Improve warning message
diff --git a/R/landscape.R b/R/landscape.R
index 01ef2bb..d7b3cd1 100644
--- a/R/landscape.R
+++ b/R/landscape.R
@@ -13,7 +13,9 @@
 landscape <- function(kable_input, margin = NULL) {
   kable_format <- attr(kable_input, "format")
   if (!kable_format %in% c("html", "latex")) {
-    message("Currently generic markdown table using pandoc is not supported.")
+    warning("Please specify format in kable. kableExtra can customize either ",
+            "HTML or LaTeX outputs. See https://haozhu233.github.io/kableExtra/ ",
+            "for details.")
     return(kable_input)
   }
   if (kable_format == "html") {