Additional CSS Classes

Hello,
I am attempting to change the color of the link icon depending on some CSS code. Could you please assist or provide an example of the code I should use?
Thanks,
Erica

Additional CSS classes:
* unvisited link */
a:link {
color: white;
}

/* visited link */
a:visited {
color: #3150c5;
}

/* mouse over link */
a:hover {
color: #3150c5;
}

/* selected link */
a:active {
color: #3150c5;
}* unvisited link */
a:link {
color: white;
}

/* visited link */
a:visited {
color: #3150c5;
}

/* mouse over link */
a:hover {
color: #3150c5;
}

/* selected link */
a:active {
color: #3150c5;
}