PDF Embed API (inline) issue with fit width

I am using the PDF embed api to embed a number of PDF files using the inline embed mode

While it generally works very well, if the pdf I am embedding is very tall, it no longer expands to fit the width of the page (it will expand only to a particular size, after which it just remains centered).

for an example, see:

https://tcm.school/herbs/resolve_exterior_herbs_testing.html

there are 4 pdfs embedded. If the window is small enough, they all fit the width of the screen, but if the window size is increased, they end up all different sizes. 

Is there a way to force them to all expand to the width of the container they are in?