Force user-supplied strings to UTF-8 encoding
diff --git a/R/row_spec.R b/R/row_spec.R
index ea96971..60d2a7c 100644
--- a/R/row_spec.R
+++ b/R/row_spec.R
@@ -175,7 +175,7 @@
                                    "deg);")
   }
   if (!is.null(extra_css)) {
-    xml_attr(x, "style") <- paste0(xml_attr(x, "style"), extra_css)
+    xml_attr(x, "style") <- paste0(xml_attr(x, "style"), enc2utf8(extra_css))
   }
   return(x)
 }