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HTML

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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

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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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HTML 

              
                <header>
  <h1><a href="https://codepen.io/knoa/full/BaNBvRO">カモレレロ変換器 <small>Electroharmonix Converter</small></a></h1>
  <p>Hello と打てば、カモレレロ と変換します。</p>
</header>
<textarea id="from" placeholder="Hello"></textarea>
<textarea id="to" placeholder="カモレレロ"></textarea>
<footer>
  <p>カモレレロ変換器は、<a href="http://typodermicfonts.com/electroharmonix/" target="_top">Electroharmonix</a> フォントの字形を元に、日本の文字で表現しきれない一部の文字を独自にアレンジして作られています。</p>
  <p>入力された内容はどこにも送信されずお手元のコンピュータ上で変換されるので、絶対に日本人に読まれたくない極秘スパイ暗号などにも安心してご利用いただけます。</p>
  <address>Twitter: <a href="https://twitter.com/kantankikaku" target="_top">@kantankikaku</a> <a href="https://twitter.com/hashtag/%E3%82%AB%E3%83%A2%E3%83%AC%E3%83%AC%E3%83%AD%E5%A4%89%E6%8F%9B%E5%99%A8" target="_top">#カモレレロ変換器</a></address>
</footer>
!

CSS 

              
                header{
  background: royalblue;
  padding: 1px;
}
header h1{
  font-size: 200%;
  font-weight: bold;
  margin: 1vw 1vw 0 calc(1vw - .05em);
}
header h1 a{
  color: white !important;
  text-decoration: none !important;
}
header h1 a small{
  color: lightgray;
  margin-left: .5em;
}
header p{
  color: white;
  font-size: 90%;
  margin: .5vw 1vw .25vw;
}
p, textarea{
  margin: 1vw;
}
textarea{
  width: 80vw;
  height: 5em;
}
footer{
  font-size: 80%;
  text-align: left;
  color: gray;
}
footer p,
footer address{
  margin: .1em 1vw;
}
!

JS 

              
                const ALPHABET = 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789*#,.!? ';
const ELECTRISH = 'ム乃匸ワモチ彑カエ丁ケレ巾冂ロアＱ尺丂ナ凵レ山メソ乙ム乃匸ワモチ彑カエ丁ケレ巾冂ロアＱ尺丂ナ凵レ山メソ乙ロ亻己ヨ丩丂石フ日夕米井、。！？　';
const MAP = {};
Array.from(ALPHABET).forEach((c, i) => MAP[c] = ELECTRISH[i]);
let from = document.querySelector('textarea#from');
let to = document.querySelector('textarea#to');
from.addEventListener('input', function(e){
  to.value = Array.from(from.value).map(c => MAP[c] || c).join('');
});
!
999px

Console