This feature is useful if you need to document code. This theme supports code blocks the same way as Kirby always has, using three ` marks before and after, but it also enhances the display of those code blocks using highlight.js.

Here's what it looks like with the default theme included ("railscasts"):

.a-class-name {
  margin: 0;
  padding: 0;
}

#something{
  color:red;
}

If you want to change the color scheme, highlight.js has quite a number of options, any of which can be downloaded and put into /assets/scss/highlightjs/, change the extension to .scss and and then reference from /assets/scss/main.scss.