XenForo How to add custom icon in widget?

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How to add custom icon in widget? - Styling and customization questions

.p-body-sidebar [data-widget-id="56"] .block-container
{       
background-image:url("path_to_image");
    padding-top:50px;
    background-size:50px 50px;
    background-position:center top;
    background-repeat:no-repeat;
}

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