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HTML

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HTML preprocessors can make writing HTML more powerful or convenient. For instance, Markdown is designed to be easier to write and read for text documents and you could write a loop in Pug.

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Adding Classes

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About the <head>

In CodePen, whatever you write in the HTML editor is what goes within the <body> tags in a basic HTML5 template. If you need things in the <head> of the document, put that code here.

!
Insecure Resource

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CSS

About CSS Preprocessors

CSS preprocessors help make authoring CSS easier. All of them offer things like variables and mixins to provide convenient abstractions.

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CSS Base

About CSS Base

It's a common practice to apply CSS to a page that styles elements such that they are consistent across all browsers. We offer two of the most popular choices: normalize.css and a reset. Or, choose Neither and nothing will be applied.

Vendor Prefixing

About Vendor Prefixing

To get the best cross-browser support, it is a common practice to apply vendor prefixes to CSS properties and values that require them to work. For instance -webkit- or -moz-.

We offer two popular choices: Autoprefixer (which processes your CSS server-side) and -prefix-free (which applies prefixes via a script, client-side).

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JavaScript

About JavaScript Preprocessors

JavaScript preprocessors can help make authoring JavaScript easier and more convenient.

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Babel includes JSX processing.

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HTML 

              
                <link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.4/css/bootstrap.min.css">

