body {background: #dfe; padding: 0 1ex:}
h1 {border: 2px green solid; border-radius 2em; background: #ded;
  padding: 0.1ex 1ex;
}
h1.fixed {
  position: fixed; top: 0; z-index: 2; box-shadow: #66a 5px 5px 5px;
  width: 90%; white-space: pre; overflow: auto;
}
h2 {border: green solid; border-width: 0 0 2px 1em; padding-left: 1ex;}
*.err {color: red;}
h1.fixed + * {margin-top: 6em;}
h3 {background: #efe;}
pre {background: #ffe;}
input[type="radio"] {xfont-size: x-large;
  margin-left: 1em;
  -moz-transform-origin: right bottom;
  x-moz-transform: scale(1.5, 1.5);
  -webkit-transform-origin: right bottom;
  x-webkit-transform: scale(1.5, 1.5);
}
h3 + input[type="radio"] {margin-left: 3em;}
input:checked + label {background: #ffa;}
  span.chunk {white-space: pre; margin-left: 1em;}
div.footer {
  border-top: double 5px green;
}
span.done {}
span.notyet {color: red;}