Why can't I just apply a large amount of selectors to CSS script?

Question

I just began learning HTML/CSS a few day ago and I was wondering why a lot of my code that I have been writing recently isn't working properly.

Why can't I simply use many selectors in order to apply all of my desired declarations?

 header nav ul { list-style: none; text-decoration: none; color: black; }

 <header> <nav> <ul> <li><a href="#">Home</a></li> <li><a href="#">About</a></li> <li><a href="#">Blog</a></li> <li><a href="#">Contact</a></li> </ul> </nav> </header>

Answer 1

As zer00ne said, you can target the links in the list because you are now targeting the list. just add a after the ul to do that. here is how.

 header nav ul a { list-style: none; text-decoration: none; color: black; }

 <header> <nav> <ul> <li><a href="#">Home</a></li> <li><a href="#">About</a></li> <li><a href="#">Blog</a></li> <li><a href="#">Contact</a></li> </ul> </nav> </header>