Code for custom font links to desktop fonts instead of Squarespace fonts

I'm trying to do a one-time change for a font on a page. The font is listed in the Squarespace global fonts list, although it is not in the font pack for my template. When I enter the custom CSS code to change the font, it does not seem to link to the Squarespace fonts. If I have the font activated on my desktop, I can see the change. If it is not activated on my desktop, a generic sans serif font appears in the page.

Here is the way I have written the code — I'm intentionally leaving off the block ID in this sample. It is there on my custom CSS code.

* {font-family: montserrat}

Is there any way to write the code so that it will pull the font from Squarespace instead of my desktop?

Thanks for your help!