.book .book-body .page-wrapper .page-inner section.exercise {
    display: block !important;
    padding: 0px;
    margin: 20px 15px;
    border: 3px solid #2f8cde;
    background: #fff;
    color: #333;
    font-family: sans-serif;
}

.page-inner section.exercise .header {
    padding: 5px 15px;
    color: #fff;
    background: #2f8cde;
}

.page-inner section.exercise .header h2 {
    margin: 0px;
    font-size: 20px;
}

.page-inner section.exercise .message {
    margin: 5px 15px;
}

.page-inner section.exercise .editor {
    min-height: 50px;
    font-size: 14px;
    border-top: 1px solid #ddd;
    border-bottom: 1px solid #ddd;
}

.page-inner section.exercise .alert {
    display: none;
    margin: 0px;
    margin-bottom: 10px;
    padding: 8px 15px;
}

.page-inner section.exercise.return-error .alert-danger {
    display: block;
}

.page-inner section.exercise.return-success .alert-success {
    display: block;
}