[css-color-hdr] First cut at dynamic-range-limit-mix() w3c#9704

Author: svgeesus

css-color-hdr/Overview.bs

@@ -215,6 +215,22 @@ The 'dynamic-range-limit' property {#the-dynamic-range-limit-property}
 			</pre>
 		</div>
 
+Mixing Dynamic Range Limits: the ''dynamic-range-limit-mix()'' Function {#dynamic-range-limit-mix}
+--------------------------------------------------------
+
+	This function takes two dynamic-range-limit values,
+	converts them internally to a value in stops above media white,
+	and alters the display to the result of mixing them
+	by the specified amount.
+	The actual calculated result is not exposed.
+
+
+<pre class='prod'>
+	<dfn>dynamic-range-limit-mix()</dfn> = dynamic-range-limit-mix( [ <<ident>> && <<percentage [0,100]>>? ]#{2})
+</pre>
+
+	Percentages are normalized in the same way as ''color-mix()''.
+
 Predefined color spaces for HDR: {#predefined-HDR}
 =====================