* {
    margin: 0;
    padding: 0;
}

header {
    width: 100vw;
    height: 10vh;
    display: flex;
    justify-content: center;
    align-items: flex-end;
    background-color: black;
    color: whitesmoke;
    font: italic 2em arial;

}
main{
    display: flex;
    justify-content: center;
    align-items: center;
    flex-wrap: wrap;
    width: 100vw;
    height: 100vh;
    background-color: black;

}

main>div{
    display: flex;
    justify-content: center;
    align-items: center;
    margin: 20px;
    width: 150px;
    height: 150px;
    box-shadow: 0 0 10px blue;
}