For the website I'm trying to build I have to create custom button styles (unless there's a way to customize the default button styles).

This is easy enough when you edit the custom CSS/SCSS through the editor provided by the platform. But when I update the button styles and go back to the content editor, the "Save" button has fallen off the screen.

I'm editing the following button class using SCSS:

.btn {
    &.btn-outline-secondary {
        // style
    }
}

When I check the classes of the "Save" button in the browsers HTML editor it uses:

.btn.btn-primary

Which shouldn't mingle at all.

Does anyone else have this problem?
How can I fix this?

Thank you in advance!