js2

@keyframes tranzitie {
  from {border-color: red;}
  to {border-color: blue;}
}
#container {
  height: 600px;
  width: 600px;
  background-color: #800080;
}

.patrat:nth-child(odd) {
  border: 1px solid black;
  background: #ffff00;
}
.patrat:nth-child(even) {
  border: 1px solid black;
  background: #ffa500;
}

@keyframes tranzitie {
  from {border-color: red;}
  to {border-color: blue;}
}

@media (max-width: 800px) {
  #container{
    width: 50%;
    border: 10px solid red;
    animation-name: tranzitie;
    animation-duration: 1s;
    animation-iteration-count: infinite;
  }
  }
}