Open UI + CSSWG Reading material for Monday

Hello everyone,

Someone asked if there is any content that is worth reading before Monday's
meeting between Open UI and the CSSWG. I'm going to list resources for each
agenda item that will help provide some context to the topics.

Since form controls are so broad and are composite across all parts of the
web platform I have purposefully not done one-off issues to discuss this
topic as I think it's worthwhile to discuss the problem space holistically
and then tackle each area on its own while being level set. This is how the
presentation from Melanie and I will go as we have concrete definitions and
stages that build on one another that will hopefully enable us all to
invest in the right areas to serve our customers best.

   - The problem:
      - Initial thoughts on standardizing form controls
      <http://gwhitworth.com/blog/2019/07/form-controls-components/>
      - Can we please style the select
      <http://gwhitworth.com/blog/2019/10/can-we-please-style-select/>
   - The spectrum of customizability:
      - accent-color form control proposal
      <https://github.com/w3c/csswg-drafts/issues/5187>
      - Should interoperability be a goal for 'accent-color'
      <https://github.com/w3c/csswg-drafts/issues/5480>
   - Fully style-able & extensible:
      - How should full control be toggled?
      <https://github.com/whatwg/html/issues/5791>
      - Enabling custom control UI explainer
      <https://github.com/MicrosoftEdge/MSEdgeExplainers/blob/main/ControlUICustomization/explainer.md>
   - Venue for control definitions

Looking forward to working with you all on Monday!

~Greg