.center {
    text-align: center;
}

.left {
    text-align: left;
}

.bold {
    font-weight: bold;
}

table {
    width: 75%;
}

table, tr, th, td {
    border: 1px solid black;
    border-collapse: collapse;
}

th {
    text-align: center;
    background-color: #d9d9d9;
    height: 26px;
}

td {
    padding: 2px 5px;
}

caption {
    text-align: center;
    background-color: #d9d9d9;
    font-weight: bold;
    border: 1px solid black;
}

.half {
    width: 50%;
    margin-left: auto;
    margin-right: auto;
}