diff --git a/doc/css/style.sass b/doc/css/style.sass
index 5d2b15ec..69fc573a 100644
--- a/doc/css/style.sass
+++ b/doc/css/style.sass
@@ -6,7 +6,7 @@
 $separator: #CCCCCC
 
 $size_body_width: 60em
-$size_toc_width: 150px
+$size_toc_width: 250px
 
 $color_a: #569633
 $color_bg: #F9F9F9
diff --git a/doc/htdocs/css/style.css b/doc/htdocs/css/style.css
index 05b86603..e90ffb2c 100644
--- a/doc/htdocs/css/style.css
+++ b/doc/htdocs/css/style.css
@@ -116,7 +116,7 @@ div.container {
 #contents.sidebar {
   float: right;
   border-left: 1px solid #bbbbbb;
-  width: 150px;
+  width: 250px;
 }
 /* line 63, ../../css/style.sass */
 #contents.sidebar ul {
@@ -130,7 +130,7 @@ p.topic-title {
 
 /* line 69, ../../css/style.sass */
 div.section {
-  margin-right: 170px;
+  margin-right: 270px;
 }
 
 /* line 72, ../../css/style.sass */