I have recently started using the scss files, especially to customize Bootstrap.
To compile my scss files (and also bootstrap) i use sa
can't you keep the bootstrap and your custom css different . as traditionally we try to overwrite bootstrap with our custom css by using another external style , similarly if you want to learn sass try to create your new external stylesheet with sass , leaving the bootstrap code untouch and add your custom style below bootstrap import by only including main.scss which include your custom styles