.mb-20 {
    margin-bottom: 20px;
}

.mt-20 {
    margin-top: 20px;
}

.mr-10 {
    margin-right: 10px;
}

.mr-20 {
    margin-right: 20px;
}

.tips {
    color: #999;
    font-size: 12px;
}

input[type='checkbox']{
    vertical-align: middle;
}