[css-color-5] add LCH colorpicker example

Author: svgeesus

css-color-5/Overview.bs

@@ -41,8 +41,19 @@ Introduction {#intro}
 	this becomes even more useful to not need to manually set color,
 	and to instead have a single source from which schemes are calculated.
 
+	<figure>
+		<p><img src="images/LC-picker-scale.png" alt="LC color picker" style="width: 40vmin"><br/>
+			<img src="images/LC-picker-map2.png" alt="chloropleth map of the US" style="width: 48vmin"></p>
+		<figcaption>Above, a color picker operating in LCH space.
+			Here, a pair of colors are being used
+			to define a color scale
+			on the Chroma-Lightness plane (constant Hue).
+			Below, the color scale in use on a chloropleth map.
+		</figcaption>
+	</figure>
+
 	Currently Sass, calc() on HSL values, or PostCSS is used to do this.
-	Preprocessors are unable to work on dynamically adjusted colors,
+	However, preprocessors are unable to work on dynamically adjusted colors;
 	all current solutions are restricted to the sRGB gamut
 	and to the perceptual limitations of HSL
 	(colors are bunched up in the color wheel,
@@ -61,6 +72,8 @@ Introduction {#intro}
 	However, other colorspaces can be specified,
 	including ``hsl()`` or ``srgb`` if desired.
 
+
+
 Mixing colors: the ''color-mix'' function {#colormix}
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