style.css

@import url('https://fonts.googleapis.com/css2?family=Poppins:wght@300;600;800&display=swap');

* {
    margin: 0px;
    padding: 0px;
    font-family: 'Poppins', sans-serif;
}

#container {
    border-radius: 20px;
    padding: 50px;
    margin: 50px auto;
    transition: all 0.5s;
  }

#container:hover {
    border: 2px solid rgba(255, 255, 255, 0.35);
    box-shadow: 0px 0px 60px -6px rgba(255, 255, 255, 0.35);
    -webkit-box-shadow: 0px 0px 60px -6px rgba(255, 255, 255, 0.35);
    -moz-box-shadow: 0px 0px 60px -6px rgba(255, 255, 255, 0.35);
  }

#enter-message{
  color: #ffff;
}

#enter-key{
  color: #ffff;
} 

#result-encrypt{
  color: #ffff;
}

#encrypted-message{
  color: #ffff;
}

#value-key{
  color: #ffff;
}

#result-decrypt{
  color: #ffff;
}