Flex Spacing

Yes, I understand, but the reason behind posting that was to ascertain whoever is reading knows what specifications I was working to avoid any additional ambiguity. 1 year back on some post there was some confusion and when I posted a screencast. Things changed.

Ok.

No No. This is not an extra requirement. 4 columns are not needed. But in case if I am fixing the lefthand sidebar, and putting comment system below Main content + Right handsidebar than this may have this kind of layout:

That nesting of the 2nd part was making things complicated so I was experimenting with something, but not yet successful.

Just below the end of those 3 columns, I put a new flexbox:

Ti match the width of the nested flex(content + Rightsidebar):

/* Comment system */
.commentsystem {
	display: flex;
	max-width: calc(83.33% - 3em);
	flex-direction: column;
	justify-content: flex-end
}

but the flex-end doesnt seems to wok though.

If this would have worked. i would have removed nesting, and made Left sidebar fixed wherever needed.

Margin-left based on %age calculation may work.