Hi Egnarts,
I deactivated the custom css in JEM's list settings so your override css did work:
However, with a screen size of 1550px width, I don't need the change made by your css:
In this case there is enough space for an ordinary table - for my needs. And imho on a table showing events the data are the most relevant information which should easily be detected. That's why I prefer a separated column showing the data one below each other, rather than a tiny date below some big eye-catching header.
So this leads to the question: how to override an override? I would love to use your css below tablet size and keep mine for big screens. Some @media min-width/max-width switches will certainly help me to achieve this, I understand?
[Off-topic: And since you are German: why didn't you join zip code and city into one row in detail view? Who the hell puts those into two rows in Germany?

]