We had two issues which were present for a long time I think:
- one that impacts both core discourse and chat. We were not setting top on the header when `footer-nav-ipad` was present, meaning that you could make it scroll under if you try to scroll up by putting your finger on the discourse header
- one that impacted only chat. It's also present in core, but in core it's not a probem because we don't have a fixed height div. The body height was higher than the screen which would cause a second scrollbar to appear and would slightly break layout, if you scroll on this scrollbar (body).
Since https://github.com/discourse/discourse/pull/25501 this behavior was broken. This PR attempts to fix it by being more fine grain.
Also note that this PR is moving `footer-nav-ipad` and `footer-nav-visible` to the `html` element and not the `body`. It makes more sense as we are already adding most of other global state class like `keyboard-visible` to the `html` element.
Tested on:
- chrome desktop
- safari ios - iphone
- PWA ios - iphone
- PWA ios - ipad
- DiscourseHub iphone
This commit sets a default of 0px for `--footer-nav-height` and set it only when `body.footer-nav-visible` allowing us to safely use `--footer-nav-height` wherever it will be needed if set.
Float-kit elements (menus/tooltips) are positioned where they should be by setting an inline `left` property in JavaScript when they're rendered. For some reasons, we also set `left: 0` on float-kit elements here:
25d9927785/app/assets/stylesheets/common/float-kit/d-menu.scss (L11-L15)
This property is overridden by the inline property that the library sets in JavaScript. However, in RTL mode, all of our scss files are flipped where everything left becomes right and vice versa. In this case, the `left: 0` property in the scss file above becomes `right: 0`.
This results in a conflict specific to RTL mode where both the `left` and `right` properties are defined on the same absolute-positioned element; the `right` property will always be set to 0 because it comes from the (flipped) scss file above, and the inline `left` property will be set to some px amount determined in JavaScript.
The `right` property will take precedence over the inline `left` property due to the page being right-to-left (source: https://developer.mozilla.org/en-US/docs/Web/CSS/right#description) and this causes float-kit elements to incorrectly always stick to the right.
This commit removes the `left: 0` property altogether for float-kit elements from our scss files. It's not clear from git history why the property was added, and removing it doesn't seem to cause any issues.
Meta topic: https://meta.discourse.org/t/positioning-issues-with-rtl-locales-after-recent-updates/280220?u=osama
