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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

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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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Using packages here is powered by Skypack, which makes packages from npm not only available on a CDN, but prepares them for native JavaScript ES6 import usage.

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HTML 

              
                .panel
  fieldset
    legend justify-content
    select(name='jc')
      each val in ['stretch', 'start', 'end', 'flex-start', 'flex-end', 'left', 'right', 'center', 'space-between', 'space-around', 'space-evenly']
        option(value=''+val)
          =val
  fieldset
    legend align-content
    select(name='ac')
      each val in ['stretch', 'start', 'end', 'flex-start', 'flex-end', 'left', 'right', 'center', 'space-between', 'space-around', 'space-evenly']
        option(value=''+val)
          =val

.container#grid
  each val in ['Раз контент', 'Два контент', 'Три контент', 'Четыре контент', 'Контент справа налево','Еще контент']
    .item
      =val
    .helper
!

CSS 

              
                
.container {
  width: 500px;
  height: 380px;
  border: 1px solid green;
}
#grid {
  display: grid;
  grid: repeat(2, auto) / repeat(3, auto);
}
#flex {
  display: flex;
  flex-flow: row wrap;
}
.item {
  background: rgba(255,160,160,.5);
  border: 1px solid rgba(255,0,0,.5);
}
#flex .item:nth-child(5), #grid .item:nth-child(9) {
  direction: rtl;
  background: rgba(160,255,160,.5);
  border: 1px solid rgba(0,255,0,.5);
}
.tb {
  writing-mode: tb-rl;
}
.helper {
  background: #ccc;
  justify-self: stretch;
  align-self: stretch;
  border: 1px solid #888;
  z-index: -1;
}
@for $i from 0 through 1 {
  @for $j from 0 through 2 {
    .item:nth-child(#{($i * 3 + $j) * 2 + 1}), .helper:nth-child(#{($i * 3 + $j) * 2 + 2}) {
      grid-row: #{$i + 1};
      grid-column: #{$j + 1};
    }
  }
}

.panel {
  display: flex;
  margin-bottom: 1em;
  justify-content: space-between;
}
ul {
  list-style: none;
  padding: 0;
}
body {
  width: 550px;
}
!

JS 

              
                const properties = {
  jc: 'justify-content',
  ac: 'align-content',
  ji: 'justify-items',
  ai: 'align-items',
  js: 'justify-self',
  as: 'align-self'
}

for (let key in properties) {
  let controls = document.getElementsByName(key);

  controls.forEach(function(item) {
    if (key === 'as' || key === 'js' ) {
      item.addEventListener('change', event=>{
        console.log(event.target.parentNode.parentNode)
        event.target.parentNode.parentNode.style.setProperty(properties[key],event.target.value);
      });
    }
    else {
      item.addEventListener('change', event=>{
        document.getElementById('grid').style.setProperty(properties[key],event.target.value);
        document.getElementById('flex').style.setProperty(properties[key],event.target.value);
      })
    }
  });
}
!
999px

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