diff --git a/src/web/stylesheets/components/io/_io.css b/src/web/stylesheets/components/io/_io.css
index d901f054..dc941a9f 100755
--- a/src/web/stylesheets/components/io/_io.css
+++ b/src/web/stylesheets/components/io/_io.css
@@ -182,3 +182,8 @@ label[for="output-text"] {
     padding: 10px;
     text-align: center;
 }
+
+#input .cm-panels,
+#output .cm-panels {
+    border-color: var(--primary-border-colour);
+}