I want to expand div parent with child div but I don\'t know if that\'s possible and how to do it.
You cannot use % and expect box to overflow, else it never ends 100% turns 120%, but then 120% of 120%, becomes .. and so on. forget this idea, it cannot work.
Your CSS request is incoherent.
Beside, to see an element to grow wider than window, one of the parent must be able to behave this way, mostly , content overflow and remain visible. (html/body or parent)
as far as i know only:
display:
table
inline-table
table-row
table-cell
Can let container grow as much as content does.