.expandir
{
    max-width: 300px;
    overflow: hidden;
    text-overflow: ellipsis;
    white-space: nowrap;
    transition: width 0.3s ease-in-out;
    -webkit-transition: width 0.3s ease-in-out;
}

.expandir:hover{
    overflow: auto;
    text-overflow: ellipsis;
    white-space: initial;
}