Magento Email Templates Font Face

Question

How can I use my custom font-face in magento email templates?

I use the next codes:

     @import url('https://fonts.googleapis.com/css?family=Roboto');

And

     @font-face {
           font-family: 'Roboto';
           font-style: normal;
           font-weight: 400;
           src:url(https://fonts.gstatic.com/s/roboto/v18/ek4gzZ-GeXAPcSbHtCeQI_esZW2xOQ-xsNqO47m55DA.woff2) format('woff2');
           unicode-range: U+0460-052F, U+1C80-1C88, U+20B4, U+2DE0-2DFF, U+A640-A69F, U+FE2E-FE2F;
    }

But in gmail no head or styles tags appears and I can´t use the font.

Thanks in advance!