As soon as you have a fixed height and content overflows, the overflow directive will kick in, if you set it to auto, it will show scrollbars. So to not have scrollbars on the inner div, you need to remove the fixed height on the box1 class and rather set it on the outer div, box

    .box {
      overflow: auto;
height: 290px;
border: 1px solid #383737;
margin-bottom: 30px;
background-color: #3d3d3d;
    }

    .box1 {
overflow: auto;
    }