Shrink pictures proportionately to the screen

Hey guys,

You were all super awesome for an earlier question I had. Hopefully you can help here too!

I’m trying to create a landing page https://www.inspiritfinancial.com/welcome to model another great landing page I saw https://www.videofruit.com. I love how the pictures resize and the logo doesn’t stay too big on mobile.

Can someone help me change my page so that it maintains a similar aspect ratio. The main effort is to make my site more mobile friendly.

I have zero css experience so please break the answer down for me ??

Thanks guys. You rock!