Add workaround for Semantic-Org/Semantic-UI#3070

indico/modules/rb_new/client/styles/main.scss

@@ -16,6 +16,7 @@
  */
 
 @import 'base/palette';
+@import 'rb_new:styles/sui_fixes';
 @import 'rb_new:styles/palette';
 @import 'rb_new:styles/forms';
 

indico/modules/rb_new/client/styles/sui_fixes.scss

@@ -0,0 +1,23 @@
+/* This file is part of Indico.
+ * Copyright (C) 2002 - 2019 European Organization for Nuclear Research (CERN).
+ *
+ * Indico is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation; either version 3 of the
+ * License, or (at your option) any later version.
+ *
+ * Indico is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with Indico; if not, see <http://www.gnu.org/licenses/>.
+ */
+
+@import 'base/palette';
+
+/* https://github.com/Semantic-Org/Semantic-UI/issues/3070 */
+.ui.inverted > .ui.modal > .close {
+    color: $dark-black;
+}