Divi Toolbox ➜ Mobile ➜ Useful CSS Classes
The Divi Toolbox adds CSS snippets which will allow you to modify some elements on mobile. The custom CSS classes can be added to any element (section, row, column, or module) – and if the class is specific to an element, it will be noted in the class description.
Add this class to the Row Settings to switch the order of columns on mobile.
Add this class to the Text Module settings to center-align the text on mobile in that module.
Add this class to any Module to center-align it on mobile.
Add this class to the parent container – Row or Section – to center any Button Module within that parent on mobile.