CSS Disappearing When Editing Ghost Themes

Hello there, I am quite new to utilizing ghost and am trying to edit a theme for a newsletter-site that I am building. Unfortunately whenever I make any alteration (no matter how small) to the code, all of the CSS styling of the theme disappears and I am left with the ugly default html rendering with no styling at all. Even when I revert the changes that I made, the CSS styling remains gone. Does anyone know of any solutions to this issue?

This can happen to me when I forget to restart Ghost and/or clear all of my caches after making changes to any CSS, Templates, or other files.