body{
background:url(https://free4kwallpapers.com/uploads/wallpaper/exploration-wallpaper-2560x1440-wallpaper.jpg);
background-repeat:no-repeat;background-attachment:fixed;background-size: cover;
}
#main{
background-color:rgba(255,255,255,0.5);
}
#mainContent{
background-color:rgba(255,255,255,0.75);
}