diff --git a/lib/utils/style-gather.html b/lib/utils/style-gather.html
index 7a2bb37c50..56a5a5493c 100644
--- a/lib/utils/style-gather.html
+++ b/lib/utils/style-gather.html
@@ -46,7 +46,7 @@
      * @this {StyleGather}
      */
     cssFromModules(moduleIds) {
-      let modules = moduleIds.trim().split(' ');
+      let modules = moduleIds.trim().split(/\s+/);
       let cssText = '';
       for (let i=0; i < modules.length; i++) {
         cssText += this.cssFromModule(modules[i]);
diff --git a/test/unit/custom-style-import.html b/test/unit/custom-style-import.html
index f631c60d42..eb8503cce7 100644
--- a/test/unit/custom-style-import.html
+++ b/test/unit/custom-style-import.html
@@ -30,7 +30,8 @@
 <link rel="import" href="sub/style-import.html">
 
 <custom-style>
-<style is="custom-style" include="shared-style style-import">
+<style is="custom-style" include="shared-style style-import
+  style-import2">
   html {
 
     --import-mixin: {
diff --git a/test/unit/custom-style.html b/test/unit/custom-style.html
index 0ea22bfdd2..684ba102a3 100644
--- a/test/unit/custom-style.html
+++ b/test/unit/custom-style.html
@@ -393,6 +393,11 @@
         assert.include(url, 'sub/google.png');
       });
 
+      test('style paths can have arbitrary whitespace', function() {
+        var foo = document.querySelector('.foo');
+        assertComputed(foo, '4px', 'width');
+      });
+
       test('imperative custom style', function() {
         var cs = document.createElement('custom-style');
         var style = document.createElement('style');
diff --git a/test/unit/sub/style-import.html b/test/unit/sub/style-import.html
index b46759d37e..eaf7abb4cd 100644
--- a/test/unit/sub/style-import.html
+++ b/test/unit/sub/style-import.html
@@ -8,4 +8,14 @@
       }
     </style>
   </template>
+</dom-module>
+
+<dom-module id="style-import2">
+  <template>
+    <style>
+      .foo {
+        width: 4px;
+      }
+    </style>
+  </template>
 </dom-module>
\ No newline at end of file