style.css

* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    background: #0F2027;  /* fallback for old browsers */
background: -webkit-linear-gradient(to right, #2C5364, #203A43, #0F2027);  /* Chrome 10-25, Safari 5.1-6 */
background: linear-gradient(to right, #2C5364, #203A43, #0F2027); /* W3C, IE 10+/ Edge, Firefox 16+, Chrome 26+, Opera 12+, Safari 7+ */

}

.container {
    height: 100vh;
    padding: 50px;
}




.button {
    cursor: pointer;
    padding: 10px 20px;
    border: none;
    outline: none;
    border-radius: 5px;
    transition: 0.5s;
}

.button:hover {
    background: cadetblue;
    color: white;
    transform: scale(1.5);
}






.big-box {
    width: 600px;
    height: 300px;
    margin-top: 50px;
    background: cornflowerblue;
    position: relative;
    transition: 1s;
}

/* .big-box:hover .little-box {
    
} */

.big-box:hover {
    background: darkblue;
}

.little-box {
    width: 100px;
    height: 100px;
    background: rgb(130, 84, 238);
    position: absolute;
    animation: move 5s infinite alternate ease-in-out;
}


@keyframes move {
    
    0% {
        top: 0;
        left: 0;
    }
    /* 25% {
        top: 0;
        left: 500px;
    }
    50% {
        top: 200px;
        left: 500px;
    }
    75% {
        top: 200px;
        left: 0;
    } */
    100% {
        left: 500px;
    }

}