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

html, body {
  width: 100vw;
  height: 100vh;
  overflow: hidden;
  margin: 0;
  background: black;
  display: flex;
  justify-content: center;
  align-items: center;
  font-family: sans-serif;
  color: white;
}

#startScreen {
  display: flex;
  flex-direction: column;
  align-items: center;
}

#startBtn {
  padding: 1rem 2rem;
  font-size: 1.2rem;
  background: #222;
  color: white;
  border: 2px solid white;
  border-radius: 8px;
  cursor: pointer;
  transition: 0.2s;
}

#startBtn:hover {
  background: white;
  color: black;
}

#loopGif {
  width: 100vw;
  height: 100vh;
  object-fit: contain;
}

#mainContent {
  opacity: 0;
  transition: opacity 1s ease;
  flex-direction: column;
  align-items: center;
  justify-content: center;
}

#mainContent.visible {
  opacity: 1;
}