html {
    height: 100%;
    margin: 0;
    font-family: Verdana, Geneva, Tahoma, sans-serif;
    background: linear-gradient(180deg, yellow, black 100%);
    color: #333;
  }
  
  h1 {
    color: #2c3e50;
    margin-bottom: 0.5em;
  }
  
  p {
    margin-bottom: 1em;
  }
  
  #app {
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    height: 100%;
    text-align: center;
    
  }
  
  #keyInput,
  #output {
    max-width: 600px;
    width: 90%;
    margin: 10px auto;
    padding: 15px;
    border: none;
    background-color: #ecf0f1;
    border-radius: 4px;
    box-shadow: 0 4px 6px rgba(0, 0, 0, 0.1);
    font-size: 1.1em;
    color: #333;
  }
  
  #keyInput {
    display: none;
  }
  
  #output p {
    font-size: 1.2em;
    margin: 25px 0;
  
  }
  
  #output span {
    display: inline-block;
    min-width: 50px;
    padding: 2px 5px;
    font-weight: bold;
    color: #3d27ae;
    border-radius: 3px;
    background-color: #eafaf1;
  }
  
  @media (max-width: 768px) {
    #keyInput {
      display: block;
      text-align: center;
    }
  }