@RobesPierre

You don't trademark a font, per se. (Well, maybe you do if you are a type designer or foundry selling type fonts themselves, like Helvetica, but I digress).

You trademark a NAME or WORD that indicates a brand, like "Firestone" for tires, or "Zappos" for an online shoe store, or "Phish" for a musical act.

You can just trademark the word itself, OR, if the word is rendered in a unique way, or uses a graphic logo, or even specific colors, like the white and red scheme used by Target Stores or the yellow and red used by McDonalds, you can trademark THAT TOO, as a graphic mark, which is searchable on the US Patent and Trademark database website. The logos are searchable not only by the words, but by categories, such as logos that are abstractions of animals, like the Phish logo which looks like a fish.

NOW, where this is all going is that you can't trademark a "color" or "font" in a free floating manner, like trying to trademark the color yellow so only you can use it.

BUT, let's say you want to sell "Flintstone" tires, and happen to render the word "Flintstone" in the same font as "Firestone". That's probably infringement, because it's obvious that you want consumers to confuse your cheap knockoffs with Firestone tires.

Or you have a hamburger joint named "MacDonahues" and just happen to render that name in Helvetica font and use yellow, red and swooping circles in your store and packaging designs. Probably infringement, even if your name really is MacDonahue.

That's not trademarking a "font" or "color", but it is trademarking the "trade dress" which is associated with the registered mark.

Although the tests are more complicated, the key is whether the challenged use is similar enough to the registered trademark so that some consumers are confused and buy the knockoff thinking it's the real item, or a similar appearing item at a bargain price.