class="size-n" in <span> no longer working

[lattemacchiato]

Hi,
in ftui-label, I use e.g.
span slot="unit" class="size-2">m³</span
to show the units in smaller size than the value itself.
I just updated fhem which updated ftui3, but now class="size-2" seems not to be working anymore.
class="size-2" --> BIG font size of unit
class="size" --> same font size of value and unit
size="2" --> no effect on unit.

Obviousely I missed some modifications, or what do I do wrong?

Best,

Paul