background:url(./img/图片名.png) no-repeat;
background-position:center;
background-size: cover;
overflow:hidden;

html,body{
position: relative;
min-height: 100vh;
width: 100%;
height: 100%;
margin: 0;
background-image: url(../img/图片名.png);
box-sizing: border-box;
background-position: center center;
background-size: cover;
background-repeat: no-repeat;
background-attachment: fixed;
/* overflow:hidden;*/
background-color: rgba(228,228,228,1.00);
display: flex;
justify-content: center;
align-items: center;
z-index: 100;
}