Half of Django HTML suddenly gone white and not working


In ATOM 1.48 Out of the blue my half of my index.html file in a django project has all gone white and when I run it I only get the page title. All of my .py files seem to functioning normally, just the html, weirdly when I tab some of the lines or delete and rewrite portions of the code the colour returns but when I save and reopen it has disappeared.

I can’t figure out what to do…