Custom Social Media Icon to Top Bar (Using Image)

HI Guys,
I have followed your instructions to add a custom social media icon to this website: https://ionafiredistrict.com/

I’ve added to the functions.php file this code (In my Child Theme) per your instructions, and this part DOES WORK, because “Nextdoor” now appears in Theme Options > Social Profiles > and you can see that I have added the Social Profile for Nextdoor Neighbor and it’s link there:

// Add NextDoor to Social Profiles in Theme Options
function avia_add_custom_social_icon($icons) {
$icons[‘Nextdoor’] = ‘Nextdoor’;
return $icons;
}
add_filter(‘avf_social_icons_options’,’avia_add_custom_social_icon’, 10, 1);

But, it is not appearing in the top bar: should appear to the right of the Youtubr Icon. I have added your custom CSS as well, as follows, but it still does not appear (interestingly, when I used your Kriesi glyph example, a white pencil did appear). This is the CSS I added – I don’t know what is supposed to be in ‘content ” ” ‘ – I tried adding the image there too, but that didn’t work.

#top #wrap_all .av-social-link-Nextdoor a:before{
content: “”;
width: 20px;
height: 20px;
display: inline-block;
vertical-align: middle;
background: url(https://ionafiredistrict.com/wp-content/uploads/2022/02/NDN-Icon.png) no-repeat center center;
background-size: contain;
}

Thank you for your help.