bootstrap-lite modal

.modal {
  position: fixed;
  top: 0;
  right: 0;
  bottom: 0;
  left: 0;
  text-align: left;
  
  z-index: 1000;
  pointer-events: none;
}

.modal-dialog {
  pointer-events: all;
  width: auto;
  max-width: 500px;
  margin-left: auto;
  margin-right: auto;
  margin-top: 1.75rem;
  margin-bottom: 1.75rem;
}


.modal-backdrop {
  background: rgba(0,0,0, .5);
}

.modal.show + .modal-backdrop {
  position: absolute;
  top: 0;
  right: 0;
  bottom: 0;
  left: 0;
  cursor: pointer;
}

.modal.fade .modal-dialog {
  transition: transform .3s ease-out;
  transform: translate(0, -50px);
}
.modal.show .modal-dialog {
  transform: none;
}

.modal-content {
  display: flex;
  flex-direction: column;

  background: white;

  border-radius: .5rem;
}

.modal-header {
  display: flex;
  flex-shrink: 0;
  align-items: center;
  justify-content: space-between;

  padding: 1rem;

  border-top-left-radius:  calc(.5rem - 1px);
  border-top-right-radius: calc(.5rem - 1px);
}

.modal-body {
  position: relative;
  flex: 1 1 auto;

  padding: 1rem;
}

.modal-footer {
  display: flex;
  flex-shrink: 0;
  align-items: center;
  justify-content: flex-end;

  gap: .5rem;
  padding: calc(1rem - .5rem * .5);

  border-bottom-left-radius: calc(.5rem - 1px);
  border-bottom-right-radius: calc(.5rem - 1px);
}

@media screen and (max-width: 768px) {
	
  .modal-dialog {
    width: 90%;
    height: 90%;
    box-sizing: border-box;
  }
}

.fade:not(.show) {
  opacity: 0;
}

.fade {
  transition: opacity .15s linear;
}