style.css

<style>
    .fa-quickpanel:before {
        content: "";
        display: inline-block;
        width: 1em;
        height: 1em;
        background-image: url('https://raw.githubusercontent.com/AmitDas4321/Quickpanel/848ff4d118dc0b4131094a56f378bd2bb2e47be0/favicon.svg');
        background-size: contain;
        background-repeat: no-repeat;
        background-position: center;
        vertical-align: middle;
    }
    .fa-quickpanel {
        display: inline-block;
        width: 1em;
        height: 1em;
    }
</style>