Some Div are fading

I’m working on to build my website, for some reason I didn’t succeed to demystify there’s some div in my home page started fading away when I opened the builder.
1- Any suggestion to resolve this problem?
2- another question regarding the nav bar, is it inside the body or outside and upper the body?
3- Is it possible to copy some div or section between different projects?
Best Regards!

In case you’re asking about my domain

Hi, I fixed problem with divs for you.

  1. Issue was that you have set fixed body height to 200px, so everything below 200px was bugged.
  2. Everything is always inside of body.
  3. Check video on how to copy sections between projects.
  4. I fixed a form you tried to embed. Check last 2 mins of video

thanks @Pakic, you’re very generous in your explanation. Very helpful. remain the form customization it will be very helpful to give me a hand. coz the form is well formatted but when I insert it as html it becomes in complete desorder!