.bubble-bg {
  font-family: system-ui, "Segoe UI", Roboto, Helvetica, Arial, sans-serif, "Apple Color Emoji", "Segoe UI Emoji", "Segoe UI Symbol";
  width: 100%;
  height: 400px;
  background: linear-gradient(120deg, #84fab0 0%, #8fd3f4 100%);
  position: relative;
  overflow: hidden;
  display: flex;
  align-items: center;
  justify-content: center;
  border-radius: 12px;
}
.center-content {
  z-index: 2;
  color: #fff;
  text-shadow: 0 2px 10px rgba(0,0,0,0.1);
  font-size: 2rem;
}
.bubble {
  position: absolute;
  bottom: -100px;
  background: rgba(255, 255, 255, 0.3);
  border-radius: 50%;
  animation: rise 10s infinite linear;
}
.bubble:nth-child(1) {
  width: 80px;
  height: 80px;
  left: 10%;
  animation-duration: 8s;
}
.bubble:nth-child(2) {
  width: 40px;
  height: 40px;
  left: 20%;
  animation-duration: 12s;
  animation-delay: 2s;
}
.bubble:nth-child(3) {
  width: 120px;
  height: 120px;
  left: 70%;
  animation-duration: 15s;
  animation-delay: 1s;
}
.bubble:nth-child(4) {
  width: 60px;
  height: 60px;
  left: 85%;
  animation-duration: 9s;
  animation-delay: 4s;
}
@keyframes rise {
  0% {
    bottom: -100px;
    transform: translateX(0);
  }
  50% {
    transform: translateX(50px);
  }
  100% {
    bottom: 108%;
    transform: translateX(-50px);
  }
}