DST Reference

This is a reference note, not a date calculator -- it has a single Yes/No input and two possible outputs, nothing more. Selecting "Yes" sets Illustrative Shift to 1 hour and returns a note describing the standard US pattern: clocks move forward an hour in the spring and back an hour in the fall (lines 4-11). Selecting "No" sets the shift to 0 and returns a note explaining that no US-style shift applies, with a prompt to enter regional rules manually.

There's no year input and no date math anywhere in this tool -- it doesn't compute the specific Sunday in March or November that the shift takes effect in a given year, doesn't look up any particular country's or state's rules, and doesn't know that a handful of US jurisdictions (most of Arizona and all of Hawaii, among others) don't observe the shift at all. It exists to state the one-hour magnitude of the typical US shift as background context for site visitors doing other date and time math nearby, not to serve as an authoritative timezone or scheduling reference. Anyone who needs the exact transition date for a specific year, or needs to know whether their own region observes the shift, has to check that separately -- the calculator's own note says so directly, telling the reader to verify local law rather than treating its one-hour figure as universally applicable.