This cant be done only through customizing the CSS.
I had exactly similar requirement few days back and below is the solution I had used (although it requires changes in core but that was the compliance need of the client )
You will have to use jquery and will have to focus on click event (on finish review link). If you want to bring images also then you can focus on "onload" event. For PDF generation, I had used JsPDF tool (there are others too).
Note :- You will have to change the page refresh time in both the events (if page will get refreshed in between then you will get only half of the PDF, if you want to download right away then it will not be required).