Fix crates.io footer colours (#38)

Author: Frederick888

css/crates.io.css

@@ -439,3 +439,12 @@ img.download {
 [class^="_crate-downloads_"] [class^="_graph_"] text {
     fill: #c5c5c5;
 }
+
+/* footer */
+footer[class^="_footer_"] {
+    background: #0f1419;
+}
+
+footer[class^="_footer_"] [class^="_sep_"] {
+    color: #5c6773;
+}