Upon investigating https://gitlab.com/gitlab-org/gitlab-ce/issues/59189, we noticed that the `input-group-text` which contains the hostname in front of the namespace selector, has larger text than the rest of the UI. This is due to a `font-size: 1rem` rule that's ultimately rendering the text at `16px`, instead of the standard `14px`.  Given `input-group-text` is used in multiple places, we need to figure out how to correct this without disrupting other usages of this.