Add Custom Social Icons to the Theme Options

Hi,

I try to put a new social profile for my website, i put this instructions in fonctions.php

// Add tripadvisor social profile
function avia_add_custom_social_icon($icons) {
$icons[‘Tripadvisor’] = ‘Tripadvisor’;
return $icons;
}
add_filter(‘avf_social_icons_options’,’avia_add_custom_social_icon’, 10, 1);

and i put this following instructions in the quick CSS

#top #wrap_all .av-social-link-kriesi a:before{
content: “”;
width: 20px;
height: 20px;
display: inline-block;
vertical-align: middle;
background: url(http://hydrospeed-ariege.fr/wp-content/themes/enfold/images/Tripadvisor.png) no-repeat center center;
background-size: contain;
}

it doesn’t work
can you help me please.

PS (sorry for my English:)