calc não funcionou, banner do twitter sumiu

Deixei o trecho comentado porque não deu certo :/

.banner-twitter {
    position: absolute;
    top: 0;
    right: 0;
    line-height: 1;

    -webkit-transform: translate(6.5765em, -2.4745em) rotate(45deg);
            transform: translate(6.5765em, -2.4745em) rotate(45deg);        
    -webkit-transform-origin: 0 0;
            transform-origin: 0 0;


    /*-webkit-transform: translate(calc(0.707 * (3.5em - 100%) + 100%), calc(-.707 * 3.5em)) rotate(45deg);
            transform: translate((calc(0.707 * (3.5em - 100%) + 100%), calc(-.707 * 3.5em)) rotate(45deg);
    -webkit-transform-origin: 0 0;
            transform-origin: 0 0;*/





    width: 14em;
    padding: 1em 0;
    box-sizing: border-box;

    text-align: center;
    text-decoration: none;
    background-color: #3C1D3D;
    color: white;
    border: .25em solid black;

    font-size: 1.2em;
    font-family: "Open Sans Condensed", sans-serif;
}