@font-face{font-family:myFont;src:url(css/fonts/myFont.woff);}
@font-face{font-family:myBoldFont;src:url(css/fonts/myBoldFont.woff);}

<style>
.bold{
    font-family:"myBoldFont";
}
</style>
<div class="bold">Hello world</div>

<style>
    strong,h1,h2,h3,h4,h5,h6,h7,h8{
        font-family:"myBoldFont";
        font-weight:normal;
    }
</style>

font-family:"myBoldFont",helvetica,arial,sans-serif;