Italics in Fira

Hex's Lupino Serif, which is what I've set this website in, is a beautiful font—but doesn't have an italics variant just yet. Up until now, I'd just been using the brutal forced italics that browsers display when using font-style: italic, but I wasn't pleased with that solution. Instead, I've chosen to use Fira Sans for the italics, and I'm offsetting it in a jaunty accent colour! Trickier still, I've set the font-size to 1.05em, since Fira is visually just slightly smaller than Lupino. Maybe that's against the rules but it's my website.