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HTML 

              
                <body>

  <h1>Code highlighting with Prism.js</h1>
  
  <p>A pen to highlight embedded code examples using Prism.js with a dark or light mode theme.</p>

  <p>Reference the CSS and JavaScript of this pen, as external resources, to highlight code samples in other pens or projects. Alternatively, copy the <a href="#minified">Minified CSS &amp; JS</a> into your own pages.</p>

  <p>Supports light and dark mode switching via the OS setting, or <a target=_blank title="[new window]" href="https://codepen.io/2kool2/pen/abzgPzJ">Light &amp; dark mode, with user-switch button</a> which, if used, would require importing separately.</p>
    <p>Only <code class="language-css">pre[class*="language-"]{}</code> and <code class=language-css>code[class*="language-"]{}</code> are stylised where:</p>

  <ul>
    <li><code class=language-html>&lt;code class=language-html&gt;</code> &ndash; HTML (or XML)</li>
    <li><code class=language-html>&lt;code class=language-css&gt;</code> &ndash; CSS</li>
    <li><code class=language-html>&lt;code class=language-js&gt;</code> &ndash; JavaScript</li>
    <li><code class=language-html>&lt;code class=language-clike&gt;</code> &ndash; PHP</li>
  </ul>
  
  <h2>The HTML code</h2>

<figure>
  <figcaption>HTML <small>(semantic layout for a code block)</small></figcaption>
  <pre><code class=language-html spellcheck=false contenteditable>&lt;figure&gt;
  &lt;figcaption&gt;Code title&lt;/figcaption&gt;
  &lt;pre&gt;&lt;code class=language-html contenteditable spellcheck=false&gt;
  &hellip; Code example here (Escaped HTML symbols/entities) &hellip;
  &lt;/code&gt;&lt;/pre&gt;
&lt;/figure&gt;</code></pre>
</figure>
  
<p>Ensure the code example has its HTML symbols escaped. That is, as a minimum, replace:</p>
<ul>
  <li>&nbsp; &lt;&nbsp; with&nbsp; &amp;lt;</li>
  <li>&nbsp; &gt;&nbsp; with&nbsp; &amp;gt;</li>
  <li>&nbsp; &amp;&nbsp; with&nbsp; &amp;amp;</li>
</ul>
<p>To simplify the process I use the online tool: <a target=_blank title="[new window]" href="https://websemantics.uk/tools/escaping-html/">Escaping HTML symbols/entities</a></p>

<p>Both the <code class=language-html>&lt;figure&gt;</code> and <code class=language-html>&lt;figcaption&gt;</code> elements are unopinionated when importing the CSS from this pen.</p>

<p>The <code class=language-html>contenteditable</code> attribute makes the code block extremely keyboard friendly. Very usefully allowing:</p>
  <ul>
    <li>Arrow key navigation</li>
    <li>Word, or line, selection (double, or triple, tap or click)</li>
    <li>Jump to the end, or start, of a line or block, (cmd arrows)</li>
    <li>Select all (cmd a, or ctrl a on a PC)</li>
    <li>Copy (cmd c, or ctrl c on a PC)</li>
    <li>Even allows custom editing prior to copying.</li>
  </ul>
  
  <style>

/* Page styles here so the CSS is unpolluted for use in other pens */

h2 {
  font-weight: 100;
}

/* Grid spacing */
[class^="grid_parent"] {
  --spacing: 1rem;
  --bgGridItem: hsla(214, 100%, 90%, 0.1);
  --borderGridItem: #ccc;
  margin: 0;
}
@media (min-width: 48em) { /* 768px */
  [class^="grid_parent"] {
    --spacing: 1rem;
  }
}
[data-lightMode="dark"] [class^="grid_parent"] {
  --bgGridItem: hsla(214, 0%, 0%, 0.2);
  --borderGridItem: #333;
}

/* The grid */
[class^="grid-"] {
  --columns: 1;
  display: grid;
  grid-gap: var(--spacing);
  grid-template-columns: var(--columns);
}
@media (min-width: 40em) { /* 640px */
  [class^="grid-2"] {
    --columns: 1fr 1fr;
  }
}
@media (min-width: 60em) { /* 960px */
  [class^="grid-3"],
  [class^="grid-2_3"] {
    --columns: 1fr 1fr 1fr;
  }
}
@media (min-width: 80em) { /* 1280px */
  [class^="grid-2_4"],
  [class^="grid-2_3_4"] {
    --columns: 1fr 1fr 1fr 1fr;
  }
}
@media (min-width: 120em) { /* 1920px */
  [class^="grid-2_3_6"],
  [class^="grid-2_3_4_6"] {
    --columns: 1fr 1fr 1fr 1fr 1fr 1fr;
  }
}

/* Grid item */
[class^="grid_item"] {
  /* Required, but may be changed */
  min-width: calc(20rem - var(--spacing) * 3 - 2px);
  padding: calc(var(--spacing) / 2);
  margin: 0;
}


/* Jus' colourin' */
[class^="grid_item"] {
  border: 1px solid var(--borderGridItem);
  background-color: var(--bgGridItem);
  transition:
    border-color .3s ease-out,
    background-color .3s ease-out;
}
  </style>

