*{margin:0;padding:0;box-sizing:border-box;font-family:Arial,Helvetica,sans-serif}body{background:#f7f7f7;color:#222}.center{height:100vh;display:flex;flex-direction:column;align-items:center;justify-content:center;text-align:center}.button{background:#111;color:#fff;padding:12px 24px;border:none;border-radius:6px;cursor:pointer;font-size:16px}.button:hover{opacity:.9}.card{border:1px solid #ddd;padding:16px;border-radius:8px;cursor:pointer;width:220px}.card:hover{background:#eee}