An internal server error (500) upon trying to submit a particular userstyle

[YellowAfterlife]

Stylesheet and form data: https://gist.github.com/YellowAfterlife/b3bdf298a7b905b94232

Error 500 is not exactly a descriptive one so I'm having trouble narrowing down the issue.
At the same time I was able to submit other tiny userstyle for a test just fine.

[LouCypher]

There is slightlyLighter key in color-scheme option but there's no /*[[slightlyLighter]]*/ in your main CSS. The site should give the correct error message though.

Similar issue: https://forum.userstyles.org/discussion/42195/my-style-won-t-install-getting-status-500-message/p1

[alkaris2]

THis issue has returned. Server Error 500 when submitting, but returns; JSON.parse: unexpected character at line 1 column 1 of the JSON data when trying to submit.

[YellowAfterlife]

THis issue has returned. Server Error 500 when submitting, but returns; JSON.parse: unexpected character at line 1 column 1 of the JSON data when trying to submit.

That's probably something else - open your own issue and include your submission fields there