body {
  padding-left: 125px;
}

menu {
  position: fixed;
  width: 125px;
  height: 100%;
  background-color: #eeeeee;
  border: none;
  top: 0;
  left: 0;
  list-style: none;
  margin: 0;
  padding: 10px 0 0 0;
  overflow: auto;
}

menu a {
  display: block;
  width: 100px;
  height: 40px;
  background-size: 8000px 40px;
  text-indent: -9999px;
  background-size: 100px 40px;
  border: none;
  margin: 32px 13px;
}

/* preload images */
body::after {
  position: absolute;
  width: 0;
  height: 0;
  overflow: hidden;
  content: url("gif/home.gif") url("gif/home.gif") url("gif/palp.gif") url("gif/k3.gif") url("gif/cy.gif") url("gif/ff.gif") url("gif/lg.gif") url("gif/csws.gif") url("gif/rgc.gif") url("gif/Bhome.gif") url("gif/Bhome.gif") url("gif/Bpalp.gif") url("gif/Bk3.gif") url("gif/Bcy.gif") url("gif/Bff.gif") url("gif/Blg.gif") url("gif/Bcsws.gif") url("gif/Brgc.gif");
}

menu .home a {
  background-image: url("gif/Ghome.gif");
}

menu .home a:hover {
  background-image: url("gif/home.gif");
}

menu .home.active a {
  background-image: url("gif/Bhome.gif");
}

menu .palp a {
  background-image: url("gif/Gpalp.gif");
}

menu .palp a:hover {
  background-image: url("gif/palp.gif");
}

menu .palp.active a {
  background-image: url("gif/Bpalp.gif");
}

menu .k3 a {
  background-image: url("gif/Gk3.gif");
}

menu .k3 a:hover {
  background-image: url("gif/k3.gif");
}

menu .k3.active a {
  background-image: url("gif/Bk3.gif");
}

menu .cy a {
  background-image: url("gif/Gcy.gif");
}

menu .cy a:hover {
  background-image: url("gif/cy.gif");
}

menu .cy.active a {
  background-image: url("gif/Bcy.gif");
}

menu .ff a {
  background-image: url("gif/Gff.gif");
}

menu .ff a:hover {
  background-image: url("gif/ff.gif");
}

menu .ff.active a {
  background-image: url("gif/Bff.gif");
}

menu .lg a {
  background-image: url("gif/Glg.gif");
}

menu .lg a:hover {
  background-image: url("gif/lg.gif");
}

menu .lg.active a {
  background-image: url("gif/Blg.gif");
}

menu .csws a {
  background-image: url("gif/Gcsws.gif");
}

menu .csws a:hover {
  background-image: url("gif/csws.gif");
}

menu .csws.active a {
  background-image: url("gif/Bcsws.gif");
}

menu .rgc a {
  background-image: url("gif/Grgc.gif");
}

menu .rgc a:hover {
  background-image: url("gif/rgc.gif");
}

menu .rgc.active a {
  background-image: url("gif/Brgc.gif");
}