.high-contrast {
  background-color: black;
  color: yellow;
}

.high-contrast a {
  color: cyan;
}
.high-contrast .card,
.high-contrast .navbar,
.high-contrast footer {
    background-color: black !important;
    color: yellow !important;
}

.high-contrast .btn {
    border: 2px solid cyan !important;
}