Changed root directory name lost css, images

Where are the settings for the directory structure set? I changed the directory name “grav-skeleton-onepage-site” to “onepage” and lost all the CSS, images and structure.

Just clear the cache:

bin/grav clear-cache

Thanks, Andy. That worked.

That is something that an end-user will not be able to do without SSH access. Will this be included in the admin panel?

Yup, it will be included in the admin panel.