/* ------------------------------------------
 * IT书包
 * 网址：www.itshubao.com
 * 整理：yinq<3331653644@qq.com> 
 -------------------------------------------- */
*, *:before, *:after {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

body {
  text-align: center;
  font-family: 'Microsoft YaHei', serif;
  background-color: #fafafa;
}

article {
  padding: 8rem 1rem;
  border-bottom: 1px solid #ebeaea;
}
article p {
  display: block;
  max-width: 50rem;
  margin: 0 auto;
  color: grey;
  text-align: left;
  font-size: 1.2rem;
  line-height: 1.7rem;
}
article p::-moz-selection {
  color: black;
  background-color: #fae900;
}
article p::selection {
  color: black;
  background-color: #fae900;
}
article p a {
  color: #0079c2;
  text-decoration: none;
  -webkit-transition: all .15s;
  transition: all .15s;
}
article p a:hover {
  background-color: #fae900;
  color: black;
}
article p a::-moz-selection {
  color: black;
  background-color: #fae900;
}
article p a::selection {
  color: black;
  background-color: #fae900;
}

.btn-fold-1 {
  position: relative;
  display: inline-block;
  width: 28rem;
  z-index: 1;
  font-family: 'Varela Round', sans-serif;
  text-decoration: none;
  font-size: 2.5rem;
  color: black;
  text-transform: uppercase;
  letter-spacing: 0.1rem;
  -webkit-transform-style: preserve-3d;
          transform-style: preserve-3d;
  -webkit-perspective: 800px;
          perspective: 800px;
  -webkit-perspective-origin: 50% 200%;
          perspective-origin: 50% 200%;
  -webkit-transform: translateX(-25%) translateZ(0);
          transform: translateX(-25%) translateZ(0);
  -webkit-transition: -webkit-transform 0.8s;
  transition: -webkit-transform 0.8s;
  transition: transform 0.8s;
  transition: transform 0.8s, -webkit-transform 0.8s;
}
.btn-fold-1 span {
  position: relative;
  display: block;
  width: 50%;
  float: left;
  padding-top: 1rem;
  padding-bottom: .7rem;
  text-align: right;
}
.btn-fold-1 span:last-child {
  z-index: 2;
  padding-right: 1rem;
  padding-left: .6rem;
  text-align: left;
  background-color: #fae900;
}
.btn-fold-1 span:first-child {
  z-index: 3;
  padding-right: .6rem;
  padding-left: 1rem;
  pointer-events: none;
  background-color: #fae900;
  -webkit-backface-visibility: visible;
          backface-visibility: visible;
  -webkit-transform-origin: 100% 50%;
          transform-origin: 100% 50%;
  -webkit-transform: rotateY(179.9deg);
          transform: rotateY(179.9deg);
  -webkit-transition: -webkit-transform 0.4s ease-in-out;
  transition: -webkit-transform 0.4s ease-in-out;
  transition: transform 0.4s ease-in-out;
  transition: transform 0.4s ease-in-out, -webkit-transform 0.4s ease-in-out;
}
.btn-fold-1 span:first-child:before {
  content: 'Donate';
  position: absolute;
  top: 0;
  right: 0;
  bottom: 0;
  left: 0;
  padding-top: 1rem;
  z-index: 4;
  color: white;
  text-align: center;
  background-color: #0079c2;
  -webkit-transform: rotateY(180deg);
          transform: rotateY(180deg);
  -webkit-transition: color 0s 0.2s, background-color 0s 0.2s;
  transition: color 0s 0.2s, background-color 0s 0.2s;
  -webkit-transition-timing-function: ease-in-out;
          transition-timing-function: ease-in-out;
}
.btn-fold-1:hover {
  -webkit-transform: translateX(0) translateZ(0);
          transform: translateX(0) translateZ(0);
}
.btn-fold-1:hover > span:first-child {
  -webkit-transform: rotateY(0);
          transform: rotateY(0);
}
.btn-fold-1:hover > span:first-child:before {
  color: transparent;
  background-color: transparent;
}

.btn-fold-2 {
  position: relative;
  display: inline-block;
  width: 14rem;
  z-index: 1;
  font-family: 'Varela Round', sans-serif;
  color: white;
  text-decoration: none;
  font-size: 2.5rem;
  text-transform: uppercase;
  letter-spacing: 0.1rem;
  background-color: #0079c2;
  -webkit-transform-style: preserve-3d;
          transform-style: preserve-3d;
  -webkit-transform: translateX(0.5rem);
          transform: translateX(0.5rem);
  -webkit-transition: background-color 0s 0.2s ease-in-out;
  transition: background-color 0s 0.2s ease-in-out;
}
.btn-fold-2 span {
  position: relative;
  width: 50%;
  float: left;
  padding-top: 1rem;
  padding-bottom: .7rem;
  pointer-events: none;
  -webkit-transform-style: preserve-3d;
          transform-style: preserve-3d;
  -webkit-perspective: 400px;
          perspective: 400px;
  -webkit-perspective-origin: 50% 200%;
          perspective-origin: 50% 200%;
}
.btn-fold-2 span:after {
  position: absolute;
  top: 0;
  right: 0;
  bottom: 0;
  left: 0;
  -webkit-transition: opacity 0s 0.2s ease-in-out, -webkit-transform 0.4s;
  transition: opacity 0s 0.2s ease-in-out, -webkit-transform 0.4s;
  transition: transform 0.4s, opacity 0s 0.2s ease-in-out;
  transition: transform 0.4s, opacity 0s 0.2s ease-in-out, -webkit-transform 0.4s;
}
.btn-fold-2 span:first-child {
  z-index: 3;
  opacity: 1;
  text-align: right;
  background-color: #0079c2;
  box-shadow: -1rem 0 0 #0079c2;
  -webkit-transition: opacity 0s;
  transition: opacity 0s;
}
.btn-fold-2 span:first-child:after {
  content: 'ate';
  opacity: 1;
  padding-top: 1rem;
  text-align: left;
  background-color: #0079c2;
  -webkit-transform-origin: 0 50%;
          transform-origin: 0 50%;
  -webkit-transform: translateX(100%) rotateY(0);
          transform: translateX(100%) rotateY(0);
}
.btn-fold-2 span:last-child {
  z-index: 2;
  text-align: left;
  color: black;
  background-color: #fae900;
}
.btn-fold-2 span:last-child:after {
  content: 'don';
  opacity: 0;
  padding-top: 1rem;
  text-align: right;
  background-color: #fae900;
  box-shadow: -1rem 0 0 #fae900;
  -webkit-transform-origin: 100% 50%;
          transform-origin: 100% 50%;
  -webkit-transform: translateX(-100%) rotateY(180deg);
          transform: translateX(-100%) rotateY(180deg);
}
.btn-fold-2:hover {
  background-color: #fae900;
}
.btn-fold-2:hover > span:first-child {
  opacity: 0;
  -webkit-transition: opacity 0s 0.4s;
  transition: opacity 0s 0.4s;
}
.btn-fold-2:hover > span:first-child:after {
  opacity: 0;
  -webkit-transform: translateX(100%) rotateY(-180deg);
          transform: translateX(100%) rotateY(-180deg);
}
.btn-fold-2:hover > span:last-child:after {
  opacity: 1;
  -webkit-transform: translateX(-100%) rotateY(0.1deg);
          transform: translateX(-100%) rotateY(0.1deg);
}