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GitHub project “csswg-drafts”

Hole in CSS rendering model: initial and transitional page paints

on (ttk.me b/4zE1) using BBEdit

Browsers currently paint a window with a default background before/while loading web pages, CSS, and other resources. This happens both upon opening a new window with a URL (initial paint), and when navigating from one page to another (transitional paint), and is currently unspecified by the CSS rendering model.

This hole in the CSS rendering model results in proposals to use meta tags instead, such as viewport, and potentially for a dark mode.

I pointed this out in the discussion on Issue 3299 in the afternoon of 2019-02-26 at the CSSWG meeting.

Rather than awkwardly punting this area of rendering behavior(s) to an HTML meta tag or other non-CSS solution, CSS should define how browsers should (or at least may) render initial and transitional paints, preferably with a feature that permits author control, especially (at least) between pages of the same origin.

Prior related work:

Anything specified in the CSS rendering model for handling initial and transitional page paints should reference the HTML specification and hook into the DOM and states described in: HTML Standard: 7.7 Session history and navigation.

Labels: Needs Thought, unknown/future spec