Using content type fields within page.html.twig I am new to Drupal 8, and relatively new to Drupal templating in general.

Here's what I am trying to do:
I have a content type, called "Property" with a "header_color" field.  When I add a property, I set the color that I want for that property's header.
When I then navigate to that node, the background color of the page's header would be whatever I set the color to.

My understanding is that this needs to take place in page.html.twig, and that there is a way to grab the data from the content type and use it within page.html.twig, using: 

{{ node.field_header_color.value }}. 

This is the tag I have in my page.html.twig:

&lt;header id="header" class="header" role="banner" aria-label="{{ 'Site header'|t }}" style='background-color:{{ node.field_header_color.value }}'&gt;


When I inspect it in the Chrome Dev, it shows: 

"style='background-color:''"

Can someone give me some guidance on what I am doing wrong here?

I am using Drupal 8.6.4
In the preprocess_page set up the variable 

if (($node = \Drupal::routeMatch()-&gt;getParameter('node')) &amp;&amp; $node instanceof \Drupal\node\NodeInterface) {
 $variables['bg_color'] = $node-&gt;field_header_color-&gt;value;      


}
     and use this in ur twig file

&lt;header id="header" class="header" role="banner" aria-label="{{ 'Site header'|t }}" style='background-color:{{bg_color}}'&gt;