CSS- when do use periods when setting a class

Hi there,

I noticed when I was working on the CSS unit that when you are making some classes (for example body) you do not use a period before:
body{ background-color: brown;}

However when you use other titles for classes, you have to add the period:
.pink-text{color: pink;}

How do you know if you will need to add the period or not before the class?

Thanks :smiley:

If you refer to a tag, you write the name - “body” is a tag, as in <body> ... </body>
If you refer to a class, you write the period - “.pink-text” is a class, as in <p class="pink-text">...</p>
If you refer to an ID (comes later), you write a hastag - “#top-header” is an id, as in <div id="top-header">...</div>

This is great thank you! I don’t think I really solidified the difference between tag, class and ID yet so this is really helpful.