diff --git a/style/themes/default-dark.css b/style/themes/default-dark.css
index c91ef7d8..d214f24e 100644
--- a/style/themes/default-dark.css
+++ b/style/themes/default-dark.css
@@ -512,4 +512,14 @@ fieldset[disabled] .form-control {
 .iradio_futurico,
 .iradio_minimal-blue {
 	margin-right: 8px;
+}
+
+/* Overlay box with spinners as shown during data collection for graphs */
+.box .overlay, .overlay-wrapper .overlay {
+	z-index: 50;
+  background: #353c42bb;
+	border-radius: 3px;
+}
+.box .overlay > .fa, .overlay-wrapper .overlay > .fa {
+  color: #bec5cb;
 }
\ No newline at end of file