diff --git a/inst/rmarkdown/templates/revealjs_presentation/resources/default.html b/inst/rmarkdown/templates/revealjs_presentation/resources/default.html
index 85f300d..4f68da0 100644
--- a/inst/rmarkdown/templates/revealjs_presentation/resources/default.html
+++ b/inst/rmarkdown/templates/revealjs_presentation/resources/default.html
@@ -269,10 +269,14 @@
         // Implies `hash: true`
         history: $history$,
 $endif$
+$if(theme-ids)$
+        keyboard: { 8: 'prev' },
+$else$
 $if(keyboard)$
         // Enable keyboard shortcuts for navigation
         keyboard: $keyboard$,
 $endif$
+$endif$
 $if(disableLayout)$
   // Disables the default reveal.js slide layout (scaling and centering)
   // so that you can use custom CSS layout