Inconsistent margin behavior between margin-captions and sidenotes

[calebqcook]

Describe the bug

When I create a figure with a margin-caption, I notice that the margin-caption -- as compared to a sidenote -- is both:

1. closer to the main text than is the sidenote; and
2. much narrower than is the sidenote.

I also find the typesetting differences between the margin-caption and sidenotes undesirable, as I want the entire right-margin to look consistent, but this is easy enough to fix with some CSS. I have had a harder time (probably given my inexperience with webdev generally) manually rectifying the spacing issues mentioned above.

Reproduce the bug

1. Create a figure directive with several lines of caption text and the following options:

:align: right
:figwidth: 60%
:figclass: margin-caption

2. Create a sidenote nearby.

List your environment

No response