Hello,
Where have you added the code?
http://prntscr.com/n6xw2o
Please add this code in Theme Options > Custom css > Global custom CSS:
.product-view-mask2 .footer-product .by-vendor-name-link:before {
content: "\e1000";
font-family: 'xstore-icons';
color: white;
font-size: 14px;
}
.product-view-mask2 .footer-product .by-vendor-name-link {
font-size: 0;
}
.product-view-mask2 .footer-product .by-vendor-name-link:hover,
.product-view-mask2 .footer-product .by-vendor-name-link:hover {
background: #333333;
}
.product-view-mask2 .footer-product .by-vendor-name-link,
.product-view-mask2 .footer-product .by-vendor-name-link {
font-size: 0;
padding: 5px 0;
}
.etheme_products .product-view-mask2 .footer-product .pre_order_loop,
.products-slider .product-view-mask2 .footer-product .pre_order_loop {
font-size: 0;
padding: 8px 0;
}
.etheme_products .product-view-mask2 .footer-product .pre_order_loop:hover,
.products-slider .product-view-mask2 .footer-product .pre_order_loop:hover {
background: #333333;
}
.etheme_products .product-view-mask2 .footer-product .pre_order_loop:before,
.products-slider .product-view-mask2 .footer-product .pre_order_loop:before {
content: "\f23d";
font-family: FontAwesome;
color: white;
font-size: 14px;
}
.etheme_products .product-view-mask2 .footer-product,
.products-slider .product-view-mask2 .footer-product {
bottom: 0rem;
}
Clear cache before checking the result.
Regards