[css-color-5] fits svg figures into landscape viewports

Author: Adam Argyle

css-color-5/Overview.bs

@@ -94,7 +94,7 @@ it applies to all color channels.
 	Here is a top-down view, looking along the neutral L axis:
 
 	<figure>
-		<img src="images/CH-mixing.svg" style="width: 50vw">
+		<img src="images/CH-mixing.svg" style="width: 50vmin">
 		<figcaption>Mixtures of peru and lightgoldenrod.
 			Peru has a hue angle, measured from the positive a axis,
 			of 63.677 degrees
@@ -127,7 +127,7 @@ it applies to all color channels.
 	<pre class="lang-css">mix-color(red yellow 65%);</pre>
 
 	<figure>
-		<img src="images/CH-mixing3.svg" style="width: 50vw">
+		<img src="images/CH-mixing3.svg" style="width: 50vmin">
 		<figcaption>Mixtures of red and yellow.
 			Red has a hue angle, measured from the positive a axis,
 			of 40.8526 degrees
@@ -187,7 +187,7 @@ are copied across from the first color.
 	<pre class="lang-css">mix-color(lch(52% 58.1 22.7) lch(56% 49.1 257.1) hue(75.23%));</pre>
 
 	<figure>
-		<img src="images/CH-mixing2.svg" style="width: 50vw">
+		<img src="images/CH-mixing2.svg" style="width: 50vmin">
 		<figcaption>Mixtures of a red and a sky blue.
 			The red has a hue angle, measured from the positive a axis,
 			of 22.7 degrees