First "class" line of Remark.js renders as paragraph

Hello! I’m adding Remark.js presentation capability into my theme. I’m starting with the boilerplate Remark.js single template. The single.html contains the following code:

<!DOCTYPE html>

    <meta charset="utf-8">
        <!-- The basic CSS that the boilerplate gives -->
    <script src="">

    <textarea id="source">
        {{ .RawContent }}
        var slideshow = remark.create();


And here’s the code I have in my test presentation markdown

title: Basics of PowerShell

class: center, middle

# Basics of Windows PowerShell

The Console is your friend


I see that ‘class: center, middle’ appears in the presentation output. Instead, it should be read by Remark and the H1 should be rendered at the page’s middle-center.

What’s interesting is that the subsequent class instructions are rendered fine; just the very first one isn’t.

Could you please point out the mistake I’m making here?

Here is a screenshot of the rendered output: