By way of explanation, I build the top of the page with a stack. Some of the finer points of what I am doing are as follows:
\fboxsep is the border padding of the box around the "M". If positive, the black box gets too wide, so I set it to 0pt. However, to retain an appropriate height to the black box, I make sure to add a
\strut to the box containing the "M".
\noindent keeps the rule from being indented.
\stackalignment says that the stack (in this case, a word under a rule) is right aligned. I used
\def rather than
\renewcommand because I am a lazy typist and saved a few strokes.
the default gap between short-stacked items is 3pt. But I wanted no gap between the rule and the underword. So I used the optional argument
[0pt] to indicate that the stack should be built with no gap between the items.
I enclose the whole construct in its own brace-delimited group, so that parameters like
\stackalignment revert to their prior values when done with the construct.
\bfseries is included immediately after the
\sffamily, the result is this: