Costruisci una classe CSS flexbox.
'.flex-container {
    display: flex;
    flex-direction: row; 
    flex-wrap: wrap;
    justify-content: center; 
    align-items: center;
}' si traduce in italiano come:

'.flex-container {
    display: flex;
    flex-direction: riga; 
    flex-wrap: avvolgere;
    justify-content: centro; 
    align-items: centro;
}'