diff --git a/src/main/java/org/owasp/html/CssSchema.java b/src/main/java/org/owasp/html/CssSchema.java
index 38e61326..c9e8a2ad 100644
--- a/src/main/java/org/owasp/html/CssSchema.java
+++ b/src/main/java/org/owasp/html/CssSchema.java
@@ -293,7 +293,7 @@ Property forKey(String propertyName) {
     ImmutableSet<String> mozOutlineLiterals3 = ImmutableSet.of(
         "hidden", "inherit", "inset", "invert", "medium", "none");
     ImmutableMap<String, String> mozOutlineFunctions =
-      ImmutableMap.<String, String>of("rgb(", "rgb()", "rgba(", "rgba()");
+      ImmutableMap.<String, String>of("rgb(", "rgb()", "rgba(", "rgba()","hsl(","hsl()","hsla(","hsla()");
     ImmutableSet<String> mozOutlineColorLiterals0 =
       ImmutableSet.of("inherit", "invert");
     ImmutableSet<String> mozOutlineStyleLiterals0 =
@@ -323,7 +323,7 @@ Property forKey(String propertyName) {
       .put("radial-gradient(", "radial-gradient()")
       .put("repeating-linear-gradient(", "repeating-linear-gradient()")
       .put("repeating-radial-gradient(", "repeating-radial-gradient()")
-      .put("rgb(", "rgb()").put("rgba(", "rgba()")
+      .put("rgb(", "rgb()").put("rgba(", "rgba()").put("hsl(", "hsl()").put("hsla(","hsla()")
       .build();
     ImmutableSet<String> backgroundAttachmentLiterals0 =
       ImmutableSet.of(",", "fixed", "local", "scroll");
@@ -467,6 +467,8 @@ Property forKey(String propertyName) {
     ImmutableSet<String> wordWrapLiterals0 = ImmutableSet.of(
         "break-word", "normal");
     ImmutableSet<String> rgb$FunLiterals0 = ImmutableSet.of(",");
+   
+    
     ImmutableSet<String> linearGradient$FunLiterals0 = ImmutableSet.of(
         ",", "to");
     ImmutableSet<String> radialGradient$FunLiterals0 = ImmutableSet.of(
@@ -742,6 +744,9 @@ Property forKey(String propertyName) {
     builder.put("zoom", new Property(1, fontStretchLiterals1, zeroFns));
     Property rgb$Fun = new Property(1, rgb$FunLiterals0, zeroFns);
     builder.put("rgb()", rgb$Fun);
+   
+    builder.put("hsl()", rgb$Fun);
+    builder.put("hsla()", rgb$Fun);
     @SuppressWarnings("unchecked")
     Property image$Fun = new Property(
         18, union(mozOutlineLiterals0, rgb$FunLiterals0), mozOutlineFunctions);
@@ -961,6 +966,8 @@ private static <T> ImmutableSet<T> union(
       "repeating-radial-gradient()",
       "rgb()",
       "rgba()",
+      "hsl()",
+      "hsla()",
       "richness",
       "speak",
       "speak-header",