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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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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-.

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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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Packages

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Search for and use JavaScript packages from npm here. By selecting a package, an import statement will be added to the top of the JavaScript editor for this package.

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HTML 

              
                
  <input type="checkbox" id="switch" name="switch">
  <label for="switch" class="switch"></label>
!

CSS 

              
                @import "compass/css3";

*, *:after, *:before { 
  box-sizing: border-box;
}

#switch {
   visibility:hidden;
  clip:rect(0 0 0 0);
  position: absolute;
  left: 9999px;
}

.switch {
  display: block;
  width: 130px;
  height: 60px;
  margin: 70px auto; 
  position: relative;
  background: #ced8da; /* Old browsers */
  background: -moz-linear-gradient(left,  #ced8da 0%, #d8e0e3 29%, #ccd4d7 34%, #d4dcdf 62%, #fff9f4 68%, #e1e9ec 74%, #b7bfc2 100%); /* FF3.6+ */
  background: -webkit-gradient(linear, left top, right top, color-stop(0%,#ced8da), color-stop(29%,#d8e0e3), color-stop(34%,#ccd4d7), color-stop(62%,#d4dcdf), color-stop(68%,#fff9f4), color-stop(74%,#e1e9ec), color-stop(100%,#b7bfc2)); /* Chrome,Safari4+ */
  background: -webkit-linear-gradient(left,  #ced8da 0%,#d8e0e3 29%,#ccd4d7 34%,#d4dcdf 62%,#fff9f4 68%,#e1e9ec 74%,#b7bfc2 100%); /* Chrome10+,Safari5.1+ */
  background: -o-linear-gradient(left,  #ced8da 0%,#d8e0e3 29%,#ccd4d7 34%,#d4dcdf 62%,#fff9f4 68%,#e1e9ec 74%,#b7bfc2 100%); /* Opera 11.10+ */
  background: -ms-linear-gradient(left,  #ced8da 0%,#d8e0e3 29%,#ccd4d7 34%,#d4dcdf 62%,#fff9f4 68%,#e1e9ec 74%,#b7bfc2 100%); /* IE10+ */
  background: linear-gradient(to right,  #ced8da 0%,#d8e0e3 29%,#ccd4d7 34%,#d4dcdf 62%,#fff9f4 68%,#e1e9ec 74%,#b7bfc2 100%); /* W3C */
  filter: progid:DXImageTransform.Microsoft.gradient( startColorstr='#ced8da', endColorstr='#b7bfc2',GradientType=1 ); /* IE6-9 */
  transition: all 0.2s ease-out;
  cursor: pointer;
  border-radius: 0.35em;
  box-shadow: 
    0 0 1px 2px rgba(0,0,0,0.7),
    inset 0 2px 0 rgba(255,255,255,0.6),
    inset 0 -1px 0 1px rgba(0,0,0,0.3),
    0 8px 10px rgba(0,0,0,0.15);
}  

.switch:before {
  display:block;
  position: absolute;
 	left: -35px; right: -35px;
  top: -25px; bottom: -25px;
  z-index: -2;
  content: "";
  border-radius: 0.4em;
  background: #d5dde0;
  background: linear-gradient(#d7dfe2, #bcc7cd);
  box-shadow:
    inset 0 2px 0 rgba(255,255,255,0.6),
    inset 0 -1px 1px 1px rgba(0,0,0,0.3),
    0 0 8px 2px rgba(0,0,0,0.2),
    0 2px 4px 2px rgba(0,0,0,0.1);
  pointer-events: none;
  transition: all 0.2s ease-out;
}

.switch:after {
 	content: "";
  position: absolute;
  right: -25px;
  top: 50%;
  width: 16px;
  height: 16px;
  border-radius: 50%;
  background: #788b91;
  margin-top: -8px;
  z-index: -1;
  box-shadow: 
    inset 0 -1px 8px rgba(0,0,0,0.7),
    inset 0 -2px 2px rgba(0,0,0,0.2),
    0 1px 0 white,
    0 -1px 0 rgba(0,0,0,0.5),
    -47px 32px 15px 13px rgba(0,0,0,0.25);
}

#switch:checked ~ .switch {
  background: #b7bfc2; /* Old browsers */
  background: -moz-linear-gradient(left, #b7bfc2 0%, #e1e9ec 26%, #fff9f4 32%, #d4dcdf 38%, #ccd4d7 66%, #d8e0e3 71%, #ced8da 100%); /* FF3.6+ */
  background: -webkit-gradient(linear, left top, right top, color-stop(0%,#b7bfc2), color-stop(26%,#e1e9ec), color-stop(32%,#fff9f4), color-stop(38%,#d4dcdf), color-stop(66%,#ccd4d7), color-stop(71%,#d8e0e3), color-stop(100%,#ced8da)); /* Chrome,Safari4+ */
  background: -webkit-linear-gradient(left, #b7bfc2 0%,#e1e9ec 26%,#fff9f4 32%,#d4dcdf 38%,#ccd4d7 66%,#d8e0e3 71%,#ced8da 100%); /* Chrome10+,Safari5.1+ */
  background: -o-linear-gradient(left, #b7bfc2 0%,#e1e9ec 26%,#fff9f4 32%,#d4dcdf 38%,#ccd4d7 66%,#d8e0e3 71%,#ced8da 100%); /* Opera 11.10+ */
  background: -ms-linear-gradient(left, #b7bfc2 0%,#e1e9ec 26%,#fff9f4 32%,#d4dcdf 38%,#ccd4d7 66%,#d8e0e3 71%,#ced8da 100%); /* IE10+ */
  background: linear-gradient(to right, #b7bfc2 0%,#e1e9ec 26%,#fff9f4 32%,#d4dcdf 38%,#ccd4d7 66%,#d8e0e3 71%,#ced8da 100%); /* W3C */
  filter: progid:DXImageTransform.Microsoft.gradient( startColorstr='#b7bfc2', endColorstr='#ced8da',GradientType=1 ); /* IE6-9 */
}

#switch:checked ~ .switch:after {
 	background: #b1ffff;
  box-shadow: 
    inset 0 -1px 8px rgba(0,0,0,0.7),
    inset 0 -2px 2px rgba(0,0,0,0.2),
    0 1px 0 white,
    0 -1px 0 rgba(0,0,0,0.5),
    -110px 32px 15px 13px rgba(0,0,0,0.25); 
}
!

JS
!
999px

Console