#bg{
    background: linear-gradient(rgba(255,255,255,.75), rgba(255,255,255,.75)), url(../img/web-bg.jpg) no-repeat center;
    backdrop-filter: blur(3px);
}

#toubg {
    background: linear-gradient(rgba(255,255,255,.85), rgba(255,255,255,.85)), url(../img/web-bg.jpg) top;
    backdrop-filter: blur(3px);
}