How does CSS work in font without italic?
Think
When the first font I specify doesn't have italic, will the first font be italicized or will the second font with italic be displayed?
Here is a page importing 3 fonts.
Code
<span style=
"font-family: 'Roboto', 'Playfair Display'; font-style: italic;">
This is Roboto first, Playfair Display second. And style is italic.</span>
Now let's see how the above code runs.
Conclusion
Force italics when that doesn't have italics, without displaying the next font.