#dosbox {
  width: 640px;
  height: 400px;
}

.dosbox-container {
  width: 640px;
  height: 400px;
}

.dosbox-container > .dosbox-overlay {
  background-size: 640px 400px;
}

body {
  font-family: 'Perfect DOS VGA 437', sans-serif;
  background: #000;
  color: #ddd;
}

@font-face {
  font-family: 'Perfect DOS VGA 437', sans-serif;
  src: url('https://fonts.cdnfonts.com/css/perfect-dos-vga-437');
}