AlexG88,
<style>
.n{color:black}
.y{color:red}
</style>
<select class="n" onchange="className=selectedIndex?'y':'n'">
<option class="n" value="">Select with few options</option>
<option class="n" value="apple">Apple</option>
<option class="n" value="banana">Banana</option>
<option class="n" value="orange">Orange</option>
</select>