*{
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}
body{
    position: relative;
    background: black url('Imagens/espaco.jpg') center center / cover no-repeat fixed;
}
.container{
    position: relative;
    height: 100vh;
}
.img{
    position: absolute;
    left: 40%; top: 40%;
    transform: translate(-50%,-50%);
    max-width: 300px;
    width: 100%;
}
/* imagem flutuante*/
.img{
    animation: flutuar 10s ease-in-out infinite;
}
@keyframes flutuar{
    0%, 100%{
        transform: translateY(0);
    }
    50%{
        transform: translateY(-120px);
    }

}