diff --git a/private/html.rkt b/private/html.rkt
index 32351d4..ce1bd36 100644
--- a/private/html.rkt
+++ b/private/html.rkt
@@ -129,12 +129,12 @@
                 '((br ()))))
 
 (define (mode-xml mode body)
-  (define color
+  (define class
     (case mode
-      [(yes) "green"]
-      [(no) "red"]
-      [(missing) "black"]))
-  `(span ((style ,(string-append "color:" color))) ,@body))
+      [(yes) "covered"]
+      [(no) "uncovered"]
+      [(missing) "missing"]))
+  `(span ((class ,class)) ,@body))
 
 (module+ test
   (define (test file out)
@@ -145,5 +145,5 @@
     (clear-coverage!))
   (define f (path->string (simplify-path path)))
   (test f
-        `((span ((style "color:green"))
+        `((span ((class "covered"))
           ,@(encode-string (file->string f))))))
diff --git a/private/main.css b/private/main.css
index 10f9bb5..a06a5f3 100644
--- a/private/main.css
+++ b/private/main.css
@@ -1,3 +1,13 @@
 .code {
     font-family: "Lucida Console", Monaco, monospace;
-}
\ No newline at end of file
+}
+
+.uncovered {
+    color:red;
+}
+
+.covered {
+    color:green;
+}
+
+.missing {}
\ No newline at end of file