section
.flexcontainer
    {
        display:flex;
        flex-direction: row;
    }
    style
    .flex-container {
      display: flex;
      flex-direction: column;
      background-color: DodgerBlue;
    }
    
    .flex-container > div {
      background-color: #f1f1f1;
      width: 100px;
      margin: 10px;
      text-align: center;
      line-height: 75px;
      font-size: 30px;
    }