As far as I know Jekyll markdown processor adds this HTML around inline code: <code class="highlighter-rouge">code example</code> (assuming you're using rouge).
For code blocks with ```language-name, you get spans which you can style like this:
<div class="language-coffeescript highlighter-rouge"><pre class="highlight"><code><span class="na">paginate_multiple</span><span class="o">:</span><span class="o">-</span><span class="na">paginate</span><span class="o">:</span><span class="mi">3</span></code></pre></div>Single ` marks for inline code doesn't output the spans with classes so it can't be styled.
