using CSS on Product Description

Can we implement CSS code on HTMLarea for our product description page of our product? Thank you very much.

Best Regards,
WEndy

Unfortunately not
You would have to include it inline

What do you mean by inline?

Can somebody help me on this?

If you want to do CSS styling on product description content, you have two choices: you can put it inline in the element concerned, or you can give the element a class or id and style that in your stylesheet. Inline styling can be infinitely tailored to the particular element, but you need to repeat it for every element that has the same styling.
The stylesheet can apply as widely or narrowly as you desire depending on the classes or ids you create, but you do need to go edit the stylesheet before you see the effects.

You can do things like
[inline:]

or

[in stylesheet:]
.myPara {width: 15em; background: #aabbcc; font-size: 1.3em;}

If you apply a "myPara" class to all relevant product paragraphs, and later decide you want them a bit smaller, you can edit once in the stylesheet and they will all change. If you do inline styling, you will have to edit every single product that has that paragraph.

Thank you very much. Now I know what to do.