.success, .warning, .error, .info {
    background-position: 10px 10px;
    background-repeat: no-repeat;
    margin-bottom: 20px;
    padding: 7px 10px 7px 45px;
    border-radius: 5px 5px 5px 5px;
    box-shadow: 0 0 4px #555555;
    font-weight: bold;
    line-height: 1.5;
}

.success {
    background-color: #6DC750;
    border: 0 none;
    color: #113305;
    text-shadow: 0 1px 0 #8CE56E;
    background-image: url("../icon/successM.png");
}

.info {
    background-color: #6C9FD9;
    border: 0 none;
    color: #101436;
    text-shadow: 0 1px 0 #96BDD9;
    background-image: url("../icon/infoM.png");
}

.error {
    background-color: #DD3636;
    border: 0 none;
    color: #590606;
    text-shadow: 0 1px 0 #FF7373;
    background-image: url("../icon/errorM.png");
}

.warning {
    background-color: #F2D86D;
    border: 0 none;
    color: #594300;
    text-shadow: 0 1px 0 #FFF2BF;
    background-image: url("../icon/warningM.png");
}

Quelle: www.freidenkerforum.net