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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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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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HTML 

              
                <article dir="ltr">
  <figure id="box_model">
    Content Box
    <span class="vertical scrollbar"></span>
    <span class="horizontal scrollbar"></span>
  </figure>
</article>

<form action="">
  <label for="show_scrollbars">Show scrollbars?</label>
  <input id="show_scrollbars" type="checkbox">
  
  <label for="inline_scrollbars">Inline scrollbars?</label>
  <input id="inline_scrollbars" type="checkbox">
</form>
!

CSS 

              
                body {
  min-height: 100vh;
  display: flex;
  align-items: center;
  justify-content: center;
  flex-direction: column;
  /*  scale the whole thing here  */
  font-size: min(2vmax, 2rem);
  gap: 0 5vmin;
}

@media (orientation: landscape) {
  body {
    flex-direction: row;
  }
}

article {
  background: repeating-linear-gradient(-45deg, hsl(0 0% 70%), hsl(0 0% 70%) 1px, white 1px, white 10px);
  box-shadow: 0 2.8px 2.2px rgba(0, 0, 0, 0.02),
    0 6.7px 5.3px hsl(0 0% 0% / .028),
    0 12.5px 10px hsl(0 0% 0% / .035),
    0 22.3px 17.9px hsl(0 0% 0% / .042),
    0 41.8px 33.4px hsl(0 0% 0% / .05),
    0 100px 80px hsl(0 0% 0% / .07);
  position: relative;
}

article::before {
  content: "Margin Box";
  position: absolute;
  top: 1ex;
  left: 50%;
  transform: translateX(-50%);
  height: 3ex;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: .5em;
  background: white;
  padding: .25rem 1rem;
  border-radius: 3rem;
}

article::after {
  content: "Outline & Box Shadow";
  position: absolute;
  top: 6ex;
  left: 0;
  width: 100%;
  height: 6ex;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: .5em;
  color: white;
}

figure {
  width: 25vmin;
  height: 25vmin;
  display: flex;
  align-items: center;
  justify-content: center;
  margin: 6ex;
  border: 3ex solid black;
  outline: 3ex solid hsl(270 50% 40% / 80%);
	padding: 3ex;
	background:
		linear-gradient(white, white) content-box,
		linear-gradient(hotpink, hotpink) padding-box;
  position: relative;
}

figure > .scrollbar {
  background: hsl(0 0% 0% / 25%);
  position: absolute;
  visibility: hidden;
}

figure > .scrollbar.vertical {
  width: 1ex;
  height: 100%;
  top: 0;
  right: 0;
}

figure > .scrollbar.horizontal {
  height: 1ex;
  width: 100%;
  bottom: 0;
  left: 0;
}

figure[scrollbars="true"] .scrollbar {
  visibility: visible;
}

figure[inline-scrollbars="true"] {
  padding: 3ex 4ex 4ex 3ex;
}

figure::after {
  content: "Padding Box";
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 6ex;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: .5em;
}

figure::before {
  content: "Border Box";
  color: white;
  position: absolute;
  top: 0;
  left: 0;
  transform: translateY(-100%);
  width: 100%;
  height: 6ex;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: .5em;
}

form {
  display: grid;
  grid-template-columns: 1fr auto;
  place-items: center;
  justify-items: flex-end;
  gap: 1rem;
  margin-block-start: 3rem;
}

@media (height <= 640px) {
  form {
    grid-auto-flow: column;
    gap: .25rem;
  }
  
  form > label:last-of-type {
    margin-inline-start: 2rem;
  }
}
!

JS 

              
                document.body.setAttribute('dir', 'ltr')

window.show_scrollbars.addEventListener('input', e =>
  window.box_model.setAttribute('scrollbars', e.target.checked))

window.inline_scrollbars.addEventListener('input', e =>
  window.box_model.setAttribute('inline-scrollbars', e.target.checked))
!
999px

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