Here is what my style.css looks like after adding the code. But it did not change anything.
Joe
/*
THEME NAME:Headway Base
THEME URI:https://www.headwaythemes.com
VERSION:3.4.11
AUTHOR:Headway Themes
AUTHOR URI:https://www.headwaythemes.com
DESCRIPTION:Headway is a feature-packed theme with drag and drop layout editing, point and click design capabilities, powerful search engine optimization and much more. For help, you can access our support or go to the Headway codex.
LICENSE: Terms of Service
LICENSE URI: https://headwaythemes.com/terms-of-service
————————————————————————
Copyright 2009-2012 Vesped Inc.
This program 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 2 of the License, or
(at your option) any later version.
This program 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 this program; if not, write to the Free Software
Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
.metaslider .caption,
.metaslider .cs-title,
.metaslider .nivo-caption {
text-align: center;
}