Template:Alert/styles.css

.custom-alert {
    padding: 10px 15px;
    margin: 10px 0;
    border: 1px solid #ccc;
    border-radius: 4px;
    background-color: #f9f9f9;
}

.custom-alert-info {
    border-color: #bce8f1;
    background-color: #d9edf7;
    color: #31708f;
}

.custom-alert-warning {
    border-color: #faebcc;
    background-color: #fcf8e3;
    color: #8a6d3b;
}

.custom-alert-error {
    border-color: #ebccd1;
    background-color: #f2dede;
    color: #a94442;
}

.custom-alert-success {
    border-color: #d6e9c6;
    background-color: #dff0d8;
    color: #3c763d;
}