diff --git a/devtools/shared/css/generated/properties-db.js b/devtools/shared/css/generated/properties-db.js
index 7e8e91162ab5..2e607a686ec0 100644
--- a/devtools/shared/css/generated/properties-db.js
+++ b/devtools/shared/css/generated/properties-db.js
@@ -357,6 +357,8 @@ exports.CSS_PROPERTIES = {
       "hidden",
       "hsl",
       "hsla",
+      "hwb",
+      "hwba",
       "inherit",
       "initial",
       "inset",
@@ -388,6 +390,8 @@ exports.CSS_PROPERTIES = {
       "currentColor",
       "hsl",
       "hsla",
+      "hwb",
+      "hwba",
       "inherit",
       "initial",
       "revert",
@@ -505,6 +509,8 @@ exports.CSS_PROPERTIES = {
       "hidden",
       "hsl",
       "hsla",
+      "hwb",
+      "hwba",
       "inherit",
       "initial",
       "inset",
@@ -536,6 +542,8 @@ exports.CSS_PROPERTIES = {
       "currentColor",
       "hsl",
       "hsla",
+      "hwb",
+      "hwba",
       "inherit",
       "initial",
       "revert",
@@ -1888,6 +1896,8 @@ exports.CSS_PROPERTIES = {
       "currentColor",
       "hsl",
       "hsla",
+      "hwb",
+      "hwba",
       "inherit",
       "initial",
       "inset",
@@ -2431,6 +2441,8 @@ exports.CSS_PROPERTIES = {
       "currentColor",
       "hsl",
       "hsla",
+      "hwb",
+      "hwba",
       "inherit",
       "initial",
       "revert",
@@ -2471,6 +2483,8 @@ exports.CSS_PROPERTIES = {
       "currentColor",
       "hsl",
       "hsla",
+      "hwb",
+      "hwba",
       "inherit",
       "initial",
       "medium",
@@ -2497,6 +2511,8 @@ exports.CSS_PROPERTIES = {
       "currentColor",
       "hsl",
       "hsla",
+      "hwb",
+      "hwba",
       "inherit",
       "initial",
       "revert",
@@ -2729,6 +2745,8 @@ exports.CSS_PROPERTIES = {
       "currentColor",
       "hsl",
       "hsla",
+      "hwb",
+      "hwba",
       "inherit",
       "initial",
       "revert",
@@ -3604,6 +3622,8 @@ exports.CSS_PROPERTIES = {
       "fixed",
       "hsl",
       "hsla",
+      "hwb",
+      "hwba",
       "image-set",
       "inherit",
       "initial",
@@ -3713,6 +3733,8 @@ exports.CSS_PROPERTIES = {
       "currentColor",
       "hsl",
       "hsla",
+      "hwb",
+      "hwba",
       "inherit",
       "initial",
       "revert",
@@ -3920,6 +3942,8 @@ exports.CSS_PROPERTIES = {
       "hidden",
       "hsl",
       "hsla",
+      "hwb",
+      "hwba",
       "inherit",
       "initial",
       "inset",
@@ -3961,6 +3985,8 @@ exports.CSS_PROPERTIES = {
       "hidden",
       "hsl",
       "hsla",
+      "hwb",
+      "hwba",
       "inherit",
       "initial",
       "inset",
@@ -3993,6 +4019,8 @@ exports.CSS_PROPERTIES = {
       "currentColor",
       "hsl",
       "hsla",
+      "hwb",
+      "hwba",
       "inherit",
       "initial",
       "revert",
@@ -4023,6 +4051,8 @@ exports.CSS_PROPERTIES = {
       "hidden",
       "hsl",
       "hsla",
+      "hwb",
+      "hwba",
       "inherit",
       "initial",
       "inset",
@@ -4054,6 +4084,8 @@ exports.CSS_PROPERTIES = {
       "currentColor",
       "hsl",
       "hsla",
+      "hwb",
+      "hwba",
       "inherit",
       "initial",
       "revert",
@@ -4125,6 +4157,8 @@ exports.CSS_PROPERTIES = {
       "hidden",
       "hsl",
       "hsla",
+      "hwb",
+      "hwba",
       "inherit",
       "initial",
       "inset",
@@ -4156,6 +4190,8 @@ exports.CSS_PROPERTIES = {
       "currentColor",
       "hsl",
       "hsla",
+      "hwb",
+      "hwba",
       "inherit",
       "initial",
       "revert",
@@ -4270,6 +4306,8 @@ exports.CSS_PROPERTIES = {
       "hidden",
       "hsl",
       "hsla",
