> Modify the base font-size to 62.5% so that 1.6rem = 16px.

Would you consider removing this?

Of course! I took this idea from the milligram project [1], but if you feel like it is a downside I am open to hearing your arguments. Feel free to open an issue [2] so we can discuss it.

[1]: https://github.com/milligram/milligram/blob/master/src/_Base...

[2]: https://github.com/louismerlin/concrete.css/issues/new