[css-color-4] use consistent, correct values

for D50 reference white. Closes  #2492

Author: svgeesus

css-color-4/Overview.bs

@@ -3121,7 +3121,7 @@ function XYZ_to_Lab(XYZ) {
 	// from CIE standard, which now defines these as a rational fraction
 	var ε = 216/24389;  // 6^3/29^3
 	var κ = 24389/27;   // 29^3/3^3
-	var white = [0.9642, 1.0000, 0.8249]; // D50 reference white
+	var white = [[0.96422, 1.00000, 0.82521]; // D50 reference white
 
 	// compute xyz, which is XYZ scaled relative to reference white
 	var xyz = XYZ.map((value, i) => value / white[i]);
@@ -3140,7 +3140,7 @@ function Lab_to_XYZ(Lab) {
 	// Convert Lab to D50-adapted XYZ
 	var κ = 24389/27;   // 29^3/3^3
 	var ε = 216/24389;  // 6^3/29^3
-	var white = [0.9642, 1.0000, 0.8249]; // D50 reference white
+	var white = [[0.96422, 1.00000, 0.82521]; // D50 reference white
 	var f = [];
 
 	// compute f, starting with the luminance-related term