Steps to reproduce
- Open an invalid short URL on a mobile device (e.g., https://w.wiki/qwerty).
Actual result
- You get an unreadably tiny error message in the upper left corner, otherwise a huge white space.
Expected result
- The error message is of readable font size, at the cost of seeing less blank screen. This can be achieved with a viewport meta tag in wfHttpError (rMW includes/GlobalFunctions.php:1557-1585 (at da18f3eea7c2)).