style

body {
    font-family: 'Courier New', Courier, monospace;
}


img {
    width: 300px;
    height: 300px;
    border-radius: 20px;
}


.hover-effect:hover
 {
    opacity : 0.8;
    cursor: pointer;
}


main img:nth-child(3) {
    filter: grayscale(100%);
    -webkit-filter: grayscale(100%);
    -moz-filter: grayscale(100%);
    -ms-filter: grayscale(100%);
    -o-filter: grayscale(100%);
}