<!DOCTYPE html> <html> <head> <title>Test mpadded</title> </head> <body> <math> <mpadded mathbackground="red" width="100width"> <mphantom> <mtext style="font-family: monospace">X</mtext> </mphantom> </mpadded> </math> <br> <math> <mpadded mathbackground="red" width="100width"> <mphantom> <mtext mathvariant="monospace">X</mtext> </mphantom> </mpadded> </math> </body> </html>