:root{
    --animation-speed:15s
}
*{
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}
body{
    background-color: rgb(0, 255, 30);
    display: flex;
    justify-content: center;
    align-items: center;
    min-height: 1000vh;
    font-size: 35px;
}
a{
    display: block;
    background-color: white;
    color: black;
    text-decoration: none;
    padding: 15px 20px;
    transition: color 0.3s linear, background-color 0.3s linear, transform 0.1s ease-in;
}
a:hover{
    color: white;
    background-color: black;
    transform: scale(2);
}

@keyframes movearound{
    0%{
        left: 10px;
        top: 10px;
    }
    25%{
        left:calc(100vw - 110px);
        top: 10px;
    }
    50%{
        left:calc(100vw - 110px);
        top: calc(100vh - 110px);
    }
    75%{
        left: 10px;
        top: calc(100vh - 110px);
    }
}

div{
    border-radius: 50%;
    width: 100px;
    aspect-ratio: 1;
    background-color: rgb(255, 0, 0);
    position: fixed;
    left: 10px;
    top: 10px;
    animation-name:movearound;
    animation-duration: var(--animation-speed);
    /* animation-delay: 5s; */
    animation-iteration-count: infinite;
    animation-direction: alternate;
    animation-fill-mode: both;
    transition: all 200ms linear;
}

div:hover{
    animation-play-state: paused;
}

div.square{
    border-radius: 0;
    background-color: blue;
}