# Unbolding sans serif font in math mode

Is there a way to "unbold" the default text font (namely, sans serif) when written in math mode? Consider this example:

Hello World$\qquad\textsf{Hello World}$

The first instance of "Hello World" is just plain text; the second is obtained inside math mode using the \textsf command.

You can tell MathJax to use the same font as is used for the surrounding text by the following command:

$\style{font-family:inherit;}{\text{Some text}}$

This gives: $\style{font-family:inherit;}{\text{Some text}}$

This assumes that what you want is to have the same font as the text, which happens to be a sans-serif font at the moment. In case this main font should change in the future or somebody changes it locally via using a custom style-file the text above will also change.

If the intent would be to "force" a sans-serif font, just one that usually is less bold, then this can be done using:

$\style{font-family:sans-serif;}{\text{Some other text}}$

This gives: $\style{font-family:sans-serif;}{\text{Some other text}}$

I learned this from an answer by regret on math.se, and the comments below.

• Or just $\style{font-family:"sans-serif";}{\text{Hello!}}$ to ensure sans serif regardless of the inherited font family. – Asaf Karagila Nov 27 '15 at 22:23
• Strangely it seems not to work $\style{font-family:"sans-serif";}{\text{Hello!}}$ maybe like so $\style{font-family:sans-serif;}{\text{Hello!}}$. // The quotation marks need to go. But thanks regardless. – user9072 Nov 27 '15 at 22:50
• Well, it's not the same sans serif font as used on MO, but it is sans serif. (Both work for me, with the same output.) – Asaf Karagila Nov 27 '15 at 22:52
• No, for me it is a serif-font. I am not sure you saw the updated comment. I think there should be no quotes. – user9072 Nov 27 '15 at 22:54
• On another device it is sans-serif for me too. One more test $\text{Test}$ $\style{font-family:"serif";}{\text{serifquote}}$ $\style{font-family:serif;}{\text{serifnoquote}}$ $\style{font-family:"sans-serif";}{\text{sanserifquote}}$ $\style{font-family:sans-serif;} {\text{sanserifnoquote}}$ Very weird. – user9072 Nov 27 '15 at 23:20
• The standard says (w3.org/TR/CSS2/fonts.html, 15.3) that "generic font family names are keywords and must NOT be quoted", so quid is right. If you put "sans-serif" in quotes, it selects an actual font with this exact name rather than the generic sans-serif font. This happens to work in SOME system configuration (e.g., based on fontconfig) because of the way they implement generic families (namely, by providing a font name alias), but this is unreliable and fails on other systems. – Emil Jeřábek Nov 28 '15 at 9:23
• @EmilJeřábek This explains it nicely. I update the answer a bit. Thanks to both of you for the additional information. – user9072 Nov 28 '15 at 12:35