html, body {
  width: 100%;
  height: 99%;
  margin: 0;
  padding: 0;
}

#gameContainer {
  width: 95%;
  height: 95%;
  margin: 1% auto;
  position: relative;
}

#gameCanvas {
  width: 100%;
  height: 100%;
  background-image: url(background0.jpg);
  background-size: cover;
  background-repeat: repeat-horizontally;
}

button {
  width: 200px;
  height: 50px;
  position: absolute;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
}

#startButton {
  display: block;
}

#playAgainButton, #nextButton {
  display: none;
}

#messageBox {
  width: 40%;
  text-align: center;
  position: absolute;
  top: 20%;
  left: 30%;
  padding-top: 20px;
  padding-bottom: 20px;
  background-color: lightgray;
  border-radius: 10px;
  box-shadow: 0 0 10px rgba(0,0,0,0.5);
  font-size: 24px;
  font-weight: bold;
}

#scoreContainer {
  position: absolute;
  top: 10px;
  right: 10px;
  padding: 10px;
  background-color: lightgray;
  border-radius: 10px;
  box-shadow: 0 0 10px rgba(0,0,0,0.5);
  font-size: 18px;
}