#17129
@michael

In the child theme there should be a custom.css folder.

Go to: /buddyboss-child-fixed-navbar/css/custom.css.

Are you editing it in the WordPress admin? If so you should install WP Editor: http://wordpress.org/plugins/wp-editor/

WordPress editor by default won't let you see files in folder within the theme. That plugin will, along with many other benefits.