Hero Image widget not full-width on WordPress theme Twenty Sixteen?

Hi all,

I’ve been scouring the internet for DAYS trying to fix this issue, but does anyone know why the Hero widget won’t reach the edges of my pages? I can’t tell if it’s coming from the plugin/it’s a widget problem, or if it’s a theme problem.
Here’s my site: www.laumi.co
I’ve been using WordPress’s 2016 theme just because 2017 was giving me too many problems, and 2016 seemed simpler and easier to deal with.

I’ve literally pored over my entire css file, added like 4 different versions of custom css that tried to get rid of the padding/margin around the left and right sides of the site (it looks like this on every page) but I can’t seem to figure it out and it’s driving me insane.

Thanks,
Michelle

P.S. Some of the codes people suggested around the web (none of which worked for me):

1)
.no-sidebar .entry-header, .no-sidebar .entry-content, .no-sidebar .entry-summary, .no-sidebar .entry-footer, .no-sidebar .comments-area, .no-sidebar .image-navigation, .no-sidebar .post-navigation, .no-sidebar .pagination, .no-sidebar .page-header, .no-sidebar .page-content, .no-sidebar .content-bottom-widgets {
margin-right: 0px;
margin-left: 0px;
}

2)
#page {
max-width: none;
}

body {
padding: 0;
}

.site-header {
padding: 0 4.5455%;
}