.wp-block-button {
 
    &.is-style-external {
        .wp-block-button__link {
            &::after{
            content: "";            
            flex-shrink: 0;         
            width: 20px;            
            height: 20px;           
            background: url("../../../img/ico-ar-tr-20.svg") no-repeat center;
            background-size: contain; 
            }
        }
    }
}