  <section class=grid_parent>
    <h2>Test cases</h2>

    <div class=grid-2_3>

      <figure class=grid_item>
        <figcaption>code <small>(unopinionated)</small></figcaption>
        <code>p { color: red; }</code>
      </figure>

      <figure class=grid_item>
        <figcaption>pre &gt; code <small>(unopinionated)</small></figcaption>
        <pre><code>p { color: red; }</code></pre>
      </figure>

      <figure class=grid_item>
        <figcaption>code.language-css <small>(inline use)</small></figcaption>
        <code class=language-css>p { color: red; }</code>
      </figure>

      <figure class=grid_item>
        <figcaption>pre.language-css &gt; code</figcaption>
        <pre class=language-css><code>p { color: red; }</code></pre>
      </figure>

      <figure class=grid_item>
        <figcaption>pre &gt; code.language-css</figcaption>
        <pre><code class=language-css>p { color: red; }</code></pre>
      </figure>

      <figure class=grid_item>
        <figcaption>pre &gt; code.language-css[contenteditable] <small>(recommended)</small></figcaption>
        <pre><code class=language-css spellcheck=false contenteditable>p { color: red; }</code></pre>
      </figure>

    </div>
    
    </section>
  
  <h2>The stylesheet</h2>

<figure>
  <figcaption>Common CSS for both modes <small>(generated at <a href="http://prismjs.com/">prismjs.com</a> then extended)</small></figcaption>
  <pre><code class=language-css contenteditable spellcheck=false>[class*="language-"] ::selection {
  color: #000;
  background: hsl(214, 100%, 85%);
  text-shadow: none;
}

pre[class*="language-"] {
  overflow: auto;
  margin: 0;
  background-color: transparent;
  
  /* Allow space for an overflow ellipsis */
  padding-right: 0.5rem;
  
  /* Allow space for SVG "tear off strip" */
  background-origin: border-box;
  border-left: 2.5rem solid transparent;
  background-size: 120rem 4rem;
  /* Single line does not sit on stripes */
  background-position: top -1.2rem left 0;
  
  /* Allow horizontal resizing - could be adjusted to allow vertical resizing too */
  position: relative;
  resize: horizontal;
  min-width: calc(100% - 3rem);
  
  transition: box-shadow .3s ease-out;
}

code[class*="language-"] {
  font-family: monospace, monospace;
  letter-spacing: 0.01em;
  text-align: left;
  white-space: pre;
  word-spacing: normal;
  word-break: normal;
  word-wrap: normal;
  line-height: 2;
  tab-size: 2;
  hyphens: none;
}

pre &gt; code[class*="language-"],
pre[class*="language-"] &gt; code {
  display: block;
  padding: 0.75rem 0;

  /* Use an ellipsis to indicate code is wider than the display area */
  text-overflow: ellipsis;
  overflow-x: scroll;
}
pre:hover &gt; code[class*="language-"],
pre:focus-within &gt; code[class*="language-"] {
  outline: none;
  text-overflow: inherit;
}

/* Inline code only */
:not(pre) &gt; code[class*="language-"] {
  font-size: inherit;
  background-position: top right;
  background-size: auto 4rem;
  padding: 0.125em 0.25em;
  white-space: normal;
  word-wrap: nowrap;
}

.token.important,
.token.bold {
  font-weight: bold;
}
.token.italic {
  font-style: italic;
}
.token.entity {
  cursor: help;
}
.namespace {
  opacity: 0.7;
}</code></pre>
</figure>


  <h2>Colours used</h2>

  <p>Custom properties (CSS variables) are extensively used to define the highlight colours and the background image.</p>
  <p>Colour contrast, in both modes, has been checked against WCAG 2 guidelines using <a target=_blank title="[new window]" href="https://websemantics.uk/tools/wcag-colour-contrast-checker/">WCAG colour contrast checker</a> and pass, at the least, to AA.</p>
  <p>The design allows text zoom to 200%, and beyond, scaling the background accordingly and fully meeting WCAG requirements.</p>


<figure>
  <figcaption>CSS default colours <small>(light-mode)</small></figcaption>
  <pre><code class=language-css contenteditable spellcheck=false>:not(pre) &gt; code[class*="language-"],
pre[class*="language-"] {
  --color: #000;
  --textShadow: #fff;
  --comment: #6e6e6e;
  --punctuation: #4e4e4e;
  --property: #905;
  --operator: #70b;
  --selector: #487b00;
  --url: #8d6640;
  --urlBg: hsla(0, 0%, 100%, .5);
  --boolean: #905;
  --atrule: #0075a8;
  --keyword: #0075a8;
  --function: #c93654;
  --regex: #860;
  --boxShadow: hsla(0,0%,0%,.3);
  --focusOutline: hsla(214, 100%, 85%, 1);
  --codeBgImg: url("data:image/svg+xml;charset=utf8,%3Csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 1920 64'%3E%3Ccircle stroke='rgba(0,64,0,.3)' stroke-width='2' fill='none' cx='20' cy='49' r='12'/%3E%3Cpath fill='%23fcfcfa' fill-rule='evenodd' d='M1920 64H0V0h1920v64zM20 36a11 11 0 110 22 11 11 0 010-22z'/%3E%3Cpath stroke='%23edf3ed' stroke-width='2' d='M0 1h1920M0 5h1920M0 9h1920M0 13h1920M0 17h1920M0 21h1920M0 25h1920M0 29h1920'/%3E%3Cpath stroke='%23e4ede4' stroke-dasharray='2 6 2 6' stroke-width='2' d='M40 2v60'/%3E%3C/svg%3E");
}</code></pre>
</figure>


