Controlling size of the plot-container plotly?

I have a grid of individual plots. I want to display them side by side, but the “plot-container plotly” class
extends the width of the plot to 100 % . I have tried to use sublots. but the underlying plots have 4 traces each, which apparently is more than the subplots functions can handle. Plus, these plots (see below) are one element of a multiplot-display, so setting the width of the “plot-container plotly” class in CSS won’t work.
Two questions:
How would one change the width of the “plot-container plotly”?
Is there a way to create a custom container in CSS that I can use to control the width of some of the plots on the page?
A sample image:

This is what I want: