MediaWiki:Style.css

.navbox {
    border: 1px solid #aaa;
    width: 100%;
    margin: auto;
    clear: both;
    font-size: 88%;
    text-align: center;
    padding: 1px;
}

tbody {
    display: table-row-group;
    vertical-align: middle;
    border-color: inherit;
}

tr {
    display: table-row;
    vertical-align: inherit;
    border-color: inherit;
}

table.navbox th {
    text-align: center;
    padding-left: 1em;
    padding-right: 1em;
    background: #ccccff;
}