Usually we define one css class to one html element. So it gets all style from that css class.
<h1 class="headfont">your text here</h1>
But sometimes we need more than one style to be applied to a html tag. This is how you can do it …
<h1 class="headfont specialheader">your text here</h1>
‘headfont’ and ‘specialheader’ are two css classes.
You can define any css classes like this.