Drop-Shadow Filter on Blockquote

[Yahnah Factor]

I entered the following code for a drop-shadow filter but when I load the file in the browser, it is not showing the shadow around the blockquotes. Can you explain where I made a mistake and why it incorrect?

blockquote {
background: url(sf_speech.png) no-repeat;
background-size: 100% 100%;
filter: drop-shadow(5px 5px 10px rgb(51, 51, 51));
}

[PeterJones]

@Yahnah-Factor ,

See the FAQ