Decide and document what browsers we support

[hartsick]

Two steps: 1) Decide! 2) Document!

The goal is to help developers decide what CSS & JS features we can use in the future.

Examples from other agencies:

• https://designsystem.digital.gov/documentation/developers/
• https://www.gov.uk/service-manual/technology/designing-for-different-browsers-and-devices

In general, they seem to be: IE 11, but the service shouldn’t break on earlier versions.

Here's a great GDS guide on progressive enhancement: https://www.gov.uk/service-manual/technology/using-progressive-enhancement

[bengolder]

I agree with their standards and I think we should align with them.