[yokuze]

Alternate title: "How to break your website's styling for 10-20% of your users"

This is a nice reference, and some properties like `scrollbar-gutter` can be used for progressive enhancement.

However, many options listed will require some kind of fallback if `autoprefixer`/`postcss`/etc. doesn't cover it, and if you don't want to exclude a large fraction of your users.

It's reasonable in some cases to have both "new" and the old fallback code side-by-side until _your users's_ browser adoption stats indicate that you can delete the old fallback code without breaking a substantial number of users.

But the reality of using the new CSS hotness is that if the code is not supported by a % threshold that is much higher than many of these techniques show, it actually _increases_ your workload in the near term. You write new + the fallback + ensure that they don't interfere with each other.

P.S. Note the emphasis on _your users_ in the paragraph above. Global browser stats are fine as a basic reference, but your specific site/app's userbase demographics affect the actual percentages tremendously. That may mean you can use ALL of these new techniques today, or some, or none of them.

If your audience is primarily software developers, then after measuring you may find you can use these without a fallback. If it includes people in less wealthy communities or countries, or in countries with restricted access to mobile phone markets, you likely cannot.

[socalgal2]

Is it 10-20% of "your users" or 10-20% of the world but <1% of "your users"

[yokuze]

I don't follow. Assuming that the caniuse data is also representative of your users (a big assumption), then it's 10-20% of either group. Adjusting the % for the subset that is "your users" can result in either a higher or lower %.

Let me know if I'm missing something.