css "vertical-align:middle;" does not work correctly

when I use the style( style="vertical-align:middle;") in the html file. which render correct in webbrowser, but not correct in the Qt.

QML project in texteditor.zip. Widget example in qtbug76662.zip.

For example, this does not vertically align the smiley face in Qt:

QLabel lbl("Hello world <span style='font-size: 60pt; vertical-align: middle'>🙂</span> hello world.");
lbl.setTextFormat(Qt::RichText);
lbl.show();