[css-sizing] Percentage sizing section is kind of vague · Issue #1132 · w3c/csswg-drafts (original) (raw)

https://drafts.csswg.org/css-sizing-3/#percentage-sizing

That section is a bit vague. It currently says:

Percentages specify sizing of a box with respect to the box’s containing block.

Although this may require an additional layout pass to re-resolve percentages in some cases, the auto, min-content, max-content, and fit-content values of min-width and min-height do not prevent the resolution of percentage sizes of the box’s contents. However, in order to prevent cyclic sizing in the general case, percentages do not otherwise resolve against indefinite sizes, and instead are treated as auto.

I actually think the text is wrong, in that sizes can only be resolved against definite sizes but the text does not specify that limitation. But beyond that:

• The text implies that max-height can affect percentage resolution of the height (if it is something like min-content), but does not specifically say so
• It seems to imply also that min-content will never prevent percentage resolution of children, but I am not sure that my reading is correct and would appreciate clarification
• It would be nice to clarify that while max-content can prevent percentage resolution of children/descendants, it never affects the value the percentage gets resolved against (that value is always the specified height). OR, if I misunderstood, it would be good to explicitly say so.