diff --git a/core/modules/block/block.admin.css b/core/modules/block/block.admin.css
deleted file mode 100644
index 831ad44..0000000
--- a/core/modules/block/block.admin.css
+++ /dev/null
@@ -1,33 +0,0 @@
-#blocks tr.region-title td {
-  font-weight: bold;
-}
-#blocks tr.region-message {
-  font-weight: normal;
-  color: #999;
-}
-#blocks tr.region-populated {
-  display: none;
-}
-.block-region {
-  background-color: #ff6;
-  margin-top: 4px;
-  margin-bottom: 4px;
-  padding: 3px;
-}
-a.block-demo-backlink,
-a.block-demo-backlink:link,
-a.block-demo-backlink:visited {
-  background-color: #b4d7f0;
-  border-radius: 0 0 10px 10px;
-  color: #000;
-  font-family: "Lucida Grande", Verdana, sans-serif;
-  font-size: small;
-  line-height: 20px;
-  left: 20px; /*LTR*/
-  padding: 5px 10px;
-  position: fixed;
-  z-index: 499;
-}
-a.block-demo-backlink:hover {
-  text-decoration: underline;
-}
diff --git a/core/modules/block/css/block.admin.skin.css b/core/modules/block/css/block.admin.skin.css
new file mode 100644
index 0000000..831ad44
--- /dev/null
+++ b/core/modules/block/css/block.admin.skin.css
@@ -0,0 +1,33 @@
+#blocks tr.region-title td {
+  font-weight: bold;
+}
+#blocks tr.region-message {
+  font-weight: normal;
+  color: #999;
+}
+#blocks tr.region-populated {
+  display: none;
+}
+.block-region {
+  background-color: #ff6;
+  margin-top: 4px;
+  margin-bottom: 4px;
+  padding: 3px;
+}
+a.block-demo-backlink,
+a.block-demo-backlink:link,
+a.block-demo-backlink:visited {
+  background-color: #b4d7f0;
+  border-radius: 0 0 10px 10px;
+  color: #000;
+  font-family: "Lucida Grande", Verdana, sans-serif;
+  font-size: small;
+  line-height: 20px;
+  left: 20px; /*LTR*/
+  padding: 5px 10px;
+  position: fixed;
+  z-index: 499;
+}
+a.block-demo-backlink:hover {
+  text-decoration: underline;
+}