[css-color-adjust-1] Use 'surface' to distinguish canvas background from what lies underneath. #3949

Author: fantasai

css-color-adjust-1/Overview.bs

@@ -82,7 +82,7 @@ Preferred Color Schemes {#preferred}
 	(see 'color-scheme'),
 	the user agent must match the following to the user's preferred [=color scheme=]:
 
-	* the initial color of the [=canvas=]
+	* the color of the [=canvas=] surface
 	    <span class=issue>find what we name this in other specs</span>,
 		the initial value of the '/color' property,
 		and the [[css-color-4#css-system-colors|system colors]]
@@ -240,7 +240,8 @@ Effects of the Used Color Scheme {#color-scheme-effect}
 	to match with the intent of the [=color scheme=].
 
 	On the root element,
-	rendering with a [=color scheme=] additionally must affect the background of the [=canvas=],
+	rendering with a [=color scheme=] additionally must affect
+	the surface color of the [=canvas=],
 	the initial value of the '/color' property,
 	and the used values of the [[css-color-4#css-system-colors|system colors]],
 	and should also affect the viewport's scrollbars.