[csswg-drafts] [website] inaccessible popover

pixelass has just created a new issue for https://github.com/w3c/csswg-drafts:

== [website] inaccessible popover ==
When accessing the page https://drafts.csswg.org/css-transforms/ I see a popover that can only be closed by clicking a very thin lined (X) in the top right corner. 

The ESC button does not close the popover. 
The popover is not accessible via tab navigation.

Aside from that the popover seems to be unrelated to the content I wanted to access.
I used a clean browser in several networks and ran several checks to ensure it didn't come from my computer.

![screen shot 2018-01-23 at 19 46 23](https://user-images.githubusercontent.com/1148334/35294711-8c79b02e-0077-11e8-9451-a37f097f3efd.png)



Please view or discuss this issue at https://github.com/w3c/csswg-drafts/issues/2222 using your GitHub account