Adding extra heading to product description

Site URL: https://www.madleennilsson.com/

Hi,

Does anyone know how to add an extra heading within the product description? See the attached image.

I've added the product title to the product description assigning it H3. But I had to change the settings of H3 to make it work on other places where H3 is assigned. And I now would like to adjust the Product title solely, without affecting any text elsewhere. I don't want to solve this problem making the standard product title visible since I don't like the placement that gives the Product title on mobile view (on top of all the images and not together with the rest of the product information).

Is it possible to add an extra heading, like H5, in the product description? (I'm using the other heading elsewhere including H4.) 

Thankful for advice.

.ProductItem-details-excerpt h3 {
    color: red;
}

Even better! Thank you rwp!