/* ================= BUBBLES ================= */
.bubble {
  position: absolute;
  bottom: -120px;
  width: 40px;
  height: 40px;
  background: rgba(255, 255, 255, 0.18);
  border-radius: 50%;
  filter: blur(1px);
  animation: rise 18s infinite ease-in;
}

.bubble:nth-child(1) {
  left: 10%;
  width: 18px;
  height: 18px;
  animation-duration: 12s;
}
.bubble:nth-child(2) {
  left: 22%;
  animation-duration: 16s;
}
.bubble:nth-child(3) {
  left: 35%;
  width: 60px;
  height: 60px;
  animation-duration: 22s;
}
.bubble:nth-child(4) {
  left: 50%;
  animation-duration: 18s;
}
.bubble:nth-child(5) {
  left: 65%;
  width: 30px;
  height: 30px;
  animation-duration: 14s;
}
.bubble:nth-child(6) {
  left: 80%;
  animation-duration: 20s;
}
.bubble:nth-child(7) {
  left: 92%;
  width: 15px;
  height: 15px;
  animation-duration: 17s;
}

@keyframes rise {
  0% {
    transform: translateY(0);
    opacity: 0;
  }
  10% {
    opacity: 1;
  }
  100% {
    transform: translateY(-130vh);
    opacity: 0;
  }
}

/* ================= SCIENCE SYMBOLS ================= */
.science-symbol {
  position: absolute;
  bottom: -50px;
  font-size: 22px;
  color: rgba(255, 255, 255, 0.35);
  animation: floatSymbol 20s infinite linear;
}

.science-symbol:nth-child(8) {
  left: 15%;
  animation-duration: 22s;
}
.science-symbol:nth-child(9) {
  left: 30%;
  animation-duration: 26s;
}
.science-symbol:nth-child(10) {
  left: 45%;
  animation-duration: 24s;
}
.science-symbol:nth-child(11) {
  left: 60%;
  animation-duration: 28s;
}
.science-symbol:nth-child(12) {
  left: 75%;
  animation-duration: 30s;
}

@keyframes floatSymbol {
  from {
    transform: translateY(0) rotate(0deg);
    opacity: 0;
  }
  10% {
    opacity: 0.6;
  }
  to {
    transform: translateY(-120vh) rotate(360deg);
    opacity: 0;
  }
}