I’m using the defauly Jekyll sytax highlighter that works well, until it doesn’t. Reminder that language tags are CASE SENSTIVE!

```html
<div>good sample</div>
```
and NOT:

```HTML
<div>bad sample</div>
```

All sorts of things seem to go wrong when the language spec, in the above example HTML is not lower case.

Thanks Dan Vega for the tip on How to escape a backtic within a code block in markdown:

“The first solution to our problem is to use more backticks. You will need to place 4 of them around your code block that contains 3.”

Next, when using mardown md files, note that the liquid include code_header.html needs to be manually included. It is missing above, and present below:

{% include code_header.html %}
```html
<div>good sample</div>
```

My copy-to-clipboard feature was implemented with thanks once again toAleksandr Hovhannisyan for his How to Add a Copy-to-Clipboard Button to Jekyll blog.