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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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Adding Classes

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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

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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 

              
                <h1 class="center">Random math formulas</h1>
<p class="center">Someone devs use MathJax, some use MathML<br>But plain HTML + CSS is enougth for good looking formulas</p>
<hr>
<div class="math showcase">
  x = <span class="frac">
    <span> - b &pm; <span class="sqrt">b<sup>2</sup> - 4ac</span></span>
    <span>2a</span>
  </span>
  <span class="annot">sqrt() was hard</span>
</div>

<div class="math showcase">
  braces = 
  <span class="surround round"><span class="frac"><span>round</span><span>is usual</span></span></span> + 
  <span class="surround square"><span class="frac"><span>square</span><span>matrix?</span></span></span> + 
  <span class="surround curly"><span class="frac"><span>curly</span><span>much better</span></span></span>
  <span class="annot">(:</span>
</div>

<div class="math showcase">
  <span class="cs">
    <sup>n</sup>
    <span class="big">∑</span>
    <sub>i = 0</sub>
  </span>
  i<sup>3</sup>
  = <span class="surround round"><span class="frac"><span>n(n+1)</span><span>2</span></span></span>
  <span class="annot">Sum</span>
</div>

<div class="math showcase">
  <span class="arrow">vector</span> = <span class="surround round vec"><span>1</span><span>2</span><span>-3</span></span>
  <span class="annot">Classic pseudo elem arrow</span>
</div>

<div class="math showcase">
  matrix = <span class="surround square matrix" style="--c: 3">
    <span>1</span><span>2</span><span>3</span>
    <span>4</span><span>5</span><span>6</span>
    <span>7</span><span>8</span><span>9</span>
  </span>
  <span class="annot">display: grid</span>
</div>

<div class="math showcase">
  <span class="surround sys matrix" style="--c: 5">
    <span>3x</span><span>+</span><span>5y</span><span>=</span><span>3</span>
    <span>7z</span><span>-</span><span>42x</span><span>=</span><span>6</span>
    <span>33y</span><span>-</span><span>z</span><span>=</span><span>9</span>
  </span>
  <span class="annot">...easy</span>
</div>
!

CSS 

              
                @import url('https://fonts.googleapis.com/css2?family=Roboto+Slab:wght@200;400&display=swap');
/* @import url('https://fonts.googleapis.com/css2?family=Vollkorn&display=swap');
/*https://fonts.gstatic.com/l/font?kit=BngbUXZYTXPIvIBgJJSb6s3BzlRRfKOFbvjoDISWbXZCW_uI-uaRQWEFwaRKkYmcMi91UqFKWZBmQvGh_gLqDegFSFuY&skey=a9ad6a4717e923f0&v=v16*/

@import url('https://fonts.googleapis.com/css2?family=Roboto+Slab:wght@200;400&display=swap&text=∑');

body {
  background: #263238;
  color: #B0BEC5;
  font-family: 'Roboto Slab', serif;
}

h1 {
  font-weight: 200;
  font-size: 2em;
  color: #c792ea;
}

.center {
  text-align: center;
}

hr {
  width: 200px;
  border: 1px solid #2E3C43;
  position: relative;
  margin: 50px auto;
}

hr::before {
  content: '***';
  position: absolute;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
  padding: 10px;
  background: #263238;
  display: block;
  color: #607D8B;
}

.showcase {
  padding: 15px;
  text-align: center;
  position: relative;
}

.math {
  font-family: 'Roboto Slab', serif;
}

.math .small {
  font-size: 0.7em;
}

.math .frac {
  display: inline-flex;
  vertical-align: middle;
  flex-direction: column;
  text-align: center;
  margin-top: -1px;
}

.math .frac > *:first-child {
  border-bottom: 2px solid currentColor;
  padding-bottom: 5px;
}

.math .frac > *:last-child {
  padding-top: 5px;
}

.math .frac > * {
  padding: 0 0.5em;
}

.math .sqrt {
  border-top: 2px solid currentColor;
  margin-left: 10px;
  padding-left: 5px;
  position: relative;
  display: inline-block;
}

.math .sqrt::before {
  content: '';
  position: absolute;
  top: -2px;
  left: -10px;
  bottom: 0px;
  width: 10px;
  background: currentColor;
  clip-path: polygon(
    0 50%,
    2px 50%,
    50% calc(100% - 2px),
    calc(100% - 2px) 0,
    100% 0,
    100% 2px,
    calc(50% + 2px) 100%,
    calc(50% - 2px) 100%,
    0 calc(50% + 2px)
  );
}

.surround {
  padding: 0 10px;
  position: relative;
  display: inline-block;
  --round: 5px;
  --off: 0;
}

.surround::before {
  content: '';
  width: 5px;
  position: absolute;
  top: 0px;
  left: var(--off);
  bottom: 0px;
  width: 5px;
  border-top: 2px solid currentColor;
  border-bottom: 2px solid currentColor;
  border-left: 2px solid currentColor;
  border-top-left-radius: var(--round);
  border-bottom-left-radius: var(--round);
}

.surround::after {
  content: '';
  width: 5px;
  position: absolute;
  top: 0px;
  right: var(--off);
  bottom: 0px;
  width: 5px;
  border-top: 2px solid currentColor;
  border-bottom: 2px solid currentColor;
  border-right: 2px solid currentColor;
  border-top-right-radius: var(--round);
  border-bottom-right-radius: var(--round);
}

.surround.round {
  --round: 10px 30px;
}

.surround.square {
  --round: 0;
}

.surround.curly {
  --round: 10px;
  --off: 5px;
  padding: 0 15px;
  background-image: 
    linear-gradient(0deg, currentColor 25%, currentColor 25%),
    linear-gradient(0deg, currentColor 25%, currentColor 25%);
  background-repeat: no-repeat;
  background-size: 5px 2px;
  background-position: 0 center, 100% center;
}

.surround.sys {
  --round: 10px;
  --off: 5px;
  padding: 0 15px;
  background-image: 
    linear-gradient(0deg, currentColor 25%, currentColor 25%);
  background-repeat: no-repeat;
  background-size: 5px 2px;
  background-position: 0 center;
}

.surround.sys::after {
  content: unset;
}

.cs {
  position: relative;
  display: inline-block;
}

.cs > sup {
  position: absolute;
  bottom: calc(100% - 10px);
  left: 50%;
  transform: translate(-50%);
  width: max-content;
}

.cs > sub {
  position: absolute;
  top: calc(100% - 5px);
  left: 50%;
  transform: translate(-50%);
  width: max-content;
}

.big {
  font-size: 2em;
  font-weight: 200;
}

.arrow {
  position: relative;
}

.arrow::before {
  content: '';
  position: absolute;
  bottom: calc(100% + 5px);
  left: 0;
  right: 0;
  height: 2px;
  background: currentColor;
}

.arrow::after {
  content: '';
  position: absolute;
  bottom: calc(100% - 1px);
  right: -1px;
  height: 5px;
  width: 5px;
  border-top: 2px solid currentColor;
  border-right: 2px solid currentColor;
  transform-origin: top right;
  transform: rotate(45deg);
}

.surround.vec {
  display: inline-flex;
  flex-direction: column;
  vertical-align: middle;
}

.matrix {
  display: inline-grid;
  grid-template-columns: repeat(var(--c), 1fr);
  grid-gap: 5px;
  padding: 5px 15px;
  vertical-align: middle;
}

.annot {
  color: #607D8B;
  position: absolute;
  right: 15px;
  top: calc(50% - 0.5em);
}
!

JS
!
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