table.widefat {
    border: 1px solid #ccc; /* Adds a border to the entire table */
    border-collapse: collapse;
}

table.widefat th,
table.widefat td {
    border: 1px solid #ccc; /* Adds a border to each table header and cell */
    padding: 8px; /* Adds space inside the cells */
    text-align: left;
}