Braw mornin' TAG!

I'm requesting a TAG review of the new lv*, sv*, dv*, vi, vb units.

The new units are similar to the existing viewport units (vw, vh), except that they take into account the size of expandable/collapsible browser UI in a few different ways.

• Explainer:
  • This brief article explains it well: https://www.bram.us/2021/07/08/the-large-small-and-dynamic-viewports/
  • Even more brief article which shows the problem with the existing units: https://chanind.github.io/javascript/2019/09/28/avoid-100vh-on-mobile-web.html
• Specification URL: https://drafts.csswg.org/css-values-4/#viewport-variants
• Tests: N/A, unfortunately WPT can't cover the dynamic UI aspects of this.
• User research:
• Security and Privacy self-review: Does not expose new information that's not already exposed via JS.
• GitHub repo: https://github.com/w3c/csswg-drafts
• Primary contacts:
  • @andruud, Google, Working on the implementation in Chromium.
• Organization(s)/project(s) driving the specification: CSSWG
• Key pieces of existing multi-stakeholder review or discussion of this specification:
• External status/issue trackers for this specification (publicly visible, e.g. Chrome Status):

Further details:

• I have reviewed the TAG's Web Platform Design Principles
• Relevant time constraints or deadlines: Q1 2022
• The group where the work on this specification is currently being done: CSSWG
• Major unresolved issues with or opposition to this specification:
  • Not necessarily major nor opposition, but maybe interesting: https://github.com/w3c/csswg-drafts/issues/6551 https://github.com/w3c/csswg-drafts/issues/6453
• This work is being funded by:

You should also know that...

• Safari has recently shipped support for these units.

We'd prefer the TAG provide feedback as (please delete all but the desired option):

🐛 open issues in our GitHub repo for each point of feedback