CSS Flexbox Alignment: justify-content Property 
.content1 {
    display: flex;
    justify-content: flex-start;
}
/* default */

.item1
.item2 



.content2 {
    display: flex;
    justify-content: flex-end;
}

.item1
.item2 



.content3 {
    display: flex;
    justify-content: center;
}

.item1
.item2 



.content4 {
    display: flex;
    justify-content: space-between;
}

.item1
.item2 



.content5 {
    display: flex;
    justify-content: space-around;
}

.item1
.item2 



.content6 {
    display: flex;
    justify-content: space-evenly;
}

.item1
.item2