diff --git a/doc/_static/custom.css b/doc/_static/custom.css
new file mode 100644
index 0000000..f474a3e
--- /dev/null
+++ b/doc/_static/custom.css
@@ -0,0 +1,3 @@
+.pre {
+   font-family:SFMono-Regular,Menlo,Monaco,Consolas,Liberation Mono,Courier New,Courier,monospace;
+}