Special Header Background colors

Greeting,
I am wondering if you have any solutions for this issue, I am using the special header, this one have white text and logo and a transparent bg color, I had been trying to change the color for something more darker once you start scrolling in the sticky header, but the options in the general settings are not working, neither a code I found in other posts:

.hb-special-header-style #main-wrapper #header-inner.stuck #header-inner-bg {
background: rgba(255, 255, 255, 0) !important;
}

Any clues where I could make this changes, thanks.