.caret-up {
    width: 0; 
    height: 0; 
    border-left: 4px solid rgba(0, 0, 0, 0);
    border-right: 4px solid rgba(0, 0, 0, 0);
    border-bottom: 4px solid;
    
    display: inline-block;
    vertical-align: middle;
}