.required label:after {
    content: ' *';
    color: red;
    font-size: 20px;
    line-height: 20px;
    font-weight: bold;
}
.alert-danger {
    color: #721c24;
    background-color: #f8d7da;
    border-color: #f5c6cb;
}
.alert {
    position: relative;
    padding: 0.75rem 1.25rem;
    margin-bottom: 1rem;
    border: 1px solid transparent;
    border-radius: 0.25rem;
}

.checkbox {
    border: 2px solid #ced4da;
    background: #ffffff;
    width: 22px;
    height: 22px;
    color: #495057;
    border-radius: 6px;
    transition: background-color 0.2s, color 0.2s, border-color 0.2s, box-shadow 0.2s;
}