[css-color-5] fix w3c#4734

Author: svgeesus

css-color-5/Overview.bs

@@ -82,18 +82,18 @@ Mixing colors: the ''color-mix'' function {#colormix}
 <div class="example">
 	This example produces the mixture of a deep green and a sky blue,
 	in ''lch()'' colorspace (the default),
-	with the lightness being 50% of the lightness of the green
-	(and thus, 50% of the lightness of the blue).
+	with the lightness being 40% of the lightness of the green
+	(and thus, 60% of the lightness of the blue).
 	The chroma and hue of the green are left unchanged.
 
-	<pre class="lang-css">mix-color(rgb(0% 42.35% 33.33%), rgb(41.2% 69.88% 96.64%), lightness(50%));</pre>
+	<pre class="lang-css">mix-color(rgb(0% 42.35% 33.33%), rgb(41.2% 69.88% 96.64%), lightness(40%));</pre>
 
 	The calculation is as follows:
 	  * <span class="swatch" style="--color: rgb(0% 42.35% 33.33%)"></span> rgb(0% 42.35% 33.33%) is lch(40.083% 32.808 171.175)
 	  * <span class="swatch" style="--color: rgb(41.2% 69.88% 96.64%)"></span> rgb(41.2% 69.88% 96.64%) is lch(70% 42.5 258.2)
-	  * mix lightness is 40.083 * 0.5 + 70% * 0.5 = 55.0415
-	  * mixed result is <span class="swatch" style="--color: rgb(22.87% 57.56% 47.73%)"></span> lch(55.0415 32.808 171.175)
-	  * which is a <span class="swatch" style="--color:  rgb(22.87% 57.56% 47.73%)"></span>  rgb(22.87% 57.56% 47.73%), a lighter green
+	  * mix lightness is 40.083 * 0.4 + 70% * (1 - 0.4) = 58.0332
+	  * mixed result is <span class="swatch" style="--color: rgb(26.25% 60.68% 50.72%)"></span> lch(58.0332 32.808 171.175)
+	  * which is a <span class="swatch" style="--color:  rgb(26.25% 60.68% 50.72%)"></span>  rgb(26.25% 60.68% 50.72%), a lighter green
 
 </div>