Responsive Landing Web Page with HTML + CSS

Hey yoh 🙂, I'm new to web designing & still getting used to it. I've created my first NEWBIE-Free challenge, the Huddle Landing Page with 90% accuracy ( I think ) but I was unable to set the background image ( desktop & mobile svg_s ) sizes that fit into the given parameters. Anyhow If I change width, height, or both properties according to my screen view - the background svg_s either span out or stretched. later I tried some CSS solutions but nothing comes out helpful. All I want to know how to set the background svg_s as the same as in the website pre-preview images that were given.

~Thanks~