Changing 300px to 100% doesn’t do it.
https://jsfiddle.net/k1cg9v4z/7/
div {
width: 100%;
height: 300px;
background-color: #000000;
background-image: url("data:image/svg+xml,%3Csvg width='42' height='44' viewBox='0 0 42 44' xmlns='http://www.w3.org/2000/svg'%3E%3Cg id='Page-1' fill='none' fill-rule='evenodd'%3E%3Cg id='brick-wall' fill='%230110fe' fill-opacity='1'%3E%3Cpath d='M0 0h42v44H0V0zm1 1h40v20H1V1zM0 23h20v20H0V23zm22 0h20v20H22V23z'/%3E%3C/g%3E%3C/g%3E%3C/svg%3E");
}