White screen of death – haven't touched my WP install

My sister’s WordPress install resides here: xenialatii.com/portfolio

Earlier today, I was tinkering with a different, non-WP related section of my website, and when I checked the WordPress install, it gave me nothing but the white screen of death.

Only change I made that could have something to do with WordPress is editing the index.php file that I used to have in the root: it used to be a redirect to /portfolio and now it’s been replaced by an index.html which is actually a webpage.

So, essentially, I didn’t touch the WordPress install and I’d really appreciate any help I can get with this sudden white screen of death.

Things I already tried, to no avail:
– renaming my plugins folder
– renaming my WP theme so it automatically uses the original theme
– adding more memory to my wp-config.php

Thanks!