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

body{
  width: 100vw;
  height:100vh;
  display:flex;
  justify-content: center;
  align-items: center;
}
canvas {
width: 800px;
height: 500px;
border: 7px solid orange;
  background-color: lightblue;
 } 

.startButton {
  position: absolute;
  bottom: 20%;
  left: 50%;
   transform: translate(-50%, 0);
  background: orange;
  color: white;
  padding: 50px 200px;
  border-radius: 5px;
  z-index: 100;
  cursor: pointer;
  border: none;
  outline: none;
  font-size: 50px;
  
}