CSS to show values in a treemap

[did]

Using CSS  code (injected via the Multi-KPI-object) I'm trying to force the treemap-object (in Qlik Sense Enterprise on Premise, release Aug 2021 Patch 4)  to show values although by its default definition it shows them only if there is enough space.

If stretched to the whole sheet width my treemap shows the 12 months values like this:

But if I stretch it only to 50% of the sheets width the treemap does not show any values, although there is enough space in each "treemap-cell" to show the respective month value:

I've tried different CSS-code-variations, but nothing worked out.

As far as I understand the CSS should look like this (but something is definitely wrong here):

.qv-object-treemap .qv-object-content {
visibility: visible;
}

My Question: using the CSS via Multi-KPI how to make a treemap-object to show content -values under any size proportions?

Thank you.