<body>
  <div class="container">
    <article class="tabs">
      <ul class="nav nav-tabs nav-tabs-redBorders">
        <li class="active">
          <a data-toggle="tab" href="#home">
            Tab 1 
          </a>
        </li>
        <li>
          <a data-toggle="tab" href="#menu1">
            Tab 2
          </a>
        </li>
      </ul>
      <div class="tab-content">
        <!--tab1 - home-->
        <div id="home" class="tab-pane fade in active">
          <!-- 
==============================
bootstrap accordion
==============================
-->
          <div class="panel-group" id="accordion1" role="tablist" aria-multiselectable="true">
            <!--panel-default-->
            <div class="panel panel-default">
              <div class="panel-heading" role="tab" id="headingOne">
                <h3 class="panel-title">
                  <a role="button" data-toggle="collapse" data-parent="#accordion1" href="#collapseOne" aria-expanded="true" aria-controls="collapseOne">
                    <i class="fa fa-minus more-less" aria-hidden="true"></i>
                    An singulis consequat intellegat eos
                  </a>
                </h3>
              </div>
              <div id="collapseOne" class="panel-collapse collapse in" role="tabpanel" aria-labelledby="headingOne">
                <div class="panel-body">
                  <p>
                    Discere insolens et est. Id prompta rationibus definiebas per. Te mei partem civibus, vix elit soleat possim ex. Minim timeam audire no sea, erant partem dicunt ex cum. Mei cu ullum sapientem, probo blandit has at.<br><br>
                    An singulis consequat intellegat eos. Nec elit falli propriae no, ius incorrupte repudiandae ut. Nam ne amet omnes, numquam docendi ius ut. Partem persequeris pri in. An incorrupte complectitur mediocritatem vis, sea nostro salutandi et.<br><br>
                    Vis ex purto exerci interesset, mei eius civibest. Id prompta rationibus definiebas per. Te mei partem civibus, vix elit soleat possim ex. Minim timeam audire no sea, erant partem dicunt ex cum. Mei cu ullum sapientem, probo blandit has at.
                  </p>
                </div>
              </div>
            </div>
            <!--panel-2-->
            <div class="panel panel-default">
              <div class="panel-heading" role="tab" id="headingTwo">
                <h3 class="panel-title">
                  <a class="collapsed" role="button" data-toggle="collapse" data-parent="#accordion1" href="#collapseTwo" aria-expanded="false" aria-controls="collapseTwo">
                    <i class="fa fa-plus more-less" aria-hidden="true"></i>
                    Probo laoreet officiis mei ei, sale civibus pro no, te vel partem docendi?
                  </a>
                </h3>
              </div>
              <div id="collapseTwo" class="panel-collapse collapse" role="tabpanel" aria-labelledby="headingTwo">
                <div class="panel-body">
                  <p>
                    3 wolf moon officia aute, non cupidatat skateboard dolor brunch. Food truck quinoa nesciunt laborum eiusmod. Brunch 3 wolf moon tempor, sunt aliqua put a bird on it squid single-origin coffee nulla assumenda shoreditch et. Nihil anim keffiyeh helvetica, craft beer labore wes anderson cred nesciunt sapiente ea proident. Ad vegan excepteur butcher vice lomo. Leggings occaecat craft beer farm-to-table, raw denim aesthetic synth nesciunt you probably haven't heard of them accusamus labore sustainable VHS.
                  </p>
                </div>
              </div>
            </div>
            <!--panel-3-->
            <div class="panel panel-default">
              <div class="panel-heading" role="tab" id="headingThree">
                <h3 class="panel-title">
                  <a class="collapsed" role="button" data-toggle="collapse" data-parent="#accordion1" href="#collapseThree" aria-expanded="false" aria-controls="collapseThree">
                    <i class="fa fa-plus more-less" aria-hidden="true"></i>
                    Mucius quodsi dissentiunt in vel. Est postulant contentiones ea, nobis inermis id duo?
                  </a>
                </h3>
              </div>
              <div id="collapseThree" class="panel-collapse collapse" role="tabpanel" aria-labelledby="headingThree">
                <div class="panel-body">
                  <p>
                    Anim pariatur cliche reprehenderit, enim eiusmod high life accusamus terry richardson ad squid. 3 wolf moon officia aute, non cupidatat skateboard dolor brunch. Food truck quinoa nesciunt laborum eiusmod. Brunch 3 wolf moon tempor, sunt aliqua put a bird on it squid single-origin coffee nulla assumenda shoreditch et. Nihil anim keffiyeh helvetica, craft beer labore wes anderson cred nesciunt sapiente ea proident. Ad vegan excepteur butcher vice lomo. Leggings occaecat craft beer farm-to-table, raw denim aesthetic synth nesciunt you probably haven't heard of them accusamus labore sustainable VHS.
                  </p>
                </div>
              </div>
            </div>
          </div>
          <!-- end
==============================
bootstrap accordion
==============================
-->
        </div>
        <!--tab2-->
        <div id="menu1" class="tab-pane fade">
          <!-- 
==============================
bootstrap accordion
==============================
-->
          <div class="panel-group" id="accordion2" role="tablist" aria-multiselectable="true">
            <!--panel-default-->
            <div class="panel panel-default">
              <div class="panel-heading" role="tab" id="headingOne_2">
                <h3 class="panel-title">
                  <a role="button" data-toggle="collapse" data-parent="#accordion2" href="#collapseOne2" aria-expanded="true" aria-controls="collapseOne2">
                    <i class="fa fa-minus more-less" aria-hidden="true"></i>
                    Dicta facilisis sea, quando comprehensam vituperatoribus eu ius
                  </a>
                </h3>
              </div>
              <div id="collapseOne2" class="panel-collapse collapse in" role="tabpanel" aria-labelledby="headingOne">
                <div class="panel-body">
                  <p>
                    Discere insolens et est. Id prompta rationibus definiebas per. Te mei partem civibus, vix elit soleat possim ex. Minim timeam audire no sea, erant partem dicunt ex cum. Mei cu ullum sapientem, probo blandit has at.<br><br>
                    An singulis consequat intellegat eos. Nec elit falli propriae no, ius incorrupte repudiandae ut. Nam ne amet omnes, numquam docendi ius ut. Partem persequeris pri in. An incorrupte complectitur mediocritatem vis, sea nostro salutandi et. Vis ex purto exerci interesset, mei eius civibus evertitur et. Consul iriure appetere at sed. Te qui modo propriae temporibus, illud modus mei cu. Epicurei adipisci no eum, cum iuvaret probatus deseruisse ei. Deleniti pericula cum ne, ea exerci complectitur est. Summo indoctum nec ut. Discere insolens et est. Id prompta rationibus definiebas per. Te mei partem civibus, vix elit soleat possim ex. Minim timeam audire no sea, erant partem dicunt ex cum. Mei cu ullum sapientem, probo blandit has at.
                  </p>
                </div>
              </div>
            </div>
            <!--panel-2-->
            <div class="panel panel-default">
              <div class="panel-heading" role="tab" id="headingTwo_2">
                <h3 class="panel-title">
                  <a class="collapsed" role="button" data-toggle="collapse" data-parent="#accordion2" href="#collapseTwo2" aria-expanded="false" aria-controls="collapseTwo2">
                    <i class="fa fa-plus more-less" aria-hidden="true"></i>
                    Probo laoreet officiis mei ei, sale civibus pro no, te vel partem docendi?
                  </a>
                </h3>
              </div>
              <div id="collapseTwo2" class="panel-collapse collapse" role="tabpanel" aria-labelledby="headingTwo">
                <div class="panel-body">
                  <p>
                    3 wolf moon officia aute, non cupidatat skateboard dolor brunch. Food truck quinoa nesciunt laborum eiusmod. Brunch 3 wolf moon tempor, sunt aliqua put a bird on it squid single-origin coffee nulla assumenda shoreditch et. Nihil anim keffiyeh helvetica, craft beer labore wes anderson cred nesciunt sapiente ea proident. Ad vegan excepteur butcher vice lomo. Leggings occaecat craft beer farm-to-table, raw denim aesthetic synth nesciunt you probably haven't heard of them accusamus labore sustainable VHS.
                  </p>
                </div>
              </div>
            </div>
            <!--panel-3-->
            <div class="panel panel-default">
              <div class="panel-heading" role="tab" id="headingThree_2">
                <h3 class="panel-title">
                  <a class="collapsed" role="button" data-toggle="collapse" data-parent="#accordion2" href="#collapseThree2" aria-expanded="false" aria-controls="collapseThree2">
                    <i class="fa fa-plus more-less" aria-hidden="true"></i>
                    Mucius quodsi dissentiunt in vel. Est postulant contentiones ea, nobis inermis id duo?
                  </a>
                </h3>
              </div>
              <div id="collapseThree2" class="panel-collapse collapse" role="tabpanel" aria-labelledby="headingThree">
                <div class="panel-body">
                  <p>
                    Anim pariatur cliche reprehenderit, enim eiusmod high life accusamus terry richardson ad squid. 3 wolf moon officia aute, non cupidatat skateboard dolor brunch. Food truck quinoa nesciunt laborum eiusmod. Brunch 3 wolf moon tempor, sunt aliqua put a bird on it squid single-origin coffee nulla assumenda shoreditch et. Nihil anim keffiyeh helvetica, craft beer labore wes anderson cred nesciunt sapiente ea proident. Ad vegan excepteur butcher vice lomo. Leggings occaecat craft beer farm-to-table, raw denim aesthetic synth nesciunt you probably haven't heard of them accusamus labore sustainable VHS.
                  </p>
                </div>
              </div>
            </div>
          </div>
          <!-- end
          ==============================
          bootstrap accordion
          ==============================
          -->
        </div>
      </div>
    </article>
  </div>

