diff --git a/addons/web/static/src/css/Makefile b/addons/web/static/src/css/Makefile
index f4f1f6d1bb5..ba88946baac 100644
--- a/addons/web/static/src/css/Makefile
+++ b/addons/web/static/src/css/Makefile
@@ -1,2 +1,5 @@
-sass:
-	sass -t expanded --compass --unix-newlines --watch base.sass:base.css&
\ No newline at end of file
+all: *.css
+%.css: %.sass
+	sass -t expanded --compass --unix-newlines $< $@
+watch:
+	sass -t expanded --compass --unix-newlines --watch .:.