kbd.css

kbd {
  font-family: Consolas, "Lucida Console", monospace;
  display: inline-block;
  border-radius: 3px;
  padding: 0px 4px;
  box-shadow: 1px 1px 1px #777;
  margin: 2px;
  font-size: small;
  vertical-align: text-bottom;
  background: #eee;
  font-weight: 500;
  color: #555;
  cursor: pointer;
  font-variant: small-caps;
  font-weight: 600;

  /* This two work */
  /* letter-spacing: 0.5px; */
  letter-spacing: 1px;


  /* Prevent selection */
  -webkit-touch-callout: none;
  -webkit-user-select: none;
  -khtml-user-select: none;
  -moz-user-select: none;
  -ms-user-select: none;
  user-select: none;
}

kbd:hover, kbd:hover * {
  color: black;
  /* box-shadow: 1px 1px 1px #333; */
}
kbd:active, kbd:active * {
  color: black;
  box-shadow: 1px 1px 0px #ddd inset;
}

kbd kbd {
  padding: 0px;
  margin: 0 1px;
  box-shadow: 0px 0px 0px black;
  vertical-align: baseline;
  background: none;
}

kbd kbd:hover {
  box-shadow: 0px 0px 0px black;
}

kbd:active kbd {
  box-shadow: 0px 0px 0px black;
  background: none;
}

/* Deep blue */
kbd.deep-blue, .deep-blue kbd {
  background: steelblue;
  color: #eee;
}

kbd.deep-blue:hover, kbd.deep-blue:hover *, .deep-blue kbd:hover {
  color: white;
}

/* Dark apple */
kbd.dark-apple, .dark-apple kbd {
  background: black;
  color: #ddd;
}

kbd.dark-apple:hover, kbd.dark-apple:hover *, .dark-apple kbd:hover {
  color: white;
}

/* Type writer */
kbd.type-writer, .type-writer kbd {
  border-radius: 10px;
  background: #333;
  color: white;
}