body {
  background-color: lightblue;
}

h1 {
  color: red;
}

// * { margin:0; padding:0; } /* to remove the top and left whitespace */

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

.button {
  border: 2px solid #73AD21;
  color: blue;
  padding: 15px 32px;
  text-align: center;
  text-decoration: none;
  display: inline-block;
  font-size: 16px;
  margin: 4px 2px;
  border-radius: 10%;
  box-shadow: 10px 10px 5px grey;
  transition-duration: 0.4s;
  cursor: pointer;
}
.button:hover {
  background-color: #4CAF50;
  color: white;
}

canvas{
    border: 2px solid #00FFFF;
    margin: 0;          // remove top and left white space
    padding: 0;         // remove top and left white space
    display: block;     // remove the scroll bars (doesn't work)
}