body {
  background-image: url('https://i.pinimg.com/736x/0e/60/a6/0e60a6eb9c44189819a228915ff5a26b.jpg');
  background-size: cover;
  background-repeat: no-repeat;
  background-attachment: fixed;
  margin: 0;
  padding: 0;
}
.hidden {display: none;}
.card {text-align: center; font-family: Arial, sans-serif; margin-top: 50px; padding: 0 20px;}
.envelope {width: 150px; height: 100px; background: pink; margin: 0 auto; cursor: pointer; display: flex; align-items: center; justify-content: center; font-size: 50px; border-radius: 10px; box-shadow: 0 5px 15px rgba(0,0,0,0.3);}
.message {margin-top: 20px; background: rgba(255,255,255,0.85); padding: 20px; border-radius: 10px; display: inline-block;}
.greeting-text {max-width: 600px; margin: 0 auto 20px auto; font-size: 16px; line-height: 1.5; text-align: justify;}
.slideshow-container {max-width: 400px; position: relative; margin: auto;}
.mySlides {display: none;}
.fade {animation: fade 3s;}
@keyframes fade {from {opacity: .4} to {opacity: 1}}