<div style="float:left; border:2px solid black; padding:10px; box-sizing:border-box; height:500px; height:-webkit-min-content; height:-moz-min-content; height:min-content; width:500px; width:-webkit-min-content; width:-moz-min-content; width:min-content">
<div style="width:100px;height:100px;background-color:green"></div>
</div>