wgMFMobileMainPageCss is being used by Hindi and Russian Wikipedia. It was originally added for a specific campaign in Hindu Wikipedia and was never meant to be permanent. It was later adopted in T195905.
This config flag adds an unnecessary ResourceLoader module that applies styles in MobileMainPage.css to the main page.
This expensive config variable seems to serve one purpose
```
.page-Main_Page #content {
background-image: linear-gradient(to top, #ffffff, #eaecf0);
}
```
on Russian Wikipedia this CSS rule seems to be disabled at desktop resolutions and accompanied by a rule to disable box-shadow on the header:
```
.page-Main_Page .header-chrome { box-shadow: none; }
```
I propose we drop this module. 1 less ResourceLoader (1 small step for performance) and 1 less PHP class.
Existing pages:
* [[ https://hi.m.wikipedia.org/wiki/%E0%A4%AE%E0%A5%80%E0%A4%A1%E0%A4%BF%E0%A4%AF%E0%A4%BE%E0%A4%B5%E0%A4%BF%E0%A4%95%E0%A4%BF:MobileMainPage.css | Hindi ]]
* [[ https://ru.m.wikipedia.org/wiki/MediaWiki:MobileMainPage.css | Russian ]]
= Acceptance criteria
[] Check in with @alexhollender about the appropriate behaviour here - box shadow or no box shadow
[ ] Move content specific Hindi styles to TemplateStyle applied to MainPage scoped to body.skin-minerva - I can do this using staff account if given permission.
[] Add the new required rules to the existing module skins.minerva.mainMenu.styles - configurable if necessary.
[] Ensure Russian Wikipedia are aware of this change so they can make adjustments if they want to.
[] Drop code from MobileFrontend
[ ] Drop the config flag.