If I paste your code into the editor and run it, the tests pass successfully. This may be a bug — what happens if you reset your code, then copy and paste it into the editor again?
I can’t replicate the problem on my Windows 10 machine with the latest versions of Chrome or Firefox. I’d suggest upgrading to the latest Firefox version and seeing if that fixes the problem. Then, whether or not it fixed the problem, you can file a bug report here: https://github.com/freeCodeCamp/freeCodeCamp/issues
Out of interest, was the browser info in your original post correct (Firefox 52)? According to caniuse, anything IE9 or newer should be fine for HSL colors. That suggests a bug with the challenge itself if you were using an even moderately new browser version (unless it’s simply that one of fCC’s dependencies only works with the newest browsers).