html,body{height:100%;margin:0;font-family:Arial,sans-serif}body{background:url(images/fondo.jpg) center/cover fixed;display:flex}.overlay{flex:1;background:rgba(0,0,0,.55);display:flex;align-items:center;justify-content:center;padding:20px}.card{max-width:760px;color:#fff;background:rgba(255,255,255,.12);backdrop-filter:blur(10px);padding:40px;border-radius:20px;text-align:center;box-shadow:0 8px 30px rgba(0,0,0,.4)}#cd{font-size:2rem;font-weight:bold;margin:30px 0}