body {
  text-align: center;
  margin: 0;
  padding: 0;
  color: #ffffff;
  font-family: sans-serif;
}

h1, h3, p, pre {
  margin: 0;
  padding: 0;
}

a {
  color: #009900;
}
.footer {
  position: absolute;
  bottom: 0;
  width: 100%;
}

body {
  background: linear-gradient(to bottom, #880000, #aa0000);
}

pre {
  background-color: #990000;
  color: #009900;
  font-family: monospace;
  padding: 1em;
  white-space: pre-wrap;
}

h1, h3 {
  color: #ffffff;
}

.clickable {
  background-color: #009900;
  border: none;
  color: #ffffff;
  padding: 0.5em 1em;
  margin: 0.5em;
  cursor: pointer;
}

.snow {
  position: fixed;
  width: 100%;
  height: 100%;
  pointer-events: none;
  z-index: 100;
}

.snow__flake {
  position: absolute;
  top: -50px;
  left: -50px;
  right: -50px;
  bottom: -50px;
  width: 10px;
  height: 10px;
  background: #fff;
  border-radius: 50%;
  animation: snowAnimation 3s linear infinite;
}

.snow__flake:nth-child(0) {
  animation-delay: 0s;
}

.snow__flake:nth-child(1) {
  animation-delay: 0.2s;
}

.snow__flake:nth-child(2) {
  animation-delay: 0.4s;
}

.snow__flake:nth-child(3) {
  animation-delay: 0.6s;
}

.snow__flake:nth-child(4) {
  animation-delay: 0.8s;
}

.snow__flake:nth-child(5) {
  animation-delay: 1s;
}

.snow__flake:nth-child(6) {
  animation-delay: 1.2s;
}

.snow__flake:nth-child(7) {
  animation-delay: 1.4s;
}

.snow__flake:nth-child(8) {
  animation-delay: 1.6s;
}

.snow__flake:nth-child(9) {
  animation-delay: 1.8s;
}

.snow__flake:nth-child(10) {
  animation-delay: 2s;
}

@keyframes snowAnimation {
  0% {
    transform: translateY(0) rotate(0deg);
    opacity: 1;
  }
  100% {
  transform: translateY(1000px) rotate(360deg);
  opacity: 0;
  }
}