.feedback {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  background: rgba(220, 53, 69, 0.95); /* bootstrap red-ish */
  color: white;
  padding: 1em;
  text-align: center;
  font-weight: bold;
  z-index: 10000;
  transform: translateY(-100%); /* hidden off top */
}

@keyframes slideBanner {
  0%   { transform: translateY(-100%); opacity: 0; }
  10%  { transform: translateY(0); opacity: 1; }
  90%  { transform: translateY(0); opacity: 1; }
  100% { transform: translateY(-100%); opacity: 0; }
}

.flash {
  animation: slideBanner 3s ease-in-out forwards;
}