Use this code...
.rg-gm-slice, .rg-gm-slice a {
max-width: 100% ;
}
ul.rg-gm-slice-list li {
float: none !important;
}
This is how to create a custom CSS compatible with Gantry 4...
Simply create a file called "<TEMPLATENAME>-custom.css" and put this file in the CSS folder of the template (where <TEMPLATENAME> is the name of the template as seen in template manager e.g. rt_iridescent would be rt_iridescent-custom.css). GANTRY4 will automatically load this CSS file. If you wish, you can also have browser specific files by appending, for example, "-ie9" making the filename "<TEMPLATENAME>-custom-ie9.css"
Regards, Mark.