Tiny huntsman found in Czechia?
The spider in question is actually Xysticus Cristatus, also known as the common crab spider.

From Wikipedia:


  The adult female reaches a length of 8mm and the smaller male 5mm. The colour varies from light cream, dark brown to greyish with a dark triangle on the carapace which ends in sharp, defined point. The abdomen has a broad middle band fringed by two darker rows of triangular marks which extends back to about two thirds of the carapace length from the posterior row of eyes. ... Active adults have been recorded from February to December, with a peak of male activity in May and June. ... The species has a Palearctic distribution, being found throughout Europe, including Iceland.


Arachnology.cz provides several photos of the species. The image below is a perfect match.

Copyright by Rudolf Macek; published at https://www.arachnology.cz/druh/xysticus-cristatus-800.html; page viewed in May 2019