Stats graphs could have bigger targets to click on to bring up the popups

Description of your request or bug report:

The graphs on the stats tab of your profile page let you click on the dots to get a little popup that tells you the exact value of the graph at that point (so you can see “oh, I read X pages this month/year”). However the page requires you to click quite precisely on the dot to get the popup, which is tricky on mobile. I often have to zoom in the page to be able to click in the right place, then zoom out again.

I think it would be a nice and hopefully not too tricky UI improvement to enlarge the size of the region the graph accepts as being a click on the dot, so it is easier to do on mobile. (This doesn’t have to change the visual appearance, which seems fine.)

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