Black out on automatic numbering

Sometimes, when using the automatic numbering you will find that when you open the document, some or all parts of the numbering are blacked out (see below).

This shows not only in the numbering, but also in the "Styles" ribbon.  Note how on the "Styles" ribbon, "Heading 1" has been affected - there is no number in front of the text in contrast to "Heading 2".

This is easily resolved.  Select the “Design” tab, at the top and underlined in blue below.

On the "Design" tab, select the original style - here it is "Segoe UI".  As you move your cursor over the Style, you should see the numbering restore (see above).  Click on it to apply it.   You may need to adjust the formatting on Heading 1 to bring it back into alignment (see final section below).

If this does not work you may need to go into the "Themes" dropdown menu on the far left and select "Reset to Theme from Template" (see opposite) and then try again. 

To reset the first heading so it is back in line,