*{-webkit-box-sizing:border-box;box-sizing:border-box;font-family:Menlo, Consolas, monospace;font-size:13px}html,body{width:100%;height:100%;margin:0;padding:0}.flex-center{display:-webkit-box;display:-ms-flexbox;display:flex;place-content:center;place-items:center}#main{padding:10px}form input{border:2px solid black;outline:none;padding:2px 6px}input[type='submit']{cursor:pointer}