@KrzysztofLeczycki
Posted
Hi,
The fIrst of all don't duplicate id atributes in your tags. Each id shall be unique.
This code snippet: body {width: 90rem;}
spoils your layout. Just remove it.
By the way I think using percentage or view units for setting dimentions of the block elements is more comfortable than rem.
You could use minmax function, auto-fit or more media queries to improve responsivness of your grid.
Best wishes. :D