body {
    font-family: "Arial", sans-serif;
    color: #FFFFFF;
    background-color: #000000;
  }

  input {
    width: 300px;
    margin-bottom: 10px;
  }

  button {
    background-color: blue;
    color: white;
    padding: 10px;
    cursor: pointer;
  }

  .disabled {
    opacity: 0.5;
    cursor: not-allowed;
  }

  #link:invalid+p {
    display: block;
  }