.header-background() { background: fade(@header-bg, 98%); position: fixed; top: 0; left: 0; right: 0; z-index: @zindex-header; border-bottom: 1px solid @control-bg; .transition(~"box-shadow 0.2s, -webkit-transform 0.2s"); @media @phone { height: @header-height-phone; } @media @tablet-up { height: @header-height; } }