How can I change the background of my debut theme website?

Store Design
1

For some reason i am unable to find and remove the background for my website www.chinakwe.com, i use a debut theme.
I even tried to use this code:

#PageContainer {
background-position: center center;
background-image: url(https://cdn.shopify.com/s/files/1/0528/9223/7979/t/1/assets/chinakwe-bg.png?v=1665754129);
background-repeat: no-repeat;
}

Nothing changed. Can you guys help?

2

Which background and where specifically? That code adds an image background.

3

Thanks for your response…

Basically i am trying to change the page content background from what is currently there to this: https://cdn.shopify.com/s/files/1/0528/9223/7979/t/1/assets/chinakwe-bg.png?

I saw the above code online, i used in in my theme.css but it didn’t work so i am seeking a better solution. Thanks.