Get rid of political time-zones and DST and simply define 6:00am to be sunrise world wide. Each day starts at 6am and counts from there.

(If you are really brave let the length of the hour vary by latitude so that sunset is always at 6pm as well. In the winter up north the night hours are simply longer than the daylight hours. But this is too enlightened I think.)

We have the tech to do this. The first one is very practical. What time is it? How many hours since sunrise in this location +6?

@futurebird Edo period Japanese clocks had variable hours. There was always the same number of daytime and nighttime hours. Its just the length of the hours changed with the seasons.

And somehow they managed to build mechanical clocks that could do that adjustment which is also impressive