Adding fonts to Numbers

Is it possible to use downloaded fonts in Numbers on iCloud.com? I have a MacBook, but our home computer is a PC. I like to use the PC for several things, and it's super convenient to be able to use Numbers online. The only thing that's making me sad is that it doesn't seem like there is a way to use fonts that I have downloaded. Nothing against the fonts in Numbers, but I really like my fonts! Clearly I can use the fonts I want on my MacBook, but when I open the spreadsheet, the fonts don't transfer even though they are downloaded on both computers. Am I missing something?