How do I resize a page scraped with cURL?

I have an html page built with Bootstrap, in which there's a panel that occupies 6/12 of the screen size; this panel is in the center of the page, and has a 3/12 panel on each side.
At the same time, I have a cURL and PHP script that scrapes a web page, given a link by the user, and shows it in the panel described above; this script gets all the page content (images, text, code, scripts, etc.) and has (at the moment) the simple task of showing it inside the panel.

Everything is fine about that: the page is showed, and only Google homepage has some problems, related to the complexity of the scripts going on there (and some security measures by Google to prevent phishing and so, I suppose).
The problem is that the page does not fit correctly inside the panel: it starts where it should, but it seems impossible to resize it in order show it all in the panel: it exceeds the right and bottom border.
The only way I know to resize the page is through CSS (applied to the panel content), but it doesn't work; I tried many possibilities (margins, width and heigth, paddings, etc.) but I am unable to make it fit.

I'm beginning to think that I need to add some resize function inside the script, but considering that the user may enter any address, it's kinda impossible to create a specific function to deal with that... do you have any idea?