It is impossible to change the appearance (color status) links using CSS

I can not to change the appearance (color status:link, visited, hover, active) links using CSS.

My code in “style1.css”

a {
font-weight: bold;

a : link {
color: black;

a : visited {
color: gray;

a : hover {
text-decoration: none;
color: white;
background-color: navy;

a : active {
color: aqua;
background-color: navy;

Thanks in advance for the help!

There should be no spaces between the selector and colon and the link state.


a : link{}

Spaces after a selector in CSS represent a descendant selector.