Adding text to mobile header

Hi,

I added the name of my company in the header above the navigation and it worked well for the desktop version using 

.header-nav:before {content: "South Mountain Advanced Therapies Consultants, LLC"; display: block; position: relative; top: -20px;font-family:cormorant infant; font-size:18px; white-space:pre}

Since the navigation is different in the mobile version, I am not able to insert the name of the company between the logo and the burger (navigation). How can I accomplish this?

Thank you!

Use this CSS code

div.header-display-mobile .header-title:after {
    content: "South Mountain Advanced Therapies Consultants, LLC";
    display: block;
    font-family:cormorant infant;
    font-size: 11px;
    white-space:pre;
    text-align: center;
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%,-50%);
}

@tuanphan it worked, thank you so much!

My company's name is a bit long (or it will be too small if I make the fonts smaller) and I would like to make it in 2 lines ("South Mountain Advanced" in one line, "Therapies Consultants, LLC" in the next line), how would I accomplish this? 

Thank you!

It worked, thank you so much!