Make it easier to use the Design System to create non GOV.UK services

[timpaul]

What

Make it easier to adapt the GOV.UK Design System and GOV.UK Frontend for use by services that aren't on GOV.UK.

Why

We know that there are many teams in government who are building services that could use our work but that don't look like GOV.UK, including:

• admin and case working systems
• intranets
• local authority websites

All new public services must comply with WCAG 2.1 by September 2019, including those that aren't on GOV.UK. The Design System will be WCAG 2.1 compliant, so by making it easier for these teams to adopt we're helping them comply with the law.

Stories

• Use !default variables in components to allow easier overrides #1159

• Make it possible to override or remove the Crown logotype from the header
  

[rinto-cyriac]

This is an interesting topic to us as we are in the process of adopting gds design system to make our services work better.

[hannalaakso]

A few more related issues:

• Provide guidance around using the header for non GOV.UK contexts #1174
• Add guidance on changing the font and colours #1019

[hannalaakso]

Also as raised by @RosieClayton, we should look at linking to https://www.gov.uk/service-manual/design/making-your-service-look-like-govuk#if-your-service-isnt-on-govuk more prominently (currently only linked to from Fonts)

[stevenjmesser]

Would want to get @36degrees's opinion on the effort involved with maintaining an unstyled version of the design system.