diff --git a/.gitignore b/.gitignore
index 7793b3adab..3417dba628 100644
--- a/.gitignore
+++ b/.gitignore
@@ -2,6 +2,7 @@
 /build/gh-pages
 /build/lint-spec-timestamp
 /build/lint-src-timestamp
+/build/ol.css
 /build/ol.js
 /build/ol-all.js
 /build/proj4js-combined.js
diff --git a/Makefile b/Makefile
index 316850987b..b986a0728f 100644
--- a/Makefile
+++ b/Makefile
@@ -15,9 +15,9 @@ all: build-all build examples
 precommit: lint build-all doc test build
 
 .PHONY: build
-build: build/ol.js
+build: build/ol.css build/ol.js
 
-build/ol.js: $(PLOVR_JAR) $(SRC) base.json build/ol.json
+build/ol.js build/ol.css: $(PLOVR_JAR) $(SRC) base.json build/ol.json
 	java -jar $(PLOVR_JAR) build build/ol.json >$@
 	@echo $@ "uncompressed:" $$(wc -c <$@) bytes
 	@echo $@ "  compressed:" $$(gzip -9 -c <$@ | wc -c) bytes
@@ -77,6 +77,7 @@ test:
 clean:
 	rm -f build/lint-spec-timestamp
 	rm -f build/lint-src-timestamp
+	rm -f build/ol.css
 	rm -f build/ol.js
 	rm -f build/ol-all.js
 	rm -f build/require-all.js
diff --git a/build/ol.json b/build/ol.json
index 8a0951c37d..65b952831c 100644
--- a/build/ol.json
+++ b/build/ol.json
@@ -2,6 +2,16 @@
 
   "id": "ol",
 
+  "css-allowed-unrecognized-properties": [
+    "user-select"
+  ],
+
+  "css-inputs": [
+    "css/ol.css"
+  ],
+
+  "css-output-file": "build/ol.css",
+
   "externs": [
     "externs/bingmaps.js",
     "externs/ol.js",
diff --git a/css/ol.css b/css/ol.css
index 9d4e6bbc06..3261f3a4ed 100644
--- a/css/ol.css
+++ b/css/ol.css
@@ -34,12 +34,12 @@
   height: 22px;
   width:22px;
   line-height: 19px;
-  background: #130085; /* fallback for IE - IE6 requires background shorthand*/
+  background: #130085; /* @alternate */ /* fallback for IE - IE6 requires background shorthand*/
   background: rgba(0, 60, 136, 0.5);
   filter: alpha(opacity=80);
 }
 .ol-zoom a:hover {
-  background: #130085; /* fallback for IE */
+  background: #130085; /* @alternate */ /* fallback for IE */
   background: rgba(0, 60, 136, 0.7);
   filter: alpha(opacity=100);
 }
@@ -188,12 +188,12 @@
     height: 22px;
     width:22px;
     line-height: 19px;
-    background: #130085; /* fallback for IE - IE6 requires background shorthand*/
+    background: #130085; /* @alternate */ /* fallback for IE - IE6 requires background shorthand*/
     background: rgba(0, 60, 136, 0.5);
     filter: alpha(opacity=80);
 }
 .ol-control-zoom a:hover {
-    background: #130085; /* fallback for IE */
+    background: #130085; /* @alternate */ /* fallback for IE */
     background: rgba(0, 60, 136, 0.7);
     filter: alpha(opacity=100);
 }
@@ -215,7 +215,7 @@
     color: #eeeeee;
     bottom: 0;
     right: 0;
-    background: #130085; /* fallback for IE - IE6 requires background shorthand*/
+    background: #130085; /* @alternate */ /* fallback for IE - IE6 requires background shorthand*/
     background: rgba(0, 60, 136, 0.3);
     filter: alpha(opacity=30);
     font-family: 'Lucida Grande', Verdana, Geneva, Lucida, Arial, Helvetica, sans-serif;