body {font-family: Arial; margin:0; background:#0b0f14; color:white;}
.hero {height:100vh; background:url('https://images.unsplash.com/photo-1586773860418-d37222d8fce3') 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 {padding:10px 20px; background:green; color:white; text-decoration:none;}
.card {margin:20px;}