Undeline a text within bullet list

Like todays, building navigation menues are built with <ul><li> HTML tags. So usually the CSS defines no bullets like list-style: none;
So I can still use the sitecake bullet list, I have created a user style css class like:

.sc-content  ul.bullet{
list-style-type: disc;
margin: 8px;
padding: 8px;	

}

Now I’d like to underline a single word within a list element. Usually I would code like this : <ul><li>text <u>text</u> text</li></ul>

I wonder how I should just make it so that with a user style it will be doable tu underline a single word. I do not want to use the or tag and assign a class for it because EM and STRONG is used for the intendet purpose.