body{margin:0;font-family:Arial;background:#0a0f14;color:#fff;}
.hero{height:100vh;background:url('https://images.unsplash.com/photo-1501004318641-b39e6451bec6') center/cover;}
.overlay{background:rgba(0,0,0,0.6);height:100%;display:flex;flex-direction:column;justify-content:center;align-items:center;}
h1{font-size:48px;}
.section{padding:60px;text-align:center;}
.section.dark{background:#111;}
.btn{background:#00aa55;padding:12px 24px;color:#fff;text-decoration:none;}
.card{margin:20px;}