table {
    margin: 0 auto;
    width: 100%;
}

#book tbody {
    margin: 0 auto;
}

#book td, #book th {
    padding: 8px;
    width: 50%;
}

#book tr:nth-child(even){background-color: #f2f2f2;}

#book tr:hover {background-color: #ddd;}

#book th {
    padding-top: 12px;
    padding-bottom: 12px;
    text-align: left;
    background-color: #4CAF50;
    color: white;
}