assign space for each column in group


while giving the size of each column in the group(have 4 columns) i have used the %, but i don't get it exactly as i like
It says i can use span width..i amtrying to set lke 20px;20px;20px;30Px;
but seems to do not change in strange way
how do i use the span width?and would it be more accurate than percentage?
See your other thread.

In general:
Use your browser dev tools to examine your site, test CSS changes on the fly etc.
i am trying todo it, but i am not that good in html or css....and expecially in joomla
i normally use wordpress and with inspector i can solve manythings as i can add code straight in the backend, don0t need to go and touch the .css or php files
i dont know which one to edit then
SO please be patient, i am helping my wife doctor team to build this questionnaire they use for their statistics with patients
They were using an excel file, one sheet for patient...and was impossibile to get data
If you like to give me a more precise info i'll be really grateful

the most important thing i need, the one that really canmake usable the project is in this topic

how to make the list spread in horizontal and how to put side byside the element filter on top
thank you