center content in screen flex code example

Example 1: center image inside flexbox

.box {
  display: flex;
  align-items: center;
  justify-content: center;
}

.box img {
  width: 100px;
  height: 100px;
}

<div class="box">
  <img>
</div>

Example 2: how center content in css by using flex

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