Calendar dates incorrect on homepage

[danielfullmer]

Scrolling down on the main page at https://2020.nixcon.org/ shows the following:

Note that it shows the talks as starting on Thursday October 15, instead of Friday October 16.
If I click the "See the schedule here" link, I see the following:

Which I believe are the correct dates.

In case this is a timezone/locale issue, I'm currently in Pacific Time.

[addict3d]

Testing with timezone Etc/GMT, and changing the offset starting at -0 and moving right-to-left by an hour, so GMT-1, GMT-2, etc (and this timezone doesn't have daylight changing considerations).

The widget starts showing the wrong days at GMT-5.

GMT-4: Fri/Sat/Sun
GMT-5: Thu/Fri/Sat

The times shown were correct and localized to the offset (limited to the scope of testing written above).

If you view with GMT-12 (maybe you happen to hale from Baker Island and had time traveled so that you're currently observing standard time ) then the first talk finally is happening on Thursday, 11:00 PM, so I could see an argument being made for showing Thursday as the first day.

I haven't looked at the pretalx side yet, nor dug into the javascript in that widget. Clearly, some date time shenanigans are occurring.

[addict3d]

The homepage now mentions this info, from #34

My schedule is rather full at the moment. I'd like to dig in further and fix this before next week (being the start of the conference and all), but I put the odds of finding the time to do so around 10%.