.container{width:1100px;margin:auto}*{padding:0;margin:0;-webkit-box-sizing:border-box;box-sizing:border-box;font-family:'Roboto', sans-serif}header{height:100vh;text-align:center;background-color:#ccc}header #main-nav{background-color:#ddd;height:2rem;line-height:2rem;display:-webkit-box;display:-ms-flexbox;display:flex;-webkit-box-pack:justify;-ms-flex-pack:justify;justify-content:space-between}header #main-nav ul{display:-webkit-box;display:-ms-flexbox;display:flex;text-decoration:none;list-style:none}header #main-nav ul li{padding-right:15px}header .landing{height:100%;display:-webkit-box;display:-ms-flexbox;display:flex;-webkit-box-orient:vertical;-webkit-box-direction:normal;-ms-flex-direction:column;flex-direction:column;-webkit-box-pack:center;-ms-flex-pack:center;justify-content:center;position:relative;background-color:#333}header .landing::before{content:'';background:url(../images/coder.png) no-repeat top center/cover;left:0;width:100%;height:400px;position:absolute;opacity:0.4}header .landing-content{z-index:1;color:white}#section-a{height:300px;text-align:center;background-color:#333}