diff --git a/webroot/css/co-grouper-base.css b/webroot/css/co-grouper-base.css
index 8080b7f..3d77f57 100644
--- a/webroot/css/co-grouper-base.css
+++ b/webroot/css/co-grouper-base.css
@@ -24,5 +24,10 @@
     background-color: var(--danger);
     border-color: var(--danger);
     color: white;
+    filter: grayscale(20%);
     box-shadow: 0 2px 2px 0 rgba(0, 0, 0, .14), 0 3px 1px -2px rgba(0, 0, 0, .2), 0 1px 5px 0 rgba(0, 0, 0, .12);
+}
+
+.grouper .btn.btn-danger.btn-grouper:hover {
+    background-color: var(--danger);
 }
\ No newline at end of file