Sticky Navigation Bar Transparent to Solid Background Color When Scrolling Down

Site URL: https://www.tlwchurch.com/

Hello,

I'm trying to make a sticky navigation bar. So I want my navigation bar to be transparent that bleeds into the first picture in the home page and then it becomes solid background color once it scrolls down, sticking to the top of the page.

I've tried this code:
 

.Header.Header--top  {
    position: fixed;
    position: -webkit-sticky;
    top: 0px;
    z-index: 1000;
    width: 100%; 
}

But it hasn't work to get a sticky navigation bar. Maybe my ID or class name is different, but I'm not too sure.

Help is greatly appreciated! Thank you!

Hi,

What is access passwod?