.mt-20 {
    margin-top: 20px;
}
.mb-20 {
    margin-bottom: 20px;
}
.mt-40 {
    margin-top: 40px;
}
.mb-40 {
    margin-bottom: 40px;
}
.mt-60 {
    margin-top: 60px;
}
.mb-60 {
    margin-bottom: 60px;
}
.mt-80 {
    margin-top: 80px;
}
.mb-80 {
    margin-bottom: 80px;
}