use the dark-gray variable

Author: jwcooper

assets/sass/layout/_header_mobile.scss

@@ -1,7 +1,7 @@
 @use "../base/variables";
 
 #mobile-header {
-  background-color: #333;
+  background-color: variables.$dark-gray;
 
   .header-contents {
     padding: 9px 5px 5px 8px;

assets/sass/pages/_espinstaller.scss

@@ -1,3 +1,5 @@
+@use "../base/variables";
+
 .cp-installer-dialog {
     min-width: 300px;
     min-height: 100px;
@@ -30,7 +32,7 @@
             content: ' ';
             height: 25px;
             width: 2px;
-            background-color: #333;
+            background-color: variables.$dark-gray;
         }
         &:before {
             transform: rotate(45deg);