<div id="Rojo_Negro">Ejemplo</div>

CSS (1º opción)

<style>

    #Rojo_Negro {
        text-align:center;
        position:relative;
        background-color:#D6A6D4;
        color:#000;
        -webkit-transition-property:background-color, color; 
        -webkit-transition-duration:2s, 2s;
        -moz-transition-property:background-color, color; 
        -moz-transition-duration:2s, 2s;
        -o-transition-property:background-color, color; 
        -o-transition-duration:2s, 2s;
        transition-property:background-color, color; 
        transition-duration:2s, 2s;
    }
    #Rojo_Negro:hover {
        background-color:#A4BBD6;
        color:#FFF;
        -webkit-transition-property:background-color, color; 
        -webkit-transition-duration:2s, 2s;
        -moz-transition-property:background-color, color; 
        -moz-transition-duration:2s, 2s;
        -o-transition-property:background-color, color; 
        -o-transition-duration:2s, 2s;
        transition-property:background-color, color; 
        transition-duration:2s, 2s;
    }
</style>

CSS (2º opción)

<style>

    #Rojo_Negro {
        text-align:center;
        position:relative;
        background-color:#D6A6D4;
        color:#000;
        height:40px;
        width:200px;
        border-radius: 5px; 
        box-shadow: 1px 1px 5px #666;
        border:1px dotted #ffffff; 
        -webkit-transition-property:background-color, color; 
        -webkit-transition-duration:2s, 2s;
        -moz-transition-property:background-color, color; 
        -moz-transition-duration:2s, 2s;
        -o-transition-property:background-color, color; 
        -o-transition-duration:2s, 2s;
        transition-property:background-color, color; 
        transition-duration:2s, 2s;
    }
    #Rojo_Negro:hover {
        background-color:#A4BBD6;
        color:#FFF;
        border-radius: 15px; 
        box-shadow: 1px 1px 5px #666;
        border:1px dotted #000; 
        -webkit-transition-property:background-color, color; 
        -webkit-transition-duration:2s, 2s;
        -moz-transition-property:background-color, color; 
        -moz-transition-duration:2s, 2s;
        -o-transition-property:background-color, color; 
        -o-transition-duration:2s, 2s;
        transition-property:background-color, color; 
        transition-duration:2s, 2s;
    }
</style>