这里设置两种背景图片，一张图片在顶部，一张在底部，蓝色渐变

background: url("../img/background/bg-bottom-page.png") no-repeat bottom center ,
    url("../img/background/bg-top-page.png") no-repeat top center, linear-gradient(#0261E5, #0047A1);
    background-size: 100% auto, 100% auto, 100% 100%;