When I try to make image transparent in navbar, navbar disappears, how to resolve this issue?

https://demo.w3layouts.com/demos_new/template_demo/28-07-2021/biodata-liberty-demo_Free/2002651968/web/index.html

This is the website that I am trying to build.

Below is what I’ve built so far.

I’m using bootstrap. The navbar class is “navbar”.

I put this into css:

.navbar {

opacity: 0.8;

}

But I’m not getting expected output. Please help me get expected output.

fixed.

.navbar {
  background-color: rgba(0, 0, 0, 0) !important;
}