Как отцентрировать флекс элементы?

<div class="container">
  <div class="first"></div>
  <div class="second"></div>
  <div class="third"></div>
</div>

.first , .second, .third {
  width: 100px;
  height: 100px;
  border: 3px solid red;
  margin-left: 10px;
}

.container {
  display: flex;
  justify-content: center;
  position: relative;
}

.third {
  position: absolute;
  right: 0;
}