body {
  display: flex;
  justify-content: center;
  align-items: center;
  height: 100vh;
  margin: 0;
  background-image: url(https://wallpapercave.com/wp/wp8984736.jpg);
  background-size: cover;
  background-repeat: no-repeat;
  background-attachment: fixed;
  background-position: center;
}

:root {
  --color: #fff;
  --background-color: #14151a;
  --exitbutton-color: #b75a5a;
  --canvas-color: #efece3;
  --hover-color: #4e4f52;
}

#game-container {
  position: relative;
  display: flex;
  flex-direction: column;
  align-items: center;
}

canvas {
  border-radius: 7px;
  border: 3px solid var(--canvas-color);
  background: var(--canvas-color);
  max-width: 100%;
  max-height: 100%;
  width: auto;
  height: auto;
}

#playButton,
#restartButton,
#exitButton {
  width: 90px;
  height: 40px;
  background-color: var(--background-color);
  border: 2px solid var(--background-color);
  text-decoration: none;
  border-radius: 10px;
  font-size: 16px;
  font-weight: 600;
  letter-spacing: 1px;
  color: var(--color);
  transition: 0.7s ease;
  position: absolute;
  left: 50%;
  transform: translateX(-50%);
}

#playButton {
  bottom: 20%;
}

#restartButton {
  bottom: 5%;
  display: none;
}

#exitButton {
  top: 10px;
  right: 10px;
  left: auto;
  transform: none;
  width: 40px;
  background-color: var(--exitbutton-color);
  border: 1px solid var(--exitbutton-color);
  height: 30px;
  font-size: 14px;
  display: none;
}

#playButton:hover {
  background-color: var(--hover-color);
  border: 2px solid var(--hover-color);
}