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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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HTML 

              
                <p>
  青背景の子要素が、赤背景の親要素の上から50％・左から50％に配置されています。これがpositionを使った配置です。
</p>
<div class="position">
  <div class="parent">
    <div class="child"></div>
  </div>
</div>
<p>要素が横に並べられていきます。これがflexを用いた配置です。</p>
<div class="flex">
  <div></div>
  <div></div>
  <div></div>
</div>
<p>
  要素を自由に配置し、間に空白を設けたり、要素を伸ばしたりもできます。これがグリッドレイアウトです。
</p>
<div class="grid">
  <div class="first"></div>
  <div class="second"></div>
  <div class="third"></div>
</div>
!

CSS 

              
                .normal div {
  width: 100px;
  height: 100px;
  background-color: grey;
  margin-bottom: 5px;
}

.position {
  margin-bottom: 50px;
}
.position .parent {
  width: 100px;
  height: 100px;
  background-color: red;
  position: relative;
}
.position .parent .child {
  position: absolute;
  width: 80px;
  height: 80px;
  background-color: blue;
  -webkit-animation: slideposition 2s linear forwards;
          animation: slideposition 2s linear forwards;
}

@-webkit-keyframes slideposition {
  from {
    top: 0%;
    left: 0%;
  }
  to {
    top: 50%;
    left: 50%;
  }
}

@keyframes slideposition {
  from {
    top: 0%;
    left: 0%;
  }
  to {
    top: 50%;
    left: 50%;
  }
}
.flex {
  display: -webkit-box;
  display: -ms-flexbox;
  display: flex;
  gap: 5px;
}
.flex div {
  width: 100px;
  height: 100px;
  background-color: grey;
  margin-bottom: 5px;
}

.grid {
  width: 300px;
  height: 300px;
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  grid-template-rows: repeat(3, 1fr);
  gap: 5px;
  -webkit-transition: 2s;
  transition: 2s;
}
.grid div {
  background-color: grey;
}
.grid .first {
  grid-column: 1/2;
  grid-row: 1/2;
  -webkit-animation: grid-anim-1 2s linear infinite;
          animation: grid-anim-1 2s linear infinite;
}
.grid .second {
  grid-column: 2/3;
  grid-row: 1/3;
  background-color: green;
}
.grid .third {
  grid-column: 2/4;
  grid-row: 3/4;
  background-color: aqua;
}

@-webkit-keyframes grid-anim-1 {
  from {
    grid-row: 1/2;
  }
  to {
    grid-row: 1/4;
  }
}

@keyframes grid-anim-1 {
  from {
    grid-row: 1/2;
  }
  to {
    grid-row: 1/4;
  }
}
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JS
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999px

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