How to put scroll bar only for modal-body?

Answer 1

Adding on to Carlos Calla's great answer.

The height of .modal-body must be set, BUT you can use media queries to make sure it's appropriate for the screen size.

.modal-body{
    height: 250px;
    overflow-y: auto;
}

@media (min-height: 500px) {
    .modal-body { height: 400px; }
}

@media (min-height: 800px) {
    .modal-body { height: 600px; }
}