So AFAICS, it looks like Blink simply doesn't apply
line-height to the
According to https://developer.mozilla.org/en-US/docs/Web/CSS/::placeholder:
Only the subset of CSS properties that apply to the ::first-line pseudo-element can be used in a rule using ::placeholder in its selector.
And checking https://developer.mozilla.org/en-US/docs/Web/CSS/::first-line:
Only a small subset of CSS properties can be used with the ::first-line pseudo-element:
- word-spacing, letter-spacing, text-decoration, text-transform, and line-height
So MDN thinks
line-height should work. But trying to chase this down in the W3C specs:
Starting at https://drafts.csswg.org/css-pseudo-4/#placeholder-pseudo:
All properties that apply to the ::first-line pseudo-element also apply to the ::placeholder pseudo-element.
So we check https://drafts.csswg.org/css-pseudo-4/#first-line-styling:
The ::first-line pseudo-element’s generated box behaves similar to that of an inline-level element, but with certain restrictions. The following CSS properties apply to a ::first-line pseudo-element:
- all font properties (see [CSS-FONTS-3])
- the color and opacity properties (see [CSS-COLOR-3])
- all background properties (see [CSS-BACKGROUNDS-3])
- any typesetting properties that apply to inline elements (see [CSS-TEXT-3])
- all text decoration properties (see [CSS-TEXT-DECOR-3])
- the ruby-position property (see [CSS-RUBY-1])
- any inline layout properties that apply to inline elements (see [CSS-INLINE-3])
- any other properties defined to apply to ::first-line by their respective specifications
AFAICT this does not include
line-height, which isn't defined in any of the specs mentioned; it's still defined by CSS2 at https://www.w3.org/TR/CSS2/visudet.html#propdef-line-height. I do wonder if this is an oversight, though, given that
line-height can also be set as part of the
font shorthand, so from that point of view it's covered by the first item here.
In addition, the spec then goes on to say:
User agents may apply other properties as well.
...which leaves things wide open! (But not interoperable.)
Interestingly, a quick test indicates that both Chrome and Safari do support
::first-line; so we might reasonably expect it to work on
::placeholder as well, but the spec doesn't seem entirely clear to me.
Probably worth seeking CSSWG clarification here. Given the behavior of
::first-line (where everyone supports
line-height), and the fact that the spec says
::placeholder supports the same properties, I feel like what we're doing is arguably more correct.