body {
  width: 100vw;
  height: 100vh;
  margin: 0;
  display: flex;
  flex-direction: column;
  align-items: center;
}

iframe {
  width: 100%;
  height: 100%;
  border: 0;
  padding: 0;
  margin: 0;
}

#button-container {
  display: flex;
  justify-content: center;
}

#animation-target {
  width: 30px;
  height: 15px;
  background-color: red;
  border-radius: 25%;
}

button {
  padding: 10px;
  margin: 5px;
}