[css-color-5] Fix bikeshed fatal error.

Author: dbaron

css-color-5/Overview.bs

@@ -121,12 +121,12 @@ in a linear-light-intensity space.
 Arguments are normalized as follows:
 
 1. When a percentage is specified without any [=color-adjuster=]s,
-it is expanded to all adjusters available for the given [=colorspace=] plus alpha.
+	it is expanded to all adjusters available for the given [=colorspace=] plus alpha.
 2. If a percentage is omitted and there are no adjusters present on any color arguments,
-it defaults to 50% (an equal mix of the two colors).
+	it defaults to 50% (an equal mix of the two colors).
 3. Adjusters that are not present on a color default to 0% (i.e. the corresponding components are taken from the other color).
 4. Adjusters that are only present on one of the colors default to <code>100% - <i>p</i></code> on the second color,
-where <i>p</i> is the percentage of the corresponding adjuster in the other color.
+	where <i>p</i> is the percentage of the corresponding adjuster in the other color.
 5. If the sum of corresponding adjusters across all colors is not 100%, percentages are scaled proportionally so that the sum is exactly 100%.
 
 Issue: Do missing adjusters default to 0% everywhere, or only in the second color?