librustdoc: blur page when help dialogue is present

[andreastt]

Blurs the document's background when the help dialogue is present,
making the contents of the dialogue stand out more.

[rust-highfive]

Thanks for the pull request, and welcome! The Rust team is excited to review your changes, and you should hear from @nikomatsakis (or someone else) soon.

If any changes to this PR are deemed necessary, please add them as extra commits. This ensures that the reviewer can see what has changed since they last reviewed the code. The way Github handles out-of-date commits, this should also make it reasonably obvious what issues have or haven't been addressed. Large or tricky changes may require several passes of review and changes.

Please see the contribution instructions for more information.

[steveklabnik]

I like this idea, and think it looks fine, but am terrible at CSS and would like @gankro or @alexcrichton to check it too.

[andreastt]

I’m sure it can be done in cleverer ways. I just realised this patch also fixes the positioning of the dialogue as you scroll. It relies on flexbox, which by now should be available in all major browsers, to centre the box vertically as well as horizontally.

[alexcrichton]

Could you post this on a site to poke around on? Also is this supported in most browsers?

[Gankra]

mind: blown

[nikomatsakis]

Everything I know about HTML and CSS I learned in 1997. r? @alexcrichton

[andreastt]

@alexcrichton

Before:

After:

[alexcrichton]

@bors: r+ 0baadfc34e6afc679043d280a1c6b7b47bf3c8a4

Nice!

[bors]

🔒 Merge conflict

[ftxqxd]

According to caniuse, filter requires a -webkit- prefix to support Chrome (and other WebKit browsers).

[bors]

☔ The latest upstream changes (presumably #26913) made this pull request unmergeable. Please resolve the merge conflicts.

[steveklabnik]

@andreastt needs a rebase :)

[andreastt]

@steveklabnik Just got back from holiday 🌴

[andreastt]

@P1start Thanks, added the prefix!

[steveklabnik]

@bors: r+

[bors]

📌 Commit 6b64826 has been approved by steveklabnik

[steveklabnik]

@andreastt nice, hope you had a good time :)

[bors]

⌛ Testing commit 6b64826 with merge 4e51763...

[bors]

☀️ Test successful - auto-linux-32-nopt-t, auto-linux-32-opt, auto-linux-64-nopt-t, auto-linux-64-opt, auto-linux-64-x-android-t, auto-mac-32-opt, auto-mac-64-nopt-t, auto-mac-64-opt, auto-win-gnu-32-nopt-t, auto-win-gnu-32-opt, auto-win-gnu-64-nopt-t, auto-win-gnu-64-opt