diff --git a/R/colors.R b/R/colors.R
index 4db11d03..31b7c082 100644
--- a/R/colors.R
+++ b/R/colors.R
@@ -30,6 +30,9 @@
 #' @md
 #' @export
 parseCssColors <- function(str, mustWork = TRUE) {
+  # Logic below assumes
+  str[is.na(str)] <- ""
+
   # Strip insignificant whitespace
   str <- color_strip_ws(str)