this task:
this decision 
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Hello @Svitcher
you doing great but there some issue
if you resize the window to smaller area the aside part should be go to the the end of the page and become horizontal like this image
try to resize the output panel in the jsfiddle to notice the behviour when you increase/decrease it
hope that help and have a nice day 
Hello! Thank you very much for your comment 
. I redid the task. New link below.
https://jsfiddle.net/Svitcher/kpLexjvr/16/
Hello @Svitcher
you very welcome and that much better let me give you my humble way
my way that i do not make the user scroll in both way that mean either i make him/her scroll horizontal or vertically to see the whole page not both
when i use the media and screen i would use the px unit as em mean relative size to the parent but here we try to change the layout based on screen size so it not relative to anything except the window size
and have a nice day 
Thank you for help. Have a nice day too.
you very welcome and thanks a lot