Added support for background-size: contain

css/tests.css

@@ -177,3 +177,9 @@ h2 {
 /* Make sure that the rule is written out only once in case there is no rem substitution */
   background-size: cover;
 }
+#test-background-size-contain {
+  background-image: linear-gradient(90deg, transparent 50%, rgba(255,255,255,0.5) 50%);
+  background-size: contain  1px 1px;
+/* Make sure that the rule is written out only once in case there is no rem substitution */
+  background-size: contain;
+}

index.styl

@@ -21,7 +21,7 @@
 /* Convert unit to rems if unit is in pixels. */
 
 remify(value)
-	if value == 'inherit' || value == 'auto' || value == 'none' || value == 'cover' || value == 'smaller' || value == 0 || value == null
+	if value == 'inherit' || value == 'auto' || value == 'none' || value == 'cover' || value == 'contain' || value == 'smaller' || value == 0 || value == null
 		value
 	else if value == 'hairline'
 		'1px'

tests.html

@@ -91,6 +91,7 @@
 		<h2>Background size</h2>
 		<div id='test-background-size' data-assert='background-size: 500px 500px'>background-size 500px 500px</div>
 		<div id='test-background-size-cover' data-assert='background-size: cover'>background-size cover</div>
+		<div id='test-background-size-contain' data-assert='background-size: contain'>background-size contain</div>
 	</section>
 	<script src='dom-style-test-runner.js'></script>
 

tests.styl

@@ -132,4 +132,8 @@ h2
 
 #test-background-size-cover
 	background-image linear-gradient(90deg, transparent 50%, rgba(255,255,255,.5) 50%)
-	background-size cover
\ No newline at end of file
+	background-size cover
+
+#test-background-size-contain
+	background-image linear-gradient(90deg, transparent 50%, rgba(255,255,255,.5) 50%)
+	background-size contain
\ No newline at end of file