/* panel layout mechanics */
.panel-wrap {
  position: fixed;
  top: 0;
  bottom: 0;
  right: 0;
  width: 30em;
  transform: translateX(100%);
  transition: .3s ease-out;
}
.panel {
  position: absolute;
  top: 0;
  bottom: 0;
  left: 0;
  right: 0;
  background: #333;
  color: #eee;
  overflow: auto;
  padding: 1em;
}

/* simulate panel state control --
this can also be triggered by a 
class name added to the body tag. 
Just using a checkbox sibling here
for simplicity
*/ 
[type="checkbox"]:checked ~ .panel-wrap {
  transform: translateX(0%);
}


/* demo display */
*,*:before, *:after {box-sizing: border-box;}

body {
  font-family: sans-serif;
  font-size: 18px;
}
h3 {
  margin: 0;
}
p {
  line-height: 1.4;
  margin: 2em 0 0 0;
}
[type="checkbox"] {
  font-size: 1em;
}