20-20-20 rule timer

While we're still not sure what exactly causes myopia[1], one rule to follow (to try and inhibit myopia progression) that I've heard repeated often is the 20-20-20 rule:

Every 20 minutes, look at an object 20 feet away, for 20 seconds.

I needed an excuse to build something with Svelte[2] version 5, so here we are :)

Note that the 20-20-20 rule is sometimes critized and there might be more effective ways to inhibit myopia. Spending time outdoors, in sunlight, seems to be very important.

Other suggestions[3,4] include spending 5 minutes away from screens (looking at distance) every hour or the "20-20-2-20 rule", which suggests a 20 minute break every 2 hours

[1] https://www.ncbi.nlm.nih.gov/books/NBK470669/

[2] https://svelte.dev/

[3] https://modernod.com/articles/2023-july-aug/myth-busting-the...

[4] https://www.unicef.org/vietnam/stories/20-20-2-20-rule