Is there any way to get my "slashes" to be the same size as the Font

I am using a Gotham font, if you go to this website: http://fctrs.com and see the "//Value section header you will see that the "// is a larger height than the text.

I am using this CSS:

.section .subheading
{
    font-family: "Gotham Bold";
    font-size: 130px;
    color: #c12330;
    text-transform: uppercase;
    margin-bottom: 10px;
    margin-right: -12px; /* offset letter-spacing */
    /*line-height: 1em;*/
}


    .section .subheading.left-slashes:before
    {
        letter-spacing: -35px;
        margin-right: 30px;
        content: "//";
    }

I would like the "//" to be the same height as the "Value" text.

Should I consider this a Font issue? My "Gotham Bold" Font asset is delivering the "//" to be a different height than that of AlphaNumberic characters in the Font asset?

I am trying to emulate this PSD capture: