*{box-sizing:border-box}body{font:16px system-ui;margin:0;color:#15294c;background:#edf4fc}header,footer{padding:20px;background:#102b60;color:white}main{max-width:900px;margin:30px auto;padding:16px}section{background:white;border-radius:18px;padding:32px;box-shadow:0 5px 25px #1232}button{background:#126caa;color:white;border:0;border-radius:10px;padding:12px 18px;cursor:pointer}@media(max-width:500px){section{padding:18px}h1{font-size:1.5rem}}