How do I force Chrome to print a web page in portrait mode?

Question

How do I force Chrome browser to print this web page in portrait mode? It doesn't have an option to select the orientation! When I select "Print using system dialog..." it still prints in landscape mode. I wish to print it in portrait mode and scale the size down so it fits. I will do it manually, but the orientation option does not exist. I even tried printing to FoxIt PDF Writer but it still comes out in landscape mode.

https://ocw.mit.edu/ans7870/SP/SP.236/S09/lecturenotes/drugchart.htm

Solution

Open the Developer Tools (Ctrl+Shift+I).
Go to Sources and open drugchartstyle05.css.
Go to line 91 and change the word landscape to portrait.