website/css/callouts.css

.caution, .note, .warning {
    padding: 20px;
    margin: 20px 0;
    border: 1px solid #eee;
    border-left-width: 5px;
    border-radius: 3px;
}

.caution {
    border-left-color: #f0ad4e;
}

.note {
    border-left-color: #428bca;
}

.warning {
    border-left-color: #d9534f;
}