@valcio Hey there, sorry we missed this.

Could we strongly recommend that you limit this to logged in users as an opt-in gadget for now or at least limit it to an opt-in class e.g. wikitable-blend-background that editors have to add explicitly to tables to mark as safe to apply this rule to?

While this gadget may be helpful on pages such as https://it.m.wikipedia.org/wiki/UEFA_Nations_League_2024-2025?vectornightmode=1&minervanightmode=1 this kind of gadget can be pretty dangerous on certain tables and harm the article content. @Jdlrobson describes why shortcuts are a bad idea in this blog post:
https://jdlrobson.com/posts/2024-07-09_dark-mode-s-bright-future#5e39

To give some Italian specific examples that illustrate the point:

• In https://it.wikipedia.org/wiki/Elezioni_presidenziali_negli_Stati_Uniti_d%27America_del_1964 the colors of the Republican and Democratic party are too faint to be readable which impacts the ability to read the page. In https://it.wikipedia.org/wiki/Elezioni_politiche_in_Italia_del_2022#Partiti,_movimenti_e_gruppi_politici when there are more parties the information is not only unreadable but factually incorrect - particularly where the images correspond to table rolws.
• It breaks the swatch at the bottom of the page on https://it.wikipedia.org/wiki/Arancione_internazionale

We are also a little worried about performance, so we would like to create time to investigate those background-blend-mode: multiply; rules to ensure they are not negatively impacting SEO and user performance.

If changing the gadget requires more community discussion, we can do a deployment tomorrow to roll back dark mode support from anonymous users as a temporary measure. Let us know which you prefer.

Thanks @Sannita.

This gadget follows a community discussion (here) so it would probably be better to ask there for an opinion.

Honestly I would’nt to rollback anything, I’d just wait for you to verify the background-blend-thing.

Also, please notice that while it is true that in some cases colors don’t work well, without the gadget enabled the situation is much worse and much less accessible.

Hey there, we need some time to verify the impact of this change, so for now we've disabled dark mode for anonymous users.

Marking as 2 points as this should give the information we need (running a synthetic test and write up). Proposing as a low priority spike for sprint 5.

Focusing purely on the code and ignoring the issue which has already been pointed out that this gadget distorts many colors and isnt a long term fix to the few tables that are improved by this gadget:

I ran some synthetic tests using sitespeed.io on a page containing some colored tables comparing with and without the gadget
There's a clear negative performance impact from the gadget, although its not a huge increase. This amount could increase if there are more elements on the page where the filter is being applied.
From a code review perspective, the CSS adds quite a few highly specific selectors, which also isnt ideal and adds extra bytes of CSS.

This is with the gadget (overall score of 81)

The gadget is now opt-in only (diff). Please enable dark-mode back for unlogged users. Thank you.

Change #1101573 had a related patch set uploaded (by Jdlrobson; author: Jdlrobson):

[operations/mediawiki-config@master] Expand support for dark mode for anonymous users (itwiki, enwikivoyage)

https://gerrit.wikimedia.org/r/1101573

Change #1101573 merged by jenkins-bot:

[operations/mediawiki-config@master] Expand support for dark mode for anonymous users (itwiki, enwikivoyage)

https://gerrit.wikimedia.org/r/1101573

Mentioned in SAL (#wikimedia-operations) [2024-12-09T21:34:54Z] <cjming@deploy2002> Started scap sync-world: Backport for [[gerrit:1101573|Expand support for dark mode for anonymous users (itwiki, enwikivoyage) (T379352)]]

Mentioned in SAL (#wikimedia-operations) [2024-12-09T21:38:44Z] <cjming@deploy2002> jdlrobson, cjming: Backport for [[gerrit:1101573|Expand support for dark mode for anonymous users (itwiki, enwikivoyage) (T379352)]] synced to the testservers (https://wikitech.wikimedia.org/wiki/Mwdebug)

Mentioned in SAL (#wikimedia-operations) [2024-12-09T21:46:02Z] <cjming@deploy2002> Finished scap sync-world: Backport for [[gerrit:1101573|Expand support for dark mode for anonymous users (itwiki, enwikivoyage) (T379352)]] (duration: 11m 08s)

I have restored dark mode on Italian Wikipedia for anonymous users now that the gadget has been made opt in.