Using CSS :before and :after pseudo-elements with inline CSS?

I'm making an HTML email signature with inline CSS (i.e. CSS in style attributes), and I am curious as to whether it's possible to use the :before and :after pseudo-elements.

If so, how would I implement something like this with inline CSS?

td { text-align: justify; }
td:after { content: ""; display: inline-block; width: 100%; }

You can't specify inline styles for pseudo-elements.

This is because pseudo-elements, like pseudo-classes (see my answer to this other question), are defined in CSS using selectors as abstractions of the document tree that can't be expressed in HTML. An inline style attribute, on the other hand, is specified within HTML for a particular element.

Since inline styles can only occur in HTML, they will only apply to the HTML element that they're defined on, and not to any pseudo-elements it generates.

As an aside, the main difference between pseudo-elements and pseudo-classes in this aspect is that properties that are inherited by default will be inherited by :before and :after from the generating element, whereas pseudo-class styles just don't apply at all. In your case, for example, if you place text-align: justify in an inline style attribute for a td element, it will be inherited by td:after. The caveat is that you can't declare td:after with the inline style attribute; you must do it in the stylesheet.

as mentioned above: its not possible to call a css pseudo-class / -element inline. what i now did, is: give your element a unique identifier, f.ex. an id or a unique class. and write a fitting <style> element

<style>#id29:before { content: "*";}</style>
<article id="id29">
  <!-- something -->
</article>

fugly, but what inline css isnt..?

You can use the data in inline

 <style>   
 td { text-align: justify; }
 td:after { content: attr(data-content); display: inline-block; width: 100%; }
</style>

<table><tr><td data-content="post"></td></tr></table>