Fix dark mode bug in button groups, remove button outlines in Chrome

static/css/base.css

@@ -246,3 +246,9 @@ pre {
 .nav-pills > li.active > a:focus {
     outline: 0;
 }
+
+/* no button outlines in Chrome--  */
+.btn-default.active,
+.btn-default.active.focus {
+    outline: 0;
+}

static/css/bootstrap-colors.css

@@ -9,6 +9,7 @@
 .btn-default:hover:active,
 .btn-default:focus,
 .btn-default:active,
+.btn-default.active.focus,
 .btn-default.active:hover {
     color: var(--btn-active-color);
     background-color: var(--btn-active-bg);