How to extend css class with another style? : <p>I have nearly 30 classes and I want to apply this classes to my button element. I don't want to add class attribute for every button element. Is there any way to create a new button class like;</p>

<pre><code>.button{
        .rounded-corner
        .corner
        .button-effective
        //another 20 classes
}
</code></pre>
