header{
position: fixed;
top: 0;
left: 0;
width: 100%;
height: 80px;
background: rgba(0,0,0,.2);
backdrop-filter: blur(15px) !important; 
-webkit-backdrop-filter: blur(15px) !important; 
z-index: 99;
}
header .logo{
height: 40px;
margin: 20px 0;
}
header .logo img{
height: 100%;
}
header .account-section {
float: right;
}
header .btn-header {
margin: 22px 0;
line-height: 20px;
border: 2px solid #ffffff;
padding: 6px 10px;
border-radius: 7px;
background: rgba(255,255,255,1);
color: #000000;
transition: .3s;
}
header a:nth-child(2) .btn-header {
margin-left: 10px;
}
header .btn-header:hover{
background: rgba(255,255,255,.8);
}
#background {
position: fixed;
top: 0;
left: 0;
margin-top: 80px;
width: 100%;
height: calc(100% - 80px);
background: #000000;
}
#background .bg-img {
opacity: .5;
}