*{box-sizing:border-box;margin:0;padding:0}body{color:#222;background:#f5f7fa;padding:40px;font-family:system-ui,-apple-system,Segoe UI,Roboto,sans-serif}header{margin-bottom:80px}hr{margin-top:150px}#btn{color:#fff;cursor:pointer;background-color:#4361ee;border:none;border-radius:7px;padding:12px 24px;font-size:1rem;font-weight:600}#btn:hover{transform:scale(1.2)}#output{margin-top:40px}