How to make my background image PERMANENT!

Hi Everyone,

I think this is a pretty easy question for those experienced in CSS. I created my own backgound image and I have it implemented on my site but I want to have it stay exactly where it is for those who do not share the same display settings I have…

For example when someone visits my site sometimes the sidebar and content bleed into each other if they are not running the high 1368 x 766 display settings I’m using, or if they don’t have a widescreen monitor?

So is there any way I can have the background adapt to a viewers settings and therefore the blog would look the same to anyone?

the site is https://aerialnoise.com/

I’m still trying to get my feet wet in css so any help would be appreciative