first: popular dot subbox contains the content block of the nearest parent box

the second of these values refers to the inequality that all elements of the content block wrapped in the parent box are not a child element that is not fully filled.

the height of the height of the block box, block box is not the height of the element.
Select the inner element in Chrome, and you can see that the bottom margin is not 1 and extends all the way to the bottom of the outer element. This bottom margin should be the block-level box of the inner element.

come in with a happy face and go out with a confused face

you can get: the containing block of div-sharpinner is the content area of the box generated by div-sharpouter

you can't draw the following conclusion from the above sentence:

since the height of the content area is 200px, the height of the containing block is also 200px

an inclusion block is an inclusion block, and it is not said that it is equal to the content height

the authoritative guide is clearly incorrect (or at least incomplete). Take another counterexample: in the case of, containing block highly fixed and overflow:visible , subblocks can overflow, which is not in line with its statement. Even if the height of containing block is auto , the upper and lower margin can still collapse, which is still not true.

since we refer to the specification, why not read the calculation part by the way, which is much clearer than the book expression.

I think what I'm talking about here is that when
does not set the height of the outer, the height of the outer is calculated from this equation, instead of setting the height first and then forcing the equation to hold.

box-sizing
you need to know about this property
portal