.bb {
    display: inline-block;
    position: relative;
    text-decoration: none;
    text-align: center;
}

.bb:hover:before {
    content: '';
    width: 100%;
    height: 7%;
    position: absolute;
    left: 0;
    bottom: 0;
    box-shadow: inset 0 -10px 0 #0a58cae1;
}