BuddyPress.org

reset? what exactly do you mean? I trust you’re not going to tell us you edited the default styles directly are you? if you did, then rename your adjusted files to default-custom.css and copy a fresh set of default files in from a new download, then you can remove them afterwards and revert back to your custom files.

Later you will want to create a child theme so reverting can be done by changing themes in the backend.