body {
  background-color: pink;
  display: flex;
  justify-content: center;
  align-items: center;
  height: 100vh;
  font-family: 'Segoe UI', sans-serif;
  margin: 0;
  overflow: hidden;
}

/* AMPOP UTAMA */
.amplop {
  position: relative;
  width: 300px;
  height: 200px;
  background-color: #87CEFA;
  border: 2px solid #ff8c;
  border-radius: 10px;
  overflow: hidden;
  cursor: pointer;
  box-shadow: 0 5px 15px rgba(0,0,0,0.2);
  transition: all 0.6s ease;
}

/* TUTUP AMPOP */
.tutup {
  position: absolute;
  top: 0;
  left: 0;
  width: 300px;
  height: 100px;
  background-color: #4682B4;
  transform-origin: top;
  transition: transform 1.2s ease; /* Lebih lambat */
  clip-path: polygon(0 0, 100% 0, 50% 100%);
}

/* ISI SURAT */
.isi {
  opacity: 0;
  padding: 20px;
  background-color: #ff8c;
  height: 100%;
  box-sizing: border-box;
  transition: opacity 0.5s ease;
  text-align: left;
  font-size: 14px;
  color: #333;
  z-index: 2;
  position: relative;
}

/* BALON DI BELAKANG */
.balon-container {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  pointer-events: none;
  overflow: hidden;
  z-index: 0;
}

.balon {
  position: absolute;
  bottom: 0;
  width: 30px;
  height: 40px;
  background-color: red;
  border-radius: 50%;
  animation: naik 5s linear infinite;
  opacity: 0.8;
}

@keyframes naik {
  0% {
    transform: translateY(0) scale(1);
  }
  100% {
    transform: translateY(-100vh) scale(1.2);
  }
}

/* ANIMASI GETAR */
@keyframes shake {
  0% { transform: rotate(0deg); }
  25% { transform: rotate(2deg); }
  50% { transform: rotate(-2deg); }
  75% { transform: rotate(2deg); }
  100% { transform: rotate(0deg); }
}

.amplop.shake {
  animation: shake 0.5s ease;
}