This documentation is more suited for developers as it involves tweaking CSS and/or PHP code.
Using CSS Tweaks
The membership login widget has a lot of CSS classes applied to it. You can use your own custom CSS tweaks to customize the look and feel of the various elements of the login widget.
Tweaking the PHP Template File
If you want to tweak the PHP template file for the login widget then do the following:
Step 1) Create a copy of the following files:
Step 2) Create a directory called “simple-membership” inside your theme (or child theme) folder.
Step 3) Upload these files (from step 1) inside your theme’s “simple-membership” folder.
So the custom template files will be in the following directory:
Step 4) Now you can customize the template files that you uploaded inside your theme folder (without having to modify the files in the core plugin).
The simple membership plugin will automatically load the template file (for the login widget) from your theme folder if it finds it there.