diff --git a/.marp/Makefile b/.marp/Makefile
index ac5522e..c87d09c 100644
--- a/.marp/Makefile
+++ b/.marp/Makefile
@@ -1,11 +1,12 @@
 
 all: build
 
-
 build: theme.css
 
 %.css: %.scss
-	cd .. && npx node-sass --output-style compressed .marp/$< > .marp/$@
+	cd .. \
+		&& npx node-sass --output-style compressed .marp/$< > .marp/$@ \
+		|| ( rm -f .marp/$@ && exit 1 )
 
 .PHONY: build