body {
  background: url(../img/bg1.jpg);
  background-size: cover;
  background-position: center;
  background-repeat: no-repeat;
  margin: 0;
  height: 100vh;
  display: flex;
  justify-content: center;
  align-items: center;
}

h3 {
  text-align: center;
}

.card {
  width: 80%;
  max-width: 400px;
  margin: 20px;
  padding: 20px;
  background: rgba(88, 83, 83, 0.18);
  backdrop-filter: blur(2px);
  display: flex;
  justify-content: center;
  align-items: center;
  text-align: center;
  box-shadow: 0 0 10px red;
}

#username:focus,
#password:focus {
  color: rgba(255, 255, 255, 1);
  background: rgba(255, 255, 255, 0.2);
  border-color: rgba(255, 0, 0, 1);
  padding: 5px;
}

@keyframes shake {
}

input.invalid {
  border-color: red;
  animation: shake 0.6s ease-in-out;
}

input.valid {
  border-color: greenyellow;
}

.btn {
  background: rgba(0, 194, 255, 1);
}

a {
  text-decoration: none;
  color: rgba(5, 249, 244, 1);
}

a:hover {
  text-decoration: underline;
  text-decoration-color: rgba(92, 249, 5, 1);
}

.btn:hover {
  background: rgba(0, 255, 45, 1);
  color: rgba(0, 0, 0, 1);
  animation: pop 1s alternate-reverse;
}

@keyframes pop {
}

@media (max-width: 768px) {
  .card {
    width: 90%;
  }
}