div {
    text-align: center;
}

img { 
    padding: 3px;
    border: 2px solid black;
}

.animal1 {
   background-color: gray;
}

.animal2 {
   background-color: beige;
}

.animal3 {
    background-color: lightslategray;
}

@media screen and (min-width: 300px) and (max-width: 480px) {
    body {
        background-color: black;
        color: white;
    }
}

@media screen and (min-width: 700px) {
    div {
        float: left;
    }
}