top of my page (the purple headers). When viewed on a smaller device, they drop onto each other (which is correct) but they aren’t being centred and covering the full width of the page (see “decision making”).
Do you have any ideas how to fix this, please? I’d much rather keep them as boxes instead of animated boxes.



Here is my website, the issue is on the front page