The alignment container is the rectangle that the alignment subject is aligned within. This is defined by the layout mode; it is usually the alignment subject's containing block, and assumes the writing mode of the box establishing the containing block.
align-content propertyalign-items propertyalign-self propertyjustify-content propertyjustify-items propertyjustify-self propertyplace-content shorthand propertyplace-self shorthand propertyscroll-snap-align property