diff --git a/doc/chm.but b/doc/chm.but
index fa6b6cde..3e9a577e 100644
--- a/doc/chm.but
+++ b/doc/chm.but
@@ -16,4 +16,8 @@
 \cfg{html-mshtmlhelp-contents}{putty.hhc}
 \cfg{html-mshtmlhelp-index}{putty.hhk}
 
+\cfg{html-body-end}{}
+
+\cfg{html-head-end}{<link rel="stylesheet" type="text/css" href="chm.css">}
+
 \versionid $Id$
diff --git a/doc/chm.css b/doc/chm.css
new file mode 100644
index 00000000..d8c316bf
--- /dev/null
+++ b/doc/chm.css
@@ -0,0 +1,7 @@
+/* Stylesheet for a Windows .CHM help file */
+
+body { font-size: 75%; font-family: Verdana, Arial, Helvetica, Sans-Serif; }
+
+h1 { font-weight: bold; font-size: 150%; }
+h2 { font-weight: bold; font-size: 130%; }
+h3 { font-weight: bold; font-size: 120%; }