[css-color-4] Stop claiming that achromatic colors have missing chroma.

#8609

css-color-4/Overview.bs

@@ -2056,7 +2056,8 @@ HSL Colors: ''hsl()'' and ''hsla()'' functions</h2>
 	If the saturation of an HSL color is ''0%'',
 	then the hue component is [=powerless=].
 	If the lightness of an HSL color is ''0%'' or ''100%'',
-	both the saturation and hue components are [=powerless=].
+	the hue component is [=powerless=]
+	and the saturation is ''0%''.
 
 	<div class='example' id="ex-hsl-primary-red">
 		For example, an ordinary red,
@@ -3140,7 +3141,7 @@ Specifying Lab and LCH: the ''lab()'' and ''lch()'' functional notations</h3>
 
 	If the lightness of a Lab color (after clamping) is ''0%'',
 	or ''100%''
-	both the a and b components are [=powerless=]
+	both the a and b components are ''0''
 	and the color represents black, or white, respectively.
 
 	<div class="example" id="ex-lab-samples">
@@ -3218,7 +3219,8 @@ Specifying Lab and LCH: the ''lab()'' and ''lch()'' functional notations</h3>
 	the hue component is [=powerless=].
 	If the lightness of an LCH color (after clamping) is ''0%'',
 	or ''100%'', 
-	both the hue and chroma components are [=powerless=].
+	the hue component is [=powerless=]
+	and the chroma is ''0''.
 
 	<div class="example" id="ex-lch-samples">
 		<pre class="lang-css">
@@ -3302,7 +3304,7 @@ Specifying Lab and LCH: the ''lab()'' and ''lch()'' functional notations</h3>
 
 	If the lightness of an Oklab color is ''0%'' or 0,
 	or ''100%'' or 1.0,
-	both the a and b components are [=powerless=]
+	both the a and b components are 0
 	and the color represents black, or white, respectively.
 
 	<div class="example" id="ex-oklab-samples">
@@ -3379,7 +3381,8 @@ Specifying Lab and LCH: the ''lab()'' and ''lch()'' functional notations</h3>
 		the hue component is [=powerless=].
 		If the lightness of an Oklch color is ''0%'' or 0,
 		or ''100%'' or 1.0,
-		both the hue and chroma components are [=powerless=].
+		the hue component is [=powerless=]
+		and the chroma is ''0''.
 
 		<div class="example" id="ex-oklch-samples">
 			<pre class="lang-css">