body {
  background:white url("side_line.png") no-repeat fixed;
  color:black;
}
/* Extra definitions only need for Piano section */
/* Music-related */
img[src="/tutorials/Piano/flat.png"] { /* Flat symbol */
  width:6px;
  height:14px;
}
img[src="/tutorials/Piano/natrual.png"] { /* Natrual symbol */
  width:6px;
  height:13px;
}
img[src="/tutorials/Piano/sharp.png"] { /* Sharp symbol */
  width:7px;
  height:15px;
}