How to center the slider

.theme-bar.slider-wrapper {
    position: relative;
    border: 1px solid rgb(51, 51, 51);
    overflow: hidden;
    margin: 0 auto;
}

1. Use FTP: Locate the file bar.css
2. copy this file to the childtheme-folder of your site
3. Edit this file in your childtheme: locate the code for the above element and edit as above

You don’t have a childtheme yet?

1. Install and activate ‘one click childtheme plugin‘
2. create the childtheme
3. activate the newly created childtheme
4. Make the changes in the CHILDtheme!
   – copy php files / css-file(s) of the original theme [as required] to the childtheme directory and edit them as required.