Change a background image on a page

I’m attempting to change the background image on this page:
https://www.crunchyfrugalista.com/test-2/

I’ve tried adding a few different rules to style.css in the Editor:

.magazine-landing-wide .full-width-content #content-sidebar-wrap {
	width: 1010px;  background: url(https://www.crunchyfrugalista.com/wp-content/uploads/2013/11/crunchy-background-wide.jpg);
}

.page.page-id-23978.page-template.page-template-page_landing-php.custom-background.custom-header.header-image.full-width-content.magazine-teal.magazine-landing-wide.magazine-landing-wide #wrap #inner .wrap #content-sidebar-wrap #content {
	width: 1010px;  background: none;

[please mark any posted code – https://codex.www.ads-software.com/Forum_Welcome#Posting_Code ]

Anything I’ve tried doesn’t seem to be affecting #content-sidebar-wrap. Any ideas?