make sure the screen doesn't sleep when the timer is active on mobile

On mobile, when the timer has been activated and it is beeping, the screen will turn off after a minute (per your settings). When the screen turns off, the beeping will no longer be played.

It would be nice to make sure either the screen doesn't turn off after a minute, or the beeping doesn't stop when the screen turns off.

It looks like youtube on mobile is able to make sure the screen doesn't turn off while you're watching something, so hopefully having a web page keep the screen on is something that can generally be done on mobile.

Start by investigating how the mobile web page's timer and beeping behave when the device screen sleeps, using the issue's YouTube example as a reference for keeping the screen awake. Determine whether the desired result is preventing sleep or preserving beeping after sleep. Done means the active timer continues beeping reliably on mobile after the relevant screen-timeout period.

Written by the indexing model from the issue text.