/* ------------------------------------------
 * IT书包
 * 网址：www.itshubao.com
 * 整理：yinq<3331653644@qq.com> 
 -------------------------------------------- */
h1, h2, h3 {
  text-align: center;
}

h1 {
  font-size: 3em;
}

h2 {
  font-size: 2em;
  font-weight: 100;
}

body {
  height: 100%;
  height: 100vh;
  overflow: hidden;
  font-family: 'Microsoft YaHei', sans-serif;
  color: #666;
}

body * {
  box-sizing: border-box;
}

menu .fa {
  margin-right: 10px;
  margin-left: -10px;
}

header .icon {
  -webkit-transition: 0.3s;
  transition: 0.3s;
  margin-left: 1em;
}

header {
  width: 100%;
  height: 50px;
  padding: 1em 0;
  position: relative;
  font-weight: 800;
  text-align: center;
  color: #fff;
  background: #0091EA;
  box-shadow: 2px 2px 2px #01579B;
  -webkit-transition: 0.5s;
  transition: 0.5s;
}

.menu {
  margin: 0;
  padding: 0;
  text-align: center;
  background: #00B0FF;
  overflow: hidden;
  -webkit-transition: 0.4s;
  transition: 0.4s;
  -webkit-transition-delay: 0.5s;
  transition-delay: 0.5s;
  max-height: 0;
}

menuitem {
  display: block;
  padding: 1em;
  margin-left: -130%;
  font-weight: 300;
  -webkit-transition: 0.4s;
  transition: 0.4s;
  cursor: pointer;
  opacity: 0;
}
menuitem:hover {
  background: #33c0ff;
}

footer {
  bottom: 0;
  position: absolute;
  width: 40%;
  left: 30%;
  -webkit-transition: 0.2s;
  transition: 0.2s;
  color: #fff;
}
footer:hover menu {
  max-height: 400px;
}
footer:hover menuitem {
  margin-left: 0;
  opacity: 1;
}
footer:hover header .icon {
  -webkit-transform: rotate(90deg);
  transform: rotate(90deg);
  /*padding-left:0;*/
}
footer:hover header {
  height: 70px;
}
footer:hover .instructions {
  width: 100%;
  opacity: 0.7;
}

.instructions {
  width: 0;
  position: absolute;
  opacity: 0;
  overflow: hidden;
  padding: 0.6em;
  font-weight: 100;
  transition: 0.4s;
  -webkit-transition: 0.4s;
  -moz-transition: 0.4s;
}