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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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About the <head>

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Insecure Resource

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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 

              
                <svg xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink" id="symbols">
  
    <symbol id="symbol-test-1" viewBox="0 0 325 90" preserveAspectRatio="none">
      <polygon points="325 45
                       288 90
                       0 90
                       0 0
                       288 0"/>
    </symbol>
  
  <!--

  1. Beginning with base polygon shape, add an even stroke width with rounded joins.
  2. Divide even stroke number by 2. So a stroke of 20 / 2 = 10
  3. Add halved stroke number to both X and Y of viewBox coordinates.
  4. Change all instances of 0 to halved stroke number.
  5. Quarter stroke number and add this value to Y coordinate of middle point.

  It's actually not necessary to use an even stroke, because we can use decimals.
  It just makes the math easier and more intuitive.

  To test that coordinates were properly shifted, set item margin-bottom to 1px.
  They should be flush with 1px gap.

  -->
  
  <symbol id="symbol-test-2" viewBox="0 0 335 100" preserveAspectRatio="none">
    <polygon points="325 50
                     288 90
                     10 90
                     10 10
                     288 10" 
             stroke-linejoin="round"
             stroke-width="20"/>
  </symbol>
  
  <symbol id="symbol-test-3" viewBox="0 0 333 98" preserveAspectRatio="none">
    <polygon points="325 49
                     288 90
                     8 90
                     8 8
                     288 8" 
             stroke-linejoin="round"
             stroke-width="16"/>
    </symbol>
  
    <symbol id="symbol-test-4" viewBox="0 0 332 97" preserveAspectRatio="none">
      <polygon points="325 48.5
                       288 90
                       7 90
                       7 7
                       288 7"
               stroke-linejoin="round"
               stroke-width="14"/>
    </symbol>
  
    <symbol id="symbol-test-5" viewBox="0 0 332 97" preserveAspectRatio="none">
        <polygon points="325 48.5 
                         288 90 
                         7 90 
                         7 7 
                         288 7"
                 fill="black" 
                 stroke="black" 
                 stroke-linejoin="round" 
                 stroke-width="14"/>
      </symbol>
  
</svg>

<div id="test-1" class="item">
  Mr. and Mrs. Dursley, of number four, Privet Drive, were proud to say that they were perfectly normal, thank you very much.
  <svg>
    <use xlink:href="#symbol-test-4"></use>
  </svg>
</div>

<div id="test-2" class="item">
  They were the last people you'd expect to be involved in anything strange or mysterious, because they just didn't hold with such nonsense.
  <svg>
    <use xlink:href="#symbol-test-4"></use>
  </svg>
</div>

<div id="test-3" class="item">
  Chapter 1
  <svg>
    <use xlink:href="#symbol-test-4"></use>
  </svg>
</div>

<div id="test-4" class="item item-2">
  They were the last people you'd expect to be involved in anything strange or mysterious, because they just didn't hold with such nonsense.
</div>
!

CSS 

              
                @color: #FFF;

.item
{
  // transition: all 300ms linear;
  
  display: flex;
  box-sizing: border-box;
  color: hsv(0, 0, 30%);
  flex-flow: column wrap;
  justify-content: center;
  margin-bottom: 10px;
  min-height: 90px;
  padding: 20px 45px 20px 20px;
  position: relative;
    top: 0;
    left: 0;
  width: 325px;
  
  &:hover
  {
    // There does appear to be some "stickiness"
    // on this transform, especially if hovering
    // quickly between the items. Doesn't happen
    // if transition only exists on hover.
    // Possibly due to referencing same symbol?
    transform: translateX(20px);
    transition: all 300ms linear;
  }
  
  svg
  {
    display: block;
    fill: @color;
    height: 100%;
    opacity: 0.75;
    position: absolute;
      top: 0;
      right: 0;
      z-index: -1;
    stroke: @color;
    width: 100%;
  }
}

// Why doesn't this work in Firefox? :(
// Sensitive to how SVG mark-up is crafted? That does seem to be where I'm having problems.
// Otherwise if it can work between browsers, this is a great solution.
// Major pro: can use CSS properties instead of SVG filters, which are far less
// intuitive to work with and change.
.item-2
{
  background-color: rgba(255, 255, 255, 0.50);
  box-shadow: inset 1px 1px 4px rgba(0, 0, 0, 0.10);
  mask: url('data:image/svg+xml;base64,PHN2ZyB4bWxucz0iaHR0cDovL3d3dy53My5vcmcvMjAwMC9zdmciIHhtbG5zOnhsaW5rPSJodHRwOi8vd3d3LnczLm9yZy8xOTk5L3hsaW5rIiB2aWV3Qm94PSIwIDAgMzMyIDk3IiBwcmVzZXJ2ZUFzcGVjdFJhdGlvPSJub25lIj48cG9seWdvbiBwb2ludHM9IjMyNSA0OC41IDI4OCA5MCA3IDkwIDcgNyAyODggNyIgZmlsbD0iYmxhY2siIHN0cm9rZT0iYmxhY2siIHN0cm9rZS1saW5lam9pbj0icm91bmQiIHN0cm9rZS13aWR0aD0iMTQiLz4KPC9zdmc+') no-repeat 50% 50%;
}

body
{
  background: hsv(0, 0, 93%);
  margin: 1.000em;
}

#symbols
{
  display: none;
}
!

JS
!
999px

Console