title: Specifying hexadecimal colour in RMarkdown YAML header
body: <p>I have the following RMarkdown file:</p>
  
  <pre><code>---
  title: "Test"
  author: "Mr. Test"
  date: "September 5, 2018"
  output: pdf_document
  urlcolor: red
  ---
  
  [URL](www.google.com)
  </code></pre>
  
  <p>This produces the following:</p>
  
  <p><a href="https://i.stack.imgur.com/AKDTZ.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/AKDTZ.png" alt="enter image description here"></a></p>
  
  <p>The red link leads to www.google.com, as expected. Awesome. Now, say I wanted my URLs to be a nameless hexadecimal colour, say, <code>#FF3300</code>. I have tried various approaches to providing this colour without success. For example, <code>#FF3300</code> is ignored as it is interpreted as a comment; <code>"#FF3300"</code> throws an error, as does <code>"0xFF3300"</code> and <code>0xFF3300</code>. So, my question: what is the correct syntax when specifying hexadecimal colours in a YAML header?</p>