diff --git a/package.json b/package.json
index 9025c91..1c390a3 100644
--- a/package.json
+++ b/package.json
@@ -17,7 +17,7 @@
     "index.js"
   ],
   "dependencies": {
-    "css-color-function": "^1.3.0",
+    "css-color-function": "~1.3.3",
     "postcss": "^6.0.1",
     "postcss-message-helpers": "^2.0.0",
     "postcss-value-parser": "^3.3.0"
diff --git a/test/fixtures/color.css b/test/fixtures/color.css
index 4ee21ac..335dc73 100644
--- a/test/fixtures/color.css
+++ b/test/fixtures/color.css
@@ -10,3 +10,9 @@ body {
 
   border-color: color(#999 a(0.8)) color(#999 a(0.8));
 }
+
+.withAlpha {
+  color: color(black a(80%) contrast(99%));
+  background-color: color(red a(50%) shade(50%));
+  border-color: color(red a(80%) tint(50%));
+}
diff --git a/test/fixtures/color.expected.css b/test/fixtures/color.expected.css
index 01cea60..f525b85 100644
--- a/test/fixtures/color.expected.css
+++ b/test/fixtures/color.expected.css
@@ -10,3 +10,9 @@ body {
 
   border-color: rgba(153, 153, 153, 0.8) rgba(153, 153, 153, 0.8);
 }
+
+.withAlpha {
+  color: rgba(255, 255, 255, 0.8);
+  background-color: rgba(128, 0, 0, 0.5);
+  border-color: rgba(255, 128, 128, 0.8);
+}