.login-background{background:linear-gradient(120deg,#8e44ad,#3498db,#f39c12,#e74c3c);background-size:300% 300%;animation:colorChange 15s ease infinite}@keyframes colorChange{0%{background-position:0 50%}50%{background-position:100% 50%}to{background-position:0 50%}}