How should I choose the accents for Mahapps Metro

Question

I am looking at creating custom Accents for the Mahapps Metro. I see in the link Creating Custom Accents and Themes the following;

<!--ACCENT COLORS-->
<Color x:Key="HighlightColor">#FF9F0055</Color>

<!--80%-->
<Color x:Key="AccentColor">#CCD80073</Color>
<!--60%-->
<Color x:Key="AccentColor2">#99D80073</Color>
<!--40%-->
<Color x:Key="AccentColor3">#66D80073</Color>
<!--20%-->
<Color x:Key="AccentColor4">#33D80073</Color>

The AccentColor has a comment of 80%. What does that mean? 80% of what?

Or for example if my HighlightColor is #FF004E9B what would be the 80% color of this?

Answer 1

After asking the question the only thing I could find on this was this answer on creating a full resource accent/color.

In this example the only thing that is changed is the alpha channel of the ARGB.

Color.FromArgb((byte)(204), originalColor.R, originalColor.G, originalColor.B)

This would be the first accent Color or 80%.