diff --git a/devtools/client/inspector/inspector.css b/devtools/client/inspector/inspector.css
deleted file mode 100644
index efbfbc076f4b..000000000000
--- a/devtools/client/inspector/inspector.css
+++ /dev/null
@@ -1,30 +0,0 @@
-/* vim:set ts=2 sw=2 sts=2 et: */
-/* This Source Code Form is subject to the terms of the Mozilla Public
- * License, v. 2.0. If a copy of the MPL was not distributed with this
- * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
-
-/* Set the minimum width for the side bar so, all tabs are
-  properly visible. The value can be decreased when bug 1281789
-  is fixed and the all-tabs-menu is available again. */
-#inspector-sidebar-container {
-  overflow: hidden;
-  min-width: 450px;
-  position: relative;
-}
-
-#inspector-sidebar {
-  position: absolute;
-  top: 0;
-  bottom: 0;
-  left: 0;
-  right: 0;
-}
-
-/* Override `-moz-user-focus:ignore;` from toolkit/content/minimal-xul.css */
-.inspector-tabpanel > * {
-  -moz-user-focus: normal;
-}
-
-#inspector-sidebar-toggle-box {
-  line-height: initial;
-}
diff --git a/devtools/client/inspector/inspector.xul b/devtools/client/inspector/inspector.xul
index d185c9bb06e4..ce3710cf08b4 100644
--- a/devtools/client/inspector/inspector.xul
+++ b/devtools/client/inspector/inspector.xul
@@ -4,7 +4,6 @@
    - file, You can obtain one at http://mozilla.org/MPL/2.0/. -->
 <?xml-stylesheet href="chrome://global/skin/" type="text/css"?>
 <?xml-stylesheet href="chrome://devtools/content/shared/widgets/widgets.css" type="text/css"?>
-<?xml-stylesheet href="chrome://devtools/content/inspector/inspector.css" type="text/css"?>
 <?xml-stylesheet href="chrome://devtools/skin/widgets.css" type="text/css"?>
 <?xml-stylesheet href="chrome://devtools/skin/inspector.css" type="text/css"?>
 <?xml-stylesheet href="chrome://devtools/skin/rules.css" type="text/css"?>
diff --git a/devtools/client/jar.mn b/devtools/client/jar.mn
index d9a8f1284a6c..fb4cec891eb7 100644
--- a/devtools/client/jar.mn
+++ b/devtools/client/jar.mn
@@ -143,7 +143,6 @@ devtools.jar:
 *   content/framework/dev-edition-promo/dev-edition-promo.css (framework/dev-edition-promo/dev-edition-promo.css)
     content/framework/dev-edition-promo/dev-edition-logo.png (framework/dev-edition-promo/dev-edition-logo.png)
     content/inspector/inspector.xul (inspector/inspector.xul)
-    content/inspector/inspector.css (inspector/inspector.css)
     content/framework/connect/connect.xhtml (framework/connect/connect.xhtml)
     content/framework/connect/connect.css (framework/connect/connect.css)
     content/framework/connect/connect.js (framework/connect/connect.js)
diff --git a/devtools/client/themes/inspector.css b/devtools/client/themes/inspector.css
index b10612b61678..63d23f270623 100644
--- a/devtools/client/themes/inspector.css
+++ b/devtools/client/themes/inspector.css
@@ -25,6 +25,13 @@
   display: inline-block;
 }
 
+/* Add element toolbar button */
+#inspector-element-add-button::before {
+  background-image: url("chrome://devtools/skin/images/add.svg");
+  list-style-image: url("chrome://devtools/skin/images/add.svg");
+  -moz-user-focus: normal;
+}
+
 #inspector-searchlabel {
   overflow: hidden;
   margin-inline-end: 2px;
@@ -52,6 +59,21 @@
   line-height: 17px;
 }
 
+/* Eyedropper toolbar button */
+
+#inspector-eyedropper-toggle {
+  /* hidden by default, until we can check that the required highlighter exists */
+  display: none;
+}
+
+#inspector-eyedropper-toggle::before {
+  background-image: var(--eyedropper-image);
+}
+
+#inspector-sidebar-toggle-box {
+  line-height: initial;
+}
+
 #inspector-breadcrumbs-toolbar {
   padding: 0px;
   border-bottom-width: 0px;
@@ -97,21 +119,25 @@
   font: message-box;
 }
 
-/* Eyedropper toolbar button */
-
-#inspector-eyedropper-toggle {
-  /* hidden by default, until we can check that the required highlighter exists */
-  display: none;
+/* Set the minimum width for the side bar so, all tabs are
+  properly visible. The value can be decreased when bug 1281789
+  is fixed and the all-tabs-menu is available again. */
+#inspector-sidebar-container {
+  overflow: hidden;
+  min-width: 450px;
+  position: relative;
 }
 
-#inspector-eyedropper-toggle::before {
-  background-image: var(--eyedropper-image);
+#inspector-sidebar {
+  position: absolute;
+  top: 0;
+  bottom: 0;
+  left: 0;
+  right: 0;
 }
 
-/* Add element toolbar button */
-#inspector-element-add-button::before {
-  background-image: url("chrome://devtools/skin/images/add.svg");
-  list-style-image: url("chrome://devtools/skin/images/add.svg");
+/* Override `-moz-user-focus:ignore;` from toolkit/content/minimal-xul.css */
+.inspector-tabpanel > * {
   -moz-user-focus: normal;
 }