:root{--screen-height:calc(var(--vh) * 100)}#app,body,html{height:var(--screen-height);width:100%;overflow:hidden;margin:0;background:orange}#app{font-family:Avenir,Helvetica,Arial,sans-serif;-webkit-font-smoothing:antialiased;-moz-osx-font-smoothing:grayscale;display:grid;grid-template-rows:auto 1fr auto;background:red}header{height:32px;background:#00f}main{background:green}footer{height:48px;background:#00f}