diff --git a/assets/css/extended/custom_fonts.css b/assets/css/extended/custom_fonts.css
index da05dfd..58d9b47 100644
--- a/assets/css/extended/custom_fonts.css
+++ b/assets/css/extended/custom_fonts.css
@@ -28,28 +28,28 @@
 
 @font-face {
   font-family: "CM";
-  src: url("/fonts/NewCM10-Bold.otf") format("opentype");
+  src: url("/fonts/NewCM10-Bold.ttf") format("truetype");
   font-weight: bold;
   font-style: normal;
 }
 
 @font-face {
   font-family: "CM";
-  src: url("/fonts/NewCM10-Regular.otf") format("opentype");
+  src: url("/fonts/NewCM10-Book.ttf") format("truetype");
   font-weight: normal;
   font-style: normal;
 }
 
 @font-face {
   font-family: "CM";
-  src: url("/fonts/NewCM10-BoldItalic.otf") format("opentype");
+  src: url("/fonts/NewCM10-BoldItalic.ttf") format("truetype");
   font-weight: bold;
   font-style: italic;
 }
 
 @font-face {
   font-family: "CM";
-  src: url("/fonts/NewCM10-Italic.otf") format("opentype");
+  src: url("/fonts/NewCM10-BookItalic.ttf") format("truetype");
   font-weight: normal;
   font-style: italic;
 }