diff --git a/devtools/client/themes/layoutview.css b/devtools/client/themes/layoutview.css
index 642e89c6d42..125d7f24724 100644
--- a/devtools/client/themes/layoutview.css
+++ b/devtools/client/themes/layoutview.css
@@ -6,7 +6,7 @@
   box-sizing: border-box;
 }
 
-body {
+.theme-sidebar body {
   /* The view will grow bigger as the window gets resized, until 400px */
   max-width: 400px;
   margin: 0px auto;