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HTML

About HTML Preprocessors

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

In CodePen, whatever you write in the HTML editor is what goes within the <body> tags in a basic HTML5 template. So you don't have access to higher-up elements like the <html> tag. If you want to add classes there that can affect the whole document, this is the place to do it.

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.

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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-.

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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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 

              
                <div class="toggle-container">
  <input class="toggle-input" type="checkbox">
  <svg class="toggle" viewBox="0 0 292 142" xmlns="http://www.w3.org/2000/svg">
    <path class="toggle-background" d="M71 142C31.7878 142 0 110.212 0 71C0 31.7878 31.7878 0 71 0C110.212 0 119 30 146 30C173 30 182 0 221 0C260 0 292 31.7878 292 71C292 110.212 260.212 142 221 142C181.788 142 173 112 146 112C119 112 110.212 142 71 142Z" />
    <rect class="toggle-icon on" x="64" y="39" width="12" height="64" rx="6" />
    <path class="toggle-icon off" fill-rule="evenodd" d="M221 91C232.046 91 241 82.0457 241 71C241 59.9543 232.046 51 221 51C209.954 51 201 59.9543 201 71C201 82.0457 209.954 91 221 91ZM221 103C238.673 103 253 88.6731 253 71C253 53.3269 238.673 39 221 39C203.327 39 189 53.3269 189 71C189 88.6731 203.327 103 221 103Z" />
    <g filter="url('#goo')">
      <rect class="toggle-circle-center" x="13" y="42" width="116" height="58" rx="29" fill="#fff"/>
      <rect class="toggle-circle left" x="14" y="14" width="114" height="114" rx="58" fill="#fff" />
      <rect class="toggle-circle right" x="164" y="14" width="114" height="114" rx="58" fill="#fff" />
    </g>
    <filter id="goo">
      <feGaussianBlur in="SourceGraphic" result="blur" stdDeviation="10" />
      <feColorMatrix in="blur" mode="matrix" values="1 0 0 0 0  0 1 0 0 0  0 0 1 0 0  0 0 0 18 -7" result="goo" />
    </filter>
  </svg>
</div>

<div class="toggle-container">
  <input class="toggle-input" type="checkbox" checked>
  <svg class="toggle" viewBox="0 0 292 142" xmlns="http://www.w3.org/2000/svg">
    <path class="toggle-background" d="M71 142C31.7878 142 0 110.212 0 71C0 31.7878 31.7878 0 71 0C110.212 0 119 30 146 30C173 30 182 0 221 0C260 0 292 31.7878 292 71C292 110.212 260.212 142 221 142C181.788 142 173 112 146 112C119 112 110.212 142 71 142Z" />
    <rect class="toggle-icon on" x="64" y="39" width="12" height="64" rx="6" />
    <path class="toggle-icon off" fill-rule="evenodd" d="M221 91C232.046 91 241 82.0457 241 71C241 59.9543 232.046 51 221 51C209.954 51 201 59.9543 201 71C201 82.0457 209.954 91 221 91ZM221 103C238.673 103 253 88.6731 253 71C253 53.3269 238.673 39 221 39C203.327 39 189 53.3269 189 71C189 88.6731 203.327 103 221 103Z" />
    <g filter="url('#goo')">
      <rect class="toggle-circle-center" x="13" y="42" width="116" height="58" rx="29" fill="#fff"/>
      <rect class="toggle-circle left" x="14" y="14" width="114" height="114" rx="58" fill="#fff" />
      <rect class="toggle-circle right" x="164" y="14" width="114" height="114" rx="58" fill="#fff" />
    </g>
    <filter id="goo">
      <feGaussianBlur in="SourceGraphic" result="blur" stdDeviation="10" />
      <feColorMatrix in="blur" mode="matrix" values="1 0 0 0 0  0 1 0 0 0  0 0 1 0 0  0 0 0 18 -7" result="goo" />
    </filter>
  </svg>
</div>
!

CSS 

              
                body {
  display: flex;
  flex-direction: column;
  justify-content: center;
  align-items: center;
  min-height: 100vh;
  font-size: 2em; // resize for demo
  gap: 1em;
}

@function em($pixels) {
  @if not (unit($pixels) == 'px') {
    @error 'Value #{$pixels} must have `px` unit.';
  }
  
  @return $pixels / 16px * 1em;
}

.toggle-container {
  --inactive-color: #d3d3d6;
  position: relative;
  aspect-ratio: 292 / 142;
  height: em(30px);
  
  &:nth-child(1) {
    --active-color: #35c759;
  }
  
  &:nth-child(2) {
    --active-color: #1868e3;
  }
}

.toggle-input {
  appearance: none;
  margin: 0;
  position: absolute;
  z-index: 1;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  cursor: pointer;
}

.toggle {
  width: 100%;
  height: 100%;
  overflow: visible;
}

.toggle-background {
  fill: var(--inactive-color);
  transition: fill .4s;
  
  .toggle-input:checked + .toggle & {
    fill: var(--active-color);
  }
}

.toggle-circle-center {
  transform-origin: center;
  transition: transform .6s;

  .toggle-input:checked + .toggle & {
    transform: translateX(150px);
  }
}

.toggle-circle {
  transform-origin: center;
  backface-visibility: hidden;
  transition: transform .45s;
  
  &.left {
    transform: scale(1);
    
    .toggle-input:checked + .toggle & {
      transform: scale(0);
    }
  }
  
  &.right {
    transform: scale(0);
    
    .toggle-input:checked + .toggle & {
      transform: scale(1);
    }
  }
}

.toggle-icon {
  transition: fill .4s;

  &.on {
    fill: var(--inactive-color);

    .toggle-input:checked + .toggle & {
      fill: #fff;
    }
  }

  &.off {
    fill: #eaeaec;

    .toggle-input:checked + .toggle & {
      fill: var(--active-color);
    }
  }
}

// to do: absolute units for transform origins
!

JS
!
999px

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