[css-align] Content-distribution keywords that fall back to "center" can't be made safe #5088
Description
If you use content-distribution keyword, like "space-between" on a flexbox or grid, and the content overflows the container, it defaults to unsafely centering the content.
But you can't specify safe alignment with a content-distribution keyword! So there' 64AE s just no way for an author to deal with this, except guess at the screen sizes where it might overflow and use an MQ to change it to something safe.
I propose that we specify that the distribution keywords that currently fall back to "center" instead fall back to "safe center".
(If UAs would just implement the "smart" overflow behavior - be unsafe unless it would push content into the unscrollable area - we'd be fine as-is. But nobody's doing that, grrr.)