<div class="alert">.alert</div>
    <div class="alert alert-serious">alert alert-serious</div>
    <div class="alert alert-error">alert alert-error</div>
    <div class="alert alert-warning">alert alert-warning</div>
    <div class="alert alert-success">alert alert-success</div>
    <div class="alert alert-reminder">alert alert-reminder</div>
    <div class="alert alert-gloomy">alert alert-gloomy</div>
    <div class="alert alert-pretty">alert alert-pretty</div>