Create Drop Shadow with CSS code

Creating a Drop Shadow for Text Boxes.

Would anyone familiar w/ CSS codes have a look at my modes 2 line code? I'm doing something wrong and I need help finding it. I've posted the code, no error messages displayed, yet no result shown on my web site.

.image-block {filter: box-shadow (20px 20px 12px #990001);
}

Can you share link to page where you use Text Boxes?