.win9xcore{
  font-family: sans-serif;
width: 20%;
contain: size;
}
.win9xtop{
  border: 5px;
  background-color: blue;
  border-style: outset;
  border-bottom-style: none;
  border-color: navy;
}
body{
  background-color: black;
  background-image: url("https://edsschoolwebstuff.neocities.org/basicmaze/globalfiles/greensquare.png");
  animation: bgscroll 5s linear infinite;
  image-rendering: crisp-edges;
}
.win9xbody{
  padding: 10%;
  background-color: lightgrey;
  border: 5px;
  border-style: outset;
  border-top-style: none;
  margin: auto;
  text-align: center;
}
@keyframes bgscroll {
 from {
   background-position-x: 0px;
   background-position-y: 0px;
 }
 to {
   background-position-x: 64px;
   background-position-y: 64px;
 }
}
.viewport {
  margin: auto;
  background-color: black;
  border-width: 1vh;
  border-color: white ;
  border-style: ridge;
  width: 90vh;
  height: 90vh;
  margin-top: 3vh;
  margin-bottom: 3vh;
}