CSS背景小方格样式

body:after {
    background-color: #efefef;
    background-image: linear-gradient(90deg, rgba(60, 10, 30, .04) 3%, transparent 0), linear-gradient(1turn, rgba(60, 10, 30, .04) 3%, transparent 0);
    background-size: 20px 20px;
    background-position: 50%;
    background-repeat: repeat;
}

body:after {
    content: "";
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    z-index: -10;
    pointer-events: none;
}