Bugzilla

One clarification on STR:
> Trigger the "Find in page" function of the browser and close it.

More specifically:
* Trigger the "Find in page" function
* ...and then **tap the downarrow at the bottom left of the keyboard**.  (do not close the find-in-page UI.)

With that clarification, I can reproduce this issue.  I think this is a case where we're still setting aside space for the navbar (subtracting that away from the fixed-position viewport.

DIAGNOSIS NOTES:
Both elements here have `position:fixed; bottom: 0;` styles applied to them, and when you scroll down, the site adds a dynamic vertical offset to each of them, **intending to shift them fully offscreen**[1].  But because we're setting aside space for the navbar (or something like that) and pushing fixed-position elements inwards, they don't actually make it all the way offscreen.

The fact that they overlap isn't actually a bug -- that's by-design, as far as I can tell -- but you're not supposed to be able to see that they're overlapping, because the **position-at-which-they-are-overlapping is supposed to be offscreen**.

[1] e.g. for the `<action tray>`, the site shifts it offscreen by giving it `transform: translateY(72px)` (which is 1 more than its `height:48px` plus `padding-bottom: 23px`, which should make its content-box be fully off-screen).

And for the `<mobile-footer>`, the site overrides `bottom:0` with `bottom: -50px`, which is more than enough to scroll it entirely offscreen (it's only ~20px tall for me).

One clarification on STR:
> Trigger the "Find in page" function of the browser and close it.

More specifically:
* Trigger the "Find in page" function
* ...and then **tap the downarrow at the bottom left of the keyboard**.  (do not close the find-in-page UI.)
* (or, just try to scroll the page, which also dismisses the keyboard)

With that clarification, I can reproduce this issue.  I think this is a case where we're still setting aside space for the navbar (subtracting that away from the fixed-position viewport.

DIAGNOSIS NOTES:
Both elements here have `position:fixed; bottom: 0;` styles applied to them, and when you scroll down, the site adds a dynamic vertical offset to each of them, **intending to shift them fully offscreen**[1].  But because we're setting aside space for the navbar (or something like that) and pushing fixed-position elements inwards, they don't actually make it all the way offscreen.

The fact that they overlap isn't actually a bug -- that's by-design, as far as I can tell -- but you're not supposed to be able to see that they're overlapping, because the **position-at-which-they-are-overlapping is supposed to be offscreen**.

[1] e.g. for the `<action tray>`, the site shifts it offscreen by giving it `transform: translateY(72px)` (which is 1 more than its `height:48px` plus `padding-bottom: 23px`, which should make its content-box be fully off-screen).

And for the `<mobile-footer>`, the site overrides `bottom:0` with `bottom: -50px`, which is more than enough to scroll it entirely offscreen (it's only ~20px tall for me).