* {
  box-sizing: border-box;
}

body {

  color: #000000;
  font: 1em 'PT Sans', sans-serif;
}

::selection {
  background-color: #51BB1E;
}

.tabbed {
  width: 1000px;
  margin: 0px auto;
}

.tabbed > input {
  display: none;
}

.tabbed > label {
  display: block;
  float: left;
  padding: 10px 15px;
  margin-right: 3px;
  cursor: pointer;
  transition: background-color .3s;
}

.tabbed > label:hover,
.tabbed > input:checked + label {
  background: #51BB1E;
}

.tabs {
  clear: both;
  perspective: 600px;
}

.tabs > div {
  height:356px;
  width: 1000px;
  position: absolute;
  border: 2px solid #51BB1E; /**edit color**/
  padding: 10px 30px 40px;
  line-height: 1.4em;
  opacity: 0;
  transform: rotateX(-20deg);
  transform-origin: top center;
  transition: opacity .3s, transform 1s;
  z-index: 0;
}

#tab-nav-1:checked ~ .tabs > div:nth-of-type(1),
#tab-nav-2:checked ~ .tabs > div:nth-of-type(2),
#tab-nav-3:checked ~ .tabs > div:nth-of-type(3),
#tab-nav-4:checked ~ .tabs > div:nth-of-type(4) {
  transform: rotateX(0);
  opacity: 1;
  z-index: 1;
}

@media screen and (max-width: 700px) {
  .tabbed {
    width: 400px;
  }

  .tabbed > label {
    display: none;
  }

  .tabs > div {
    width: 400px;
    border: none;
    padding: 0;
    opacity: 1;
    position: relative;
    transform: none;
    margin-bottom: 60px;
  }

  .tabs > div h2 {
    border-bottom: 2px solid #51BB1E; /**edit color**/
    padding-bottom: .5em;
  }
}