Here’s what I did to try and hide custom fields in the registration form:
Use the inspector (right-click -> inspect element, in Chrome and Firefox) and then highlight the part of the form that you want to hide, like this:
Then right click on the selected
section and select copy -> CSS selector
In this example we have
I then added this to my custom CSS like this:
The only problem is: it doesn’t work. Or rather: it works at first but but the CSS selector seems to change every now and then so that this is not a permanent solution. I’m not sure when the ID changes, but presumably every time you rebuild the container or update Discourse.
As far as I understand the following post, the only way to make this permanent is by using a different way of identifying your element (n-th child), but I have not dug any further into this.