Merge pull request w3c#6560 from andruud/color_contrast_resolved

[css-color-5] Resolving color-contrast()

Author: svgeesus

css-color-5/Overview.bs

@@ -682,6 +682,38 @@ Selecting the most contrasting color: the ''color-contrast()'' function {#colorc
 		<!-- great example to use in WPT -->
 	</div>
 
+	<h3 id="resolving-contrast">Resolving ''color-contrast()'' values</h3>
+
+	The computed value is the specified ''color-contrast()'' function
+	with each <<color>> parameter resolved according to [[css-color-4#resolving-color-values]],
+	and the keywords ''AA'', ''AA-large'', ''AAA'', ''AAA-large'' replaced with their corresponding numeric value.
+
+	The used value is the winning color
+	resolved according to [[css-color-4#resolving-color-values]].
+
+	<div class="example">
+
+		For example, given a current color value of
+		<span class="swatch" style="--color: rgb(179 213 230)"></span> rgb(179 213 230),
+		the value
+
+		<pre class="lang-css">
+			color-contrast(currentColor vs hsl(200 83% 23%), purple to AA)
+		</pre>
+
+		has the computed value
+
+		<pre class="lang-css">
+			color-contrast(currentColor vs rgb(10 75 107), rgb(128 0 128) to 4.5)
+		</pre>
+
+		and the used value
+
+		<pre class="lang-css">
+			rgb(128 0 128)
+		</pre>
+
+	</div>
 
 
 <!-- old color-adjust wording might be useful, on choice of color space for adjustment -->
@@ -1318,4 +1350,5 @@ Changes {#changes}
 	<li>allowed mix percent to default to 50%</li>
 	<li>added worked examples and diagrams</li>
 	<li>corrected minor spelling, syntax and formatting issues</li>
+	<li>Added section on resolving color-contrast() values</li>
 </ul>