.day {
    border-radius: 10px;
}

body{/*背景图片设置*/
    background-image: url("https://images.cnblogs.com/cnblogs_com/xiefengze1/1100456/o_Tachibana%20Kanade_000000.png");
    background-repeat: repeat;
    background-attachment: fixed;
    background-size:cover;
}