CSS Classes in Pure Markdown

One of Markdowns design choices is to not implement any layout.

Problem

One thing I wish it had would be a way of specifying image positions. E.g.: float on right and have width equal to the third of the column. Just like the example illustration somewhere next to this text.

Markdown does support plain html tags, so a verbatim <img> tag would be a solution. I find this inelegant, however. Various markdown processors support their own way to add classes, or have their own layout engine. As I prefer to keep my markdown as close to the GitHub style as possible, this is not an option for me.

Solution

I have already explored the use of the $= selector for the src attribute in my previous article.

Now let us take this approach a bit further. We declare the CSS like this:

img[src*="+right"] {
  float: right;
  margin-left: 20px;
}
    
img[src*="+third"] {
  width: 30%;
}

This allows us to add classes in markdown inside location hashes.

The following image will be floating on the right.

![illustration]

[illustration]: http://example.com/illustration.png#+right+third

And that is all there is to it.