--- a/devtools/client/themes/rules.css
+++ b/devtools/client/themes/rules.css
@@ -467,17 +467,17 @@
   margin-inline-end: 5px;
   display: inline-block;
   position: relative;
 }
 
 .ruleview-flex {
   background: url("chrome://devtools/skin/images/command-frames.svg");
   -moz-context-properties: fill;
-  fill: var(--rule-shape-toggle-color);
+  fill: var(--rule-flex-toggle-color);
   border-radius: 0;
   background-size: 1em;
 }
 
 .ruleview-grid {
   background: url("chrome://devtools/skin/images/grid.svg");
   border-radius: 0;
 }