* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

html,
body {
  height: 100%;
  overflow: hidden;
  width: 100%;
  background-color: #000;
  font-family: "Arial", sans-serif;
}

#fireworks {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  z-index: 0;
}

.center-container {
  z-index: 1;
  position: absolute;
  height: 100%;
  width: 100%;
  display: flex;
  flex-direction: column;
  align-items: center;
  padding: 1rem;
}

#image-sequence {
  z-index: 2;
}

.sequence-img {
  position: absolute;
  top: 10%;
  left: 15%;
  opacity: 0;
  max-width: 70%;
  animation-fill-mode: forwards;
}

@keyframes fadeZoomIn {
  0% {
    opacity: 0;
    transform: scale(0.5);
  }
  100% {
    opacity: 1;
    transform: scale(1);
  }
}

@keyframes slideInLeft {
  0% {
    opacity: 0;
    transform: translateX(-100%);
  }
  100% {
    opacity: 1;
    transform: translateX(0);
  }
}

@keyframes rotateIn {
  0% {
    opacity: 0;
    transform: rotate(-180deg) scale(0.5);
  }
  100% {
    opacity: 1;
    transform: rotate(0deg) scale(1);
  }
}
#birthday-text {
  color: white;
  font-size: 3rem;
  font-family: Quicksand, sans-serif;
  text-shadow: #bb2121 0px 10px 10px;
  margin: 20px auto;
  opacity: 0;
  animation: fadeIn 2s ease forwards;
  animation-delay: 5s;
  z-index: 3;
}

h2 {
  color: rgb(255, 0, 0);
  font-size: 2.4rem;
  font-family: Quicksand, sans-serif;
  text-shadow: #bb2121 0px 10px 10px;
  margin: 10rem auto;
  opacity: 0;
  animation: fadeIn 2s ease forwards;
  animation-delay: 6s;
  z-index: 3;
}
@keyframes fadeIn {
  to {
    opacity: 1;
  }
}
@keyframes fadeOut {
  to {
    opacity: 0;
  }
}

#stop-music {
  position: absolute;
  bottom: 20px;
  right: 20px;
  padding: 10px 20px;
  background-color: #ff0000;
  color: white;
  border: none;
  border-radius: 5px;
  cursor: pointer;
  z-index: 4;
}
#stop-music:hover {
  background-color: #8f1414;
}
#stop-music:active {
  background-color: #990000;
}
#stop-music:focus {
  outline: none;
}
#stop-music:focus-visible {
  outline: 2px solid #ffffff;
  outline-offset: 2px;
}
#stop-music:disabled {
  background-color: #cccccc;
  cursor: not-allowed;
}

#start-music {
  position: absolute;
  bottom: 20px;
  right: 100px;
  padding: 10px 20px;
  background-color: #3998e1;
  color: white;
  border: none;
  border-radius: 5px;
  cursor: pointer;
  z-index: 4;
}
#start-music:hover {
  background-color: #32269f;
}
#start-music:active {
  background-color: #009900;
}
#start-music:focus {
  outline: none;
}
#start-music:focus-visible {
  outline: 2px solid #ffffff;
  outline-offset: 2px;
}
#start-music:disabled {
  background-color: #cccccc;
  cursor: not-allowed;
}