diff --git a/doc/manual-src/en/_static/default2.css b/doc/manual-src/en/_static/default2.css
index 6afb67e93..2b24f118b 100644
--- a/doc/manual-src/en/_static/default2.css
+++ b/doc/manual-src/en/_static/default2.css
@@ -1,5 +1,5 @@
 @import url(http://fonts.googleapis.com/css?family=Roboto:400,400italic,500,500italic);
 
 pre, tt {
-    font-family: "Courier New", courier, monospace;
+    font-family:  monospace, sans-serif;
 }
diff --git a/doc/manual-src/ru/_static/default2.css b/doc/manual-src/ru/_static/default2.css
index 6afb67e93..2b24f118b 100644
--- a/doc/manual-src/ru/_static/default2.css
+++ b/doc/manual-src/ru/_static/default2.css
@@ -1,5 +1,5 @@
 @import url(http://fonts.googleapis.com/css?family=Roboto:400,400italic,500,500italic);
 
 pre, tt {
-    font-family: "Courier New", courier, monospace;
+    font-family:  monospace, sans-serif;
 }