Full background image instead of solid colour?

Site URL: https://sarah-ward-interiors.squarespace.com

Hello,

I'm wondering if it's possible to add a background image to the Wells template, rather than just using a solid colour? 

https://sarah-ward-interiors.squarespace.com

Password: SWI2020

Thanks, Sarah

Add to Home > Design > Custom CSS

div#canvas {
    background-image: url(https://beaverhero.com/wp-content/uploads/2020/05/2-websites-same-subscription-min.png);
    background-repeat: no-repeat;
    background-size: cover;
}

Replace with your image url