diff --git a/0023-on.keychord_press b/0023-on.keychord_press
index 6b6427b..0d80349 100644
--- a/0023-on.keychord_press
+++ b/0023-on.keychord_press
@@ -6,8 +6,10 @@ on.keychord_press = function(chord, key)
 		B()
 	elseif chord == 'C--' then
 		-- zoom out
-		Viewport.zoom = Viewport.zoom-0.1
-		B()
+		if (Viewport.zoom-0.1)*20 >= 1 then  -- disallow font size of 0
+			Viewport.zoom = Viewport.zoom-0.1
+			B()
+		end
 	elseif chord == 'C-0' then
 		-- reset zoom
 		Viewport.zoom = 1.0