6.3 The Almost Standards Mode and CSS2.1
Almost standards mode conflicts with the normative statements found in Chapter 10 of the [CSS-Level2-2009] specification:
In subsection 10.8, the specification states:
In subsection 10.8.1, the specification states:
4. If the resulting height is smaller than the minimal height of line boxes for this block, as specified by the 'line-height' property, the height is increased to be that minimal height. Empty inline elements generate empty inline boxes, but these boxes still have margins, padding, borders and a line height, and thus influence these calculations just like elements with content.
See section 2.1.50.
On a block-level, table-cell, table-caption or inline-block element whose content is composed of inline-level elements, 'line-height' specifies the minimal height of line boxes within the element. The minimum height consists of a minimum height above the block's baseline and a minimum depth below it, exactly as if each line box starts with a zero-width inline box with the block's font and line height properties (what TEX calls a "strut").
See section 2.1.52.
On an inline-level element, 'line-height' specifies the height that is used in the calculation of the line box height (except for inline replaced elements, where the height of the box is given by the 'height' property).
See section 2.1.4.