html - Using display:table-cell without containing display:table

Question

I'm trying to create a semantically correct HTML 5 web page utilizing CSS 3. I've created the below markup which exists at the root of my body element. Applying display:table-cell to both the aside and section elements causes them to column as I would like them to. However, I have no containing element to apply a display:table to. Is it okay to use display:table-cell if the element which it is being applied to is not contained within a display:table? If not is there a better mechanism to create a column layout with these elements without using floats?

<aside>
    <nav>
       <ul>
           <li><a href="#">Link 1</a></li>
           <li><a href="#">Link 2</a></li>
       </ul>
    </nav>
</aside>
<section>
    Content goes here
</section>

Answer 1

Yes, it is valid. Read 17.2.1 of CSS2 spec regarding anonymous table objects. More specifically, these sections...

Generating missing child wrappers:

1. If a child C of a 'table' or 'inline-table' box is not a proper table child, then generate an anonymous 'table-row' box around C and all consecutive siblings of C that are not proper table children.
2. If a child C of a row group box is not a 'table-row' box, then generate an anonymous 'table-row' box around C and all consecutive siblings of C that are not 'table-row' boxes.
3. If a child C of a 'table-row' box is not a 'table-cell', then generate an anonymous 'table-cell' box around C and all consecutive siblings of C that are not 'table-cell' boxes.

Generate missing parents:

1. For each 'table-cell' box C in a sequence of consecutive internal table and 'table-caption' siblings, if C's parent is not a 'table-row' then generate an anonymous 'table-row' box around C and all consecutive siblings of C that are 'table-cell' boxes.

2. For each proper table child C in a sequence of consecutive proper table children, if C is misparented then generate an anonymous 'table' or 'inline-table' box T around C and all consecutive siblings of C that are proper table children. (If C's parent is an 'inline' box, then T must be an 'inline-table' box; otherwise it must be a 'table' box.)

   • A 'table-row' is misparented if its parent is neither a row group box nor a 'table' or 'inline-table' box.
   • A 'table-column' box is misparented if its parent is neither a 'table-column-group' box nor a 'table' or 'inline-table' box.
   • A row group box, 'table-column-group' box, or 'table-caption' box is misparented if its parent is neither a 'table' box nor an 'inline-table' box.