I have an example setup here: https://www.iq-mag.net/dfp.php
So - leaderboard advert is 900px wife for any screen size over 768px, otherwise it reverts to an advert 456px wide.
So far, so good.
However, on a screensize (mobiles) of anything greater than 456px wide, there is a lot of white space. On anything less, there is scrolling.
I've been reading up about the
fluid ad size a little and was wondering whether it was something I could use here? If not, is there any solution in Google DFP to get the advert below a 768px breakpoint to display full width?