Full-width images

Site URL: https://www.st-bede.com/

I'm struggling to find a way to make the main image on our home page stretch full width. The prior website developer is no longer with the company and I can't figure out what CSS coding he used (there's a LOT of Custom CSS on the site and I can't make heads-or-tails of what goes to what since very few are labeled what it's for) to make the background styling on the template no longer active nor how to adjust the sizing of the image blocks so they are full-width. 

Add to Design > Custom CSS

/* fullwidth main image */
@media screen and (min-width:901px) {
body.homepage section#content {
    margin-left: 0 !important;
    margin-right: 0 !important;
}
body.homepage {
    overflow-x: hidden;
}
div#page-5f4ff3bfadbea84aa5e70325>.row>.span-12>*:not(:first-child) {
    margin-left: 10vw;
    margin-right: 10vw;
}
}

You are amazing! Thank you - this makes the page look so much better!