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                <div class="tab_contents">
  <input id="tab-1" type="radio" name="tab_item" checked>
  <label class="tab_item" for="tab-1">tab 1</label>
  <input id="tab-2" type="radio" name="tab_item">
  <label class="tab_item" for="tab-2">tab 2</label>
  <input id="tab-3" type="radio" name="tab_item">
  <label class="tab_item" for="tab-3">tab 3</label>
  <div class="clear"></div>
  <div id="tab-b1">
    <h1>tab 1 contents</h4>
  <div id="tab-b2">
    <h1>tab 2 contents</h4>
  <div id="tab-b3">
    <h1>tab 3 contents</h4>


  width: 100%
    display: inline-block
    margin: 0
    padding: 0
    box-sizing: border-box
    display: block
    float: left
    width: calc((100% - 2em) / 3)
    cursor: pointer
    background: white
    border: #6eaa2e 1px solid
    color: #6eaa2e
    transition: .2s
    text-align: center
    letter-spacing: .2em
    padding: 1em
    margin-top: .4em
      margin-left: 1em
    @media only screen and (max-width:750px)
      width: calc((100% - 1.2em) / 3)
      padding: .5em 1em
        margin-left: .4em
      background: #6eaa2e
      color: white
  input:checked + label
    background: #6eaa2e
    color: white
      top: 1.2em
      bottom: 1.2em
    margin-top: 0
      margin-left: 1em
    @media only screen and (max-width:750px)
      padding: .5em 1em
      margin-top: .4em
    display: none
    display: none
  #tab-1:checked ~ #tab-b1,
  #tab-2:checked ~ #tab-b2,
  #tab-3:checked ~ #tab-b3,
  #tab-4:checked ~ #tab-b4
    display: block
      content: ''
      display: block
      clear: both