index.css

@keyframes example {
    0%   {left:0px; top:0px;}
    25%  {left:200px; top:0px; transform: rotate(90deg);}
    50%  {left:200px; top:200px; transform: rotate(180deg);}
    75%  {left:0px; top:200px; transform: rotate(270deg);}
    100% {left:0px; top:0px; transform: rotate(360deg);}
  }

@keyframes color_change {
    0% {color: red;}
    10% {color: blue;}
    20% {color: orange;}
    30% {color: yellow;}
    40% {color: green;}
    50% {color: purple;}
    60% {color: pink;}
    70% {color: skyblue;}
    80% {color: blueviolet;}
    90% {color: greenyellow;}
    100% {color: brown;}
}

#the_cat {
    position: relative;
    animation-name: example;
    animation-duration: 4s;
    animation-iteration-count: infinite;
    animation-timing-function: linear;
}

#welcome {
    animation-name: color_change;
    animation-duration: 1s;
    animation-iteration-count: infinite;
    
    font-size: large;
}