It is a text string.
Power is a new add-on and there may not be a translation from old legacy add-ons will not “auto” translate. WPML is not very useful imo for what you are doing, straight text translation.
There is NO CSS WITH POWER. Any ability for CSS or to change appearance, layout etc is part of Experience Add-on
Also the LABEL to be changed, if you wish to put anything in there, including in German, “No results found” ability to change it is under Experience/results/APPEARANCE…and that is part of the Experience add-on not the Power add on..you can put anything in place of No results found, you can type in “HEY Go try again”,
“Try a different search”
…or anything beside No results found. ….
See my attached to see what I put in place of No results found..
But the same deal will apply if you are translating a new add-on, i.e Power, Lance will discuss with you an equitable adjustment. Perhaps he will send you the Experience Add-on, send an email to support with the translation you did for Power.