I think the use of inline styles was simply to make the example more compact and readable than something like: <style> .table-example { display: table; }

I think the use of inline styles was simply to make the example more compact and readable than something like: <style> .table-example { display: table; } .table-example div { display:table-cell; vertical-align:middle; } .table-example div div { margin-left:auto; margin-right:auto; } </style> <div class="table-example"> <div> <div></div> </div> </div>