The offending css is

.content ul {
list-style: square inside;
}

Can we fixed by switching to

.content ul {
list-style: square;
}

I'm not sure if there is a good reason to do "inside" but I'm also wary that the template is making a huge assumption about how it is going to be rendered..

@Jdlrobson no reason. Let's fix this by removing inside

@Jdlrobson actually wait... there's a reason.

we need "inside" to keep the UL's inside the page padding. i think the problem is also having a DIV inside LI

can we do something like li > div { display:inline-block; } instead?

I've asked on the talk page whether we can apply inline-block directly to the template:
https://en.wikipedia.org/wiki/Template_talk:Legend#display:_inline-block_for_mobile_support

Not done, as that would break existing uses depending on block mode. But I note that there already was a https://en.wikipedia.org/wiki/Template:Legend_inline, so I have switched the uses of the Seamonkey article to that version.