body 
{ 
  font: 14px Arial, sans-serif;
  color: white; 
  background: black; 
}


h1 
{ 
  font: bold 24px Arial;
  text-align: center; 
}


h2 
{ 
  font: bold 18px Arial;
  text-align: center; 
}

h3
{
  font: bold 16px Arial;
}


canvas 
{ 
  border: 1px solid gray; 
  margin-left: auto; 
  margin-right: auto; 
  display: block; 
}


.center
{ 
  text-align: center;
}


iframe
{
  width: 640px;
  margin-left: auto;
  margin-right: auto;
  display: block;
  border: 0px;
}

.assignment
{
  width: 640px;
  margin-left: auto;
  margin-right: auto;
}