How the devil do I describe the font family of FF Tisa, please?
In order to use a custom font like FF Tisa on a WordPress.com blog, first it must be one of the fonts you selected and saved in your Appearance > Customize > Fonts panel.
You cannot load FF Tisa through CSS only, it has to be done through the Fonts panel.
If you've selected FF Tisa as one of the fonts in your Fonts panel, then you could also refer to that font using a font-family rule like this:
You would want to replace YOUR_SELECTOR_GOES_HERE with the proper CSS selector, which you could add in the HTML.
So, if you had this in your HTML:
<span class="mytitle">ONLINE BOOKSTORES</span>
Then you could use a CSS rule like this:
You can change "mytitle" to whatever name you want as long as the names match in both the HTML and CSS.