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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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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

Add Packages

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#error
  div#box
  h3 ERROR 500
  p Things are a little #[span unstable] here
  p I suggest come back later
!

CSS 

              
                $color-1 = magenta;
$color-2 = cyan;

html,body
  height 100%;
  
body
  display grid;
  width 100%;
  font-family: Inconsolata, monospace;
    
  div#error
    position relative;
    margin auto; padding: 20px;
    z-index 2;
    
    div#box
      position absolute; top 0; left 0;
      width 100%; height 100%;
      border 1px solid #000;
      
      &:before, &:after
        content '';
        position absolute; top 0; left 0;
        width 100%; height 100%;
        box-shadow inset 0px 0px 0px 1px #000;
        mix-blend-mode: multiply;
        animation dance 2s infinite steps(1);
      
      &:before
        clip-path: polygon(0 0, 65% 0, 35% 100%, 0 100%)
        box-shadow inset 0px 0px 0px 1px currentColor;
        color $color-1;
      
      &:after
        clip-path: polygon(65% 0, 100% 0, 100% 100%, 35% 100%);
        animation-duration: 0.5s;
        animation-direction: alternate;
        box-shadow inset 0px 0px 0px 1px currentColor;
        color $color-2;
      
    h3
      position relative;
      font-size: 5vw; font-weight: 700;
      text-transform uppercase;
      animation: blink 1.3s infinite steps(1);
      
      &:before, &:after
        content 'ERROR 500';
        position absolute; top -1px; left 0;
        mix-blend-mode: soft-light;
        animation dance 2s infinite steps(2);
      
      &:before
          clip-path: polygon(0 0, 100% 0, 100% 50%, 0 50%)
          color: $color-1;
          animation: shiftright 200ms steps(2) infinite;
        &:after
          clip-path: polygon(0 100%, 100% 100%, 100% 50%, 0 50%)
          color: $color-2;
          animation: shiftleft 200ms steps(2) infinite;
    
    p
      position relative
      margin-bottom 8px;
      
      span
        position relative;
        display inline-block;
        font-weight: bold;
        color: #000;
        animation blink 3s steps(1) infinite;
        
        &:before, &:after
          content 'unstable';
          position absolute;
          top -1px; left 0;
          mix-blend-mode multiply;
          
        &:before
          clip-path: polygon(0 0, 100% 0, 100% 50%, 0 50%)
          color: $color-1;
          animation: shiftright 1.5s steps(2) infinite;
        &:after
          clip-path: polygon(0 100%, 100% 100%, 100% 50%, 0 50%)
          color: $color-2;
          animation: shiftleft 1.7s steps(2) infinite;
        
@keyframes dance
  0%, 84%, 94%
    transform skew(0deg);
  85%
    transform skew(5deg);
  90%
    transform skew(-5deg);
  98%
    transform skew(3deg);

@keyframes shiftleft
  0%, 87%, 100%
    transform translate(0,0) skew(0deg);
  84%, 90%
    transform translate(-8px,0) skew(20deg);

@keyframes shiftright
  0%, 87%, 100%
    transform translate(0,0) skew(0deg);
  84%, 90%
    transform translate(8px,0) skew(20deg);

@keyframes blink
  0%, 50%, 85%, 100%
    color #000;
  87%, 95%
    color transparent;
!

JS
!
999px

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