Updated .not-editor styling based on @TomMalbran's feedback.

Author: Larz

src/styles/brackets.less

@@ -323,17 +323,6 @@ a, img {
     position: relative;
 
     /* Placeholder shown when there is no editor open */
-    .not-editor {
-        height: 100%;
-        .vbox;
-        .box-pack(center);
-        .box-align(center);
-        background: @bc-menu-bg url('images/no_content_bg.svg') no-repeat center 45%;
-
-        .dark & {
-            background: @dark-bc-menu-bg url('images/no_content_bg_dark.svg') no-repeat center 45%;
-        }
-    }
 
     .view-pane {
         opacity: 0.7; // quieten inactive pane
@@ -515,6 +504,19 @@ a, img {
     }
 }
 
+// moved this out of #editor-holder because we need to lower the specificity so theme authors can override the background color
+.not-editor {
+    height: 100%;
+    .vbox;
+    .box-pack(center);
+    .box-align(center);
+    background: #f8f8f8 url('images/no_content_bg.svg') no-repeat center 45%;
+
+    .dark & {
+        background: #1d1f21 url('images/no_content_bg_dark.svg') no-repeat center 45%;
+    }
+}
+
 // Split View Separator Styles
 .split-vertical #second-pane {
     border-left: 1px solid rgba(0, 0, 0, 0.17);