+      "hwb",
+      "hwba",
       "inherit",
       "initial",
       "inset",
@@ -4301,6 +4339,8 @@ exports.CSS_PROPERTIES = {
       "currentColor",
       "hsl",
       "hsla",
+      "hwb",
+      "hwba",
       "inherit",
       "initial",
       "revert",
@@ -4412,6 +4452,8 @@ exports.CSS_PROPERTIES = {
       "currentColor",
       "hsl",
       "hsla",
+      "hwb",
+      "hwba",
       "inherit",
       "initial",
       "revert",
@@ -4617,6 +4659,8 @@ exports.CSS_PROPERTIES = {
       "hidden",
       "hsl",
       "hsla",
+      "hwb",
+      "hwba",
       "inherit",
       "initial",
       "inset",
@@ -4649,6 +4693,8 @@ exports.CSS_PROPERTIES = {
       "currentColor",
       "hsl",
       "hsla",
+      "hwb",
+      "hwba",
       "inherit",
       "initial",
       "revert",
@@ -4679,6 +4725,8 @@ exports.CSS_PROPERTIES = {
       "hidden",
       "hsl",
       "hsla",
+      "hwb",
+      "hwba",
       "inherit",
       "initial",
       "inset",
@@ -4710,6 +4758,8 @@ exports.CSS_PROPERTIES = {
       "currentColor",
       "hsl",
       "hsla",
+      "hwb",
+      "hwba",
       "inherit",
       "initial",
       "revert",
@@ -4781,6 +4831,8 @@ exports.CSS_PROPERTIES = {
       "hidden",
       "hsl",
       "hsla",
+      "hwb",
+      "hwba",
       "inherit",
       "initial",
       "inset",
@@ -4812,6 +4864,8 @@ exports.CSS_PROPERTIES = {
       "currentColor",
       "hsl",
       "hsla",
+      "hwb",
+      "hwba",
       "inherit",
       "initial",
       "revert",
@@ -4926,6 +4980,8 @@ exports.CSS_PROPERTIES = {
       "hidden",
       "hsl",
       "hsla",
+      "hwb",
+      "hwba",
       "inherit",
       "initial",
       "inset",
@@ -4957,6 +5013,8 @@ exports.CSS_PROPERTIES = {
       "currentColor",
       "hsl",
       "hsla",
+      "hwb",
+      "hwba",
       "inherit",
       "initial",
       "revert",
@@ -5045,6 +5103,8 @@ exports.CSS_PROPERTIES = {
       "hidden",
       "hsl",
       "hsla",
+      "hwb",
+      "hwba",
       "inherit",
       "initial",
       "inset",
@@ -5076,6 +5136,8 @@ exports.CSS_PROPERTIES = {
       "currentColor",
       "hsl",
       "hsla",
+      "hwb",
+      "hwba",
       "inherit",
       "initial",
       "revert",
@@ -5216,6 +5278,8 @@ exports.CSS_PROPERTIES = {
       "hidden",
       "hsl",
       "hsla",
+      "hwb",
+      "hwba",
       "inherit",
       "initial",
       "inset",
@@ -5247,6 +5311,8 @@ exports.CSS_PROPERTIES = {
       "currentColor",
       "hsl",
       "hsla",
+      "hwb",
+      "hwba",
       "inherit",
       "initial",
       "revert",
@@ -5390,6 +5456,8 @@ exports.CSS_PROPERTIES = {
       "currentColor",
       "hsl",
       "hsla",
+      "hwb",
+      "hwba",
       "inherit",
       "initial",
       "inset",
@@ -5510,6 +5578,8 @@ exports.CSS_PROPERTIES = {
       "currentColor",
       "hsl",
       "hsla",
+      "hwb",
+      "hwba",
       "inherit",
       "initial",
       "revert",
@@ -5613,6 +5683,8 @@ exports.CSS_PROPERTIES = {
       "currentColor",
       "hsl",
       "hsla",
+      "hwb",
+      "hwba",
       "inherit",
       "initial",
       "revert",
@@ -5757,6 +5829,8 @@ exports.CSS_PROPERTIES = {
       "hidden",
       "hsl",
       "hsla",
+      "hwb",
+      "hwba",
       "inherit",
       "initial",
       "inset",
@@ -5788,6 +5862,8 @@ exports.CSS_PROPERTIES = {
       "currentColor",
       "hsl",
       "hsla",
+      "hwb",
+      "hwba",
       "inherit",
       "initial",
       "revert",
@@ -6193,6 +6269,8 @@ exports.CSS_PROPERTIES = {
       "currentColor",
       "hsl",
