Background Color of Posts

I’m using the Custom Community theme, the free version. I was able to add a code in my custom css to make the background of my posts on the homepage white, as I want the container transparent. How can I replicate this on all pages? Right now if I navigate away from the home page their is no background. The only way I have found to get a white background is to change my container from transparent to white. I do not like the look of that. Any help is appreciated. Thanks. I feel as though I have tried every bit of CSS I can and no change. I really like this theme so if anyone can help me fix this I’d be so grateful.

website: https://feistymom.me