#offcanvas {
  display: none;
  position: fixed;
  top: 0;
  height: 100vh;
  background: #888;
  box-shadow: 0 0 15px #000 inset;
}

#offcanvas a {
  color: #FFF;
  display: block;
  border-bottom: 1px solid rgba(255,255,255,0.5);
  padding: 15px;
}