body{
    background-color: #000;
    color: #FFF;
    font-family: 'Courier New', Courier, monospace;

}
.flex{
    display: flex;
    flex: auto;
}
.flex.across{
    flex-direction: row;
}
.flex.down{
    flex-direction: column;
}
ul.nav{
    list-style-type: none;
}