Issues with updating Casper theme


I managed to run Ghost locally in order to modify the Casper theme.
However after any tiny change and saving the file (for example default.hbs), the CSS kind of breaks and page looks bad. What is funny if I undo the change and save the file it still breaks and doesn’t come back to previous state? Am I missing some asset/compile build step?

I remember this method of modifying code of the theme was working in Ghost 3.0.

I saw this as well when I played with Casper.

For me it was browser cache and chrome always redirecting to HTTPS I think.