CSS – Can’t get custom header to show on all pages

I have added the below code into my Additional CSS, but the header image is only showing on my homepage. The previous header image has disappeared and now only the color (#282D31) is showing in the header on all other pages. How do I get the image to appear on all of my pages?

#masthead {
background: #282D31 url(‘wp-content/uploads/2018/10/border57-3.png’) no-repeat center center;
background-size: cover;
color: #FFFFFF;
left: 0;
top: 0;
width: 100%;
z-index: 5; }

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