       "hsla",
+      "hwb",
+      "hwba",
       "inherit",
       "initial",
       "none",
@@ -6422,6 +6500,8 @@ exports.CSS_PROPERTIES = {
       "currentColor",
       "hsl",
       "hsla",
+      "hwb",
+      "hwba",
       "inherit",
       "initial",
       "revert",
@@ -7672,6 +7752,8 @@ exports.CSS_PROPERTIES = {
       "currentColor",
       "hsl",
       "hsla",
+      "hwb",
+      "hwba",
       "inherit",
       "initial",
       "revert",
@@ -8860,6 +8942,8 @@ exports.CSS_PROPERTIES = {
       "hidden",
       "hsl",
       "hsla",
+      "hwb",
+      "hwba",
       "inherit",
       "initial",
       "inset",
@@ -8891,6 +8975,8 @@ exports.CSS_PROPERTIES = {
       "currentColor",
       "hsl",
       "hsla",
+      "hwb",
+      "hwba",
       "inherit",
       "initial",
       "revert",
@@ -10154,6 +10240,8 @@ exports.CSS_PROPERTIES = {
       "currentColor",
       "hsl",
       "hsla",
+      "hwb",
+      "hwba",
       "inherit",
       "initial",
       "revert",
@@ -10328,6 +10416,8 @@ exports.CSS_PROPERTIES = {
       "currentColor",
       "hsl",
       "hsla",
+      "hwb",
+      "hwba",
       "inherit",
       "initial",
       "revert",
@@ -10367,6 +10457,8 @@ exports.CSS_PROPERTIES = {
       "currentColor",
       "hsl",
       "hsla",
+      "hwb",
+      "hwba",
       "inherit",
       "initial",
       "none",
@@ -10620,6 +10712,8 @@ exports.CSS_PROPERTIES = {
       "from-font",
       "hsl",
       "hsla",
+      "hwb",
+      "hwba",
       "inherit",
       "initial",
       "line-through",
@@ -10649,6 +10743,8 @@ exports.CSS_PROPERTIES = {
       "currentColor",
       "hsl",
       "hsla",
+      "hwb",
+      "hwba",
       "inherit",
       "initial",
       "revert",
@@ -10749,6 +10845,8 @@ exports.CSS_PROPERTIES = {
       "filled",
       "hsl",
       "hsla",
+      "hwb",
+      "hwba",
       "inherit",
       "initial",
       "none",
@@ -10776,6 +10874,8 @@ exports.CSS_PROPERTIES = {
       "currentColor",
       "hsl",
       "hsla",
+      "hwb",
+      "hwba",
       "inherit",
       "initial",
       "revert",
@@ -10924,6 +11024,8 @@ exports.CSS_PROPERTIES = {
       "currentColor",
       "hsl",
       "hsla",
+      "hwb",
+      "hwba",
       "inherit",
       "initial",
       "none",
diff --git a/layout/inspector/tests/test_bug877690.html b/layout/inspector/tests/test_bug877690.html
index 309f961f0ba3..4ef93f39afde 100644
--- a/layout/inspector/tests/test_bug877690.html
+++ b/layout/inspector/tests/test_bug877690.html
@@ -32,7 +32,7 @@ function testValues(values, expected) {
 }
 
 function do_test() {
-  var allColors = [ "COLOR", "currentColor", "transparent", "rgb", "rgba", "hsl", "hsla" ];
+  var allColors = [ "COLOR", "currentColor", "transparent", "rgb", "rgba", "hsl", "hsla", "hwb", "hwba" ];
   var allGradients = [
     "linear-gradient",
     "-webkit-linear-gradient",
diff --git a/servo/components/style/values/specified/color.rs b/servo/components/style/values/specified/color.rs
index de9e42e4c32e..09c216d3026b 100644
--- a/servo/components/style/values/specified/color.rs
+++ b/servo/components/style/values/specified/color.rs
@@ -806,7 +806,7 @@ impl SpecifiedValueInfo for Color {
         // should probably be handled that way as well.
         // XXX `currentColor` should really be `currentcolor`. But let's
         // keep it consistent with the old system for now.
-        f(&["rgb", "rgba", "hsl", "hsla", "currentColor", "transparent"]);
+        f(&["rgb", "rgba", "hsl", "hsla", "hwb", "hwba", "currentColor", "transparent"]);
     }
 }