header{position:relative;display:flex;align-items:center;width:100%;height:1.4rem;z-index:10;background:#29b3ff}@media screen and (max-width:900px){header{height:.8rem}}header.alternative{position:absolute;top:0;left:0;background-color:rgba(0,0,0,0)}header a img{width:1.5rem;height:auto}@media screen and (max-width:900px){header a img{width:1rem}}