--- a/devtools/client/inspector/grids/grid-inspector.js
+++ b/devtools/client/inspector/grids/grid-inspector.js
@@ -19,17 +19,17 @@ const {
   updateShowInfiniteLines,
 } = require("./actions/highlighter-settings");
 
 const SHOW_GRID_LINE_NUMBERS = "devtools.gridinspector.showGridLineNumbers";
 const SHOW_INFINITE_LINES_PREF = "devtools.gridinspector.showInfiniteLines";
 
 // Default grid colors.
 const GRID_COLORS = [
-  "#05E4EE",
+  "#4B0082",
   "#BB9DFF",
   "#FFB53B",
   "#71F362",
   "#FF90FF",
   "#FF90FF",
   "#1B80FF",
   "#FF2647"
 ];