Manage Landing Page using html, css and Js

Hello everyone, I need as much as possible finishing this challenge. My biggest issues right now are:

1. Background: I can't get the SVGs to show when I use background property on the body tag. I have poured over many solutions on the web but none has helped. PLEASE HELP.
2. The Slider: I used html and CSS to make the slider for mobile screens but I can't seem to get it to the intended state for bigger screens. Any help on this would be mightily appreciated.
3. The little form validation in the footer has ben doing my head in all day. If anyone could check my script and tell what I'm doing wrong, I would be very glad.

If you find anything else wrong with what I have done so far, please let me know. Thank you!!