Steps to reproduce:

1. Navigate to https://hammertime.cyou/.
   a. If you're not in a locale that's currently experiencing DST, you'll need to first select a locale that experiences DST and type in a date that is subject to DST (for example: America/New_York and July 1st). Most people won't need this step, but it's included for completeness.
2. Type in "2038" (or any subsequent year) for the year value.
3. Notice that the timestamp is calculated incorrectly, and the displayed time is one hour off from the time that is typed in

For comparison, here's are two timestamps that are correctly calculated:

Year prior to 2038:	Non-DST date:

Note that the problem here is in the calculation of the timestamp itself: the displayed times are correct, as far as I can tell, and match with how discord displays the calculated unix timestamps (e.g. <t:2158988400:f>), as well as how wolfram alpha displays them: https://www.wolframalpha.com/input?i=2158988400+seconds+after+unix+epoch