It's actually a Steemit-exclusive trick (I think) that involves using the pull-right class. Enclose the text you want to right align inside a div that uses the class pull-right. I've detailed an example below:

<div class="pull-right">
Chapter Y >> <em>(Coming next week)</em>
</div>

Make sure to place that div before the text that you want to retain on the left side. There's also a pull-left class, which isn't that extraordinary. Try playing around with it using images, etc :D