Inserting Background Image in Header

Hello,

Here is the website: https://www.coveragenewstv.com/

Currently, there are 12 different header styles in the theme, I’ve chosen “Style 1” and its code in style.css is here:
https://github.com/waseem3302/coveragenewstv/blob/master/style.css

I can’t figure out on how to put a full width and full height background image in the whole header only.

I tried adding some css at the bottom on style.css:

.td-banner-wrap-full, .td-header-menu-wrap-full {
    background-color: transparent;
}

.td-header-wrap.td-header-style-1 {
    background-image: url(https://www.coveragenewstv.com/wp-content/uploads/2016/02/header-image.jpg);
    background-size: cover;
}

Unfortunately it’s not working, can you please help me out, I’m new to coding.

Thank you!