body {
    margin: 0 auto;
    padding: 0;
    border: 0;
    min-width: 660px;
    max-width: 60em;
}

.row_wrapper {
    display: flex;
    flex-direction: row;
}

.head-foot {
    padding: 10px;
    text-align: center;
    background-color: sienna;
    color: white;
}

.content {
    flex: 1;
    padding: 10px;
}

.mainnav {
    flex: 0 0 160px;
    padding: 10px;
    border-left: 1px solid black;
    border-right: 1px solid black;
    background: sandybrown;
}

.sidebar {
    flex: 0 0 210px;
    padding: 10px;
    border-left: 1px solid black;
    border-right: 1px solid black;
    background: peachpuff;
}