To render items in three columns, I attempted to add the following CSS3 directives to my project's README.md file, but the styling was stripped out:
<div style="-webkit-column-count: 3; -moz-column-count: 3; column-count: 3; -webkit-column-rule: 1px dotted #e0e0e0; -moz-column-rule: 1px dotted #e0e0e0; column-rule: 1px dotted #e0e0e0;">
    <div style="display: inline-block;">
        <!-- first column's content -->
    </div>
    <div style="display: inline-block;">
        <!-- second column's content -->
    </div>
    <div style="display: inline-block;">
        <!-- third column's content -->
    </div>
</div>
This styling works correctly outside of GitHub's processing of Markdown. How can I put data into multiple columns in a Markdown document? Note that I am not concerned about support for IE browsers and don't care if IE renders a single column (my software project does not work on Windows clients, anyway).