body {
    background: rgba(10, 90, 120, 1) url('https://images.cnblogs.com/cnblogs_com/blogs/769587/galleries/2224577/o_220930113525_966EE898FEF41F179F84A9186CAD50DB.jpg') fixed no-repeat;
    background-position: 50% 5%; 
    background-size: cover;
    opacity:0.85
}