diff --git a/test/sample-book/src/style.css b/test/sample-book/src/style.css
index cc421c546..ee18b53bd 100644
--- a/test/sample-book/src/style.css
+++ b/test/sample-book/src/style.css
@@ -66,7 +66,7 @@ p {
     line-height: 1.6;
 }
 div.lead p {
-	color: #666;
+    color: #666;
     line-height: 1.6;
     font-size: 0.75em;
 }
diff --git a/test/syntax-book/style.css b/test/syntax-book/style.css
index cc421c546..ee18b53bd 100644
--- a/test/syntax-book/style.css
+++ b/test/syntax-book/style.css
@@ -66,7 +66,7 @@ p {
     line-height: 1.6;
 }
 div.lead p {
-	color: #666;
+    color: #666;
     line-height: 1.6;
     font-size: 0.75em;
 }