  <!-- Latest compiled and minified JavaScript -->
  <script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.3/jquery.min.js"></script>
  <script src="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.4/js/bootstrap.min.js"></script>
</body>
!

CSS 

              
                $brand-primary: red;
$gray-dark:#ccc;
.nav-tabs-redBorders{
    border-bottom: 1px solid $brand-primary;
    margin-top: 50px;
    > li{
        float: right;
        >a {
            border-radius: 0;
            border: solid $brand-primary 1px;
            border-bottom-color: transparent;
            font-size: 12px;
            text-transform: uppercase;
            font-weight: 700;
            position: relative;
            color: $gray-dark;
            &:hover {
              text-decoration: none;
          }
        }
    }
    li.active{
        > a,
        > a:focus, 
        > a:hover {
            color: $gray-dark;
            border: solid $brand-primary 1px;
            border-bottom-color: transparent;
            cursor: default;
            text-decoration: none;
            &:before{
                content: " ";
                position: absolute;
                width: 100%;
                height: 3px;
                background: $brand-primary;
                top: 0;
                left: 0;
            }
        }
    }
}
!

JS 

              
                //==================================
//    ACCORDION WITH TOGGLE ICONS
//==================================
function toggleIcon(e) {
  $(e.target)
    .prev('.panel-heading')
    .find(".more-less")
    .toggleClass('fa-plus fa-minus');
}
$('.panel-group').on('hidden.bs.collapse', toggleIcon);
$('.panel-group').on('shown.bs.collapse', toggleIcon);
!
999px

Console