how to center in flexbox code example

Example 1: css flex center

display: flex;
align-items: center;
justify-content: center;

Example 2: centering with flexbox

/* HORIZONTAL */
justify-content: center;

/* VERTICAL */
align-items: center;

Example 3: flexbox align right and left

.primary-nav {
    display:-webkit-flex;
    display:flex;
    list-style-type:none;
    padding:0;
    justify-content:flex-end;
}

.left {
    margin-right:auto;
}

Example 4: how center content in css by using flex

display: flex;
    width: 60%;
    justify-content: center;
    margin: 0 auto;