Do CSS functions exist

Question

I'm not sure what to call this, but basically, let's say I have a style that I use a lot,

.somepattern{
    font-size:16px;
    font-weight:bold;
    border:2px solid red;
}

However, occasionally I want to alter the font size and border color. Could I use this code as a library so that I could set the style to a div?

<div class="somepattern">Text</div>

but still, control the 16px and red like we do with functions?