html,body {

    width: 100%;

    height: 100%;

    filter: contrast(5);

}

​

div {

    position: relative;

    width: 100%;

    height: 100%;

    background: #fff;

    &::before {

        content: "";

        position: absolute;

        top: 0; right: 0; bottom: 0; left: 0;

        background: radial-gradient(#000, transparent);

        background-size: 20px 20px;

        mask: linear-gradient(-180deg, rgba(255, 255, 255, 1), rgba(255, 255, 255, .5));

    }

}