.flex
{
    display: flex;
}
.flex-center
{
    justify-content: center;
    align-items: center;
}
.flex-left
{
    justify-content: flex-start;
    align-items: center;
}
.flex-right
{
    justify-content: flex-end;
    align-items: center;
}
.flex-start-start
{
    justify-content: flex-start;
    align-items:  flex-start;
}