diff --git a/Makefile b/Makefile
index e166c4e..6289c55 100644
--- a/Makefile
+++ b/Makefile
@@ -1,4 +1,23 @@
-TIDY ?= tidy-html5
+# make         Generate index.html from index.bs
+# make lint    Check index.bs for warnings and errors
+# make watch   Regenerate index.html after any change to index.bs
 
-tidy: index.html build/tidyconfig.txt
-	$(TIDY) -ashtml -config build/tidyconfig.txt -o $< $<
+LOCAL_BIKESHED := $(shell command -v bikeshed 2> /dev/null)
+
+index.html: index.bs
+ifndef LOCAL_BIKESHED
+	curl https://api.csswg.org/bikeshed/ -f -F file=@$< >$@;
+else
+	bikeshed spec
+endif
+
+ifdef LOCAL_BIKESHED
+.PHONY: lint watch
+
+lint: index.bs
+	bikeshed --print=plain --dry-run --die-when=late --line-numbers spec $<
+
+watch: index.bs
+	@echo 'Browse to file://${PWD}/index.html'
+	bikeshed --print=plain watch $<
+endif  # LOCAL_BIKESHED