How to apply two CSS classes to a single element

Question

Can I apply 2 classes to a single div or span or any HTML element? For example:

<a class="c1" class="c2">aa</a> 

I tried and in my case c2 does not get applied. How can I apply both classes at once?

Answer 1

1) Use multiple classes inside the class attribute, separated by whitespace (ref):

<a class="c1 c2">aa</a> 

2) To target elements that contain all of the specified classes, use this CSS selector (no space) (ref):

.c1.c2 { }