<figure>
  <figcaption>CSS dark-mode colours <small>(media query)</small></figcaption>
  <pre><code class=language-css contenteditable spellcheck=false>@media (prefers-color-scheme: dark) {
  body:not([data-lightMode="light"]) code[class*="language-"]:not([contenteditable]),
  body:not([data-lightMode="light"]) pre[class*="language-"] {
    --color: #6ae;
    --textShadow: #000;
    --comment: #9ab;
    --punctuation: #ccc;
    --property: #e60;
    --operator: #d7f;
    --selector: #8b2;
    --url: #cde;
    --urlBg: rgba(0,0,0,.5);
    --boolean: #a8f;
    --atrule: #ffb;
    --keyword: #f55;
    --function: #fe6;
    --regex: #f91;
    --boxShadow: #000;
    --focusOutline: hsla(214, 100%, 85%, .6);
    --codeBgImg: url("data:image/svg+xml;charset=utf8,%3Csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 1920 64'%3E%3Ccircle stroke='rgba(0,0,0,.7)' stroke-width='2' fill='none' cx='20' cy='49' r='12'/%3E%3Cpath fill='%23101610' fill-rule='evenodd' d='M1920 64H0V0h1920v64zM20 36a11 11 0 110 22 11 11 0 010-22z'/%3E%3Cpath stroke='%23121' stroke-width='2' d='M0 1h1920M0 5h1920M0 9h1920M0 13h1920M0 17h1920M0 21h1920M0 25h1920M0 29h1920'/%3E%3Cpath stroke='%23121' stroke-dasharray='2 6 2 6' stroke-width='2' d='M40 2v60'/%3E%3C/svg%3E");
  }
}</code></pre>
</figure>


<figure>
  <figcaption>CSS dark-mode colours <small>(manual switch mode)</small></figcaption>
  <pre><code class=language-css contenteditable spellcheck=false>body[data-lightMode="dark"] code[class*="language-"]:not([contenteditable]),
body[data-lightMode="dark"] pre[class*="language-"] {

  /* Exactly the same as prefers-color-scheme: dark */
  --color: #6ae;
  --textShadow: #000;
  --comment: #9ab;
  --punctuation: #ccc;
  --property: #e60;
  --operator: #d7f;
  --selector: #8b2;
  --url: #cde;
  --urlBg: rgba(0,0,0,.5);
  --boolean: #8af;
  --atrule: #ffb;
  --keyword: #f55;
  --function: #fe6;
  --regex: #f91;
  --boxShadow: #000;
  --focusOutline: hsla(214, 100%, 85%, .6);
  --codeBgImg: url("data:image/svg+xml;charset=utf8,%3Csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 1920 64'%3E%3Ccircle stroke='rgba(0,0,0,.7)' stroke-width='2' fill='none' cx='20' cy='49' r='12'/%3E%3Cpath fill='%23101610' fill-rule='evenodd' d='M1920 64H0V0h1920v64zM20 36a11 11 0 110 22 11 11 0 010-22z'/%3E%3Cpath stroke='%23121' stroke-width='2' d='M0 1h1920M0 5h1920M0 9h1920M0 13h1920M0 17h1920M0 21h1920M0 25h1920M0 29h1920'/%3E%3Cpath stroke='%23121' stroke-dasharray='2 6 2 6' stroke-width='2' d='M40 2v60'/%3E%3C/svg%3E");
}</code></pre>
</figure>


<figure>
  <figcaption>CSS colour variable styles</figcaption>
  <pre><code class=language-css contenteditable spellcheck=false>code[class*="language-"],
pre[class*="language-"] {
  color: var(--color);
  text-shadow: 0 1px var(--textShadow);
}

/* Background image is applied to the pre element on blocks, mainly because it is cropped when applied to the code element. */
:not(pre) &gt; code[class*="language-"],
pre[class*="language-"] {
  background-image: var(--codeBgImg);
}
pre[class*="language-"]:hover,
pre[class*="language-"]:focus-within {
  box-shadow: 0 .25rem .25rem var(--boxShadow);
}
pre[class*="language-"]:focus-within {
  outline-offset: calc(-0.25rem - 1px);
  outline: var(--focusOutline) solid 0.25rem;
  z-index: 5;
}

.token.comment,
.token.prolog,
.token.doctype,
.token.cdata {
  color: var(--comment);
}
.token.punctuation {
  color: var(--punctuation);
}
.token.property,
.token.symbol,
.token.tag,
.token.constant,
.token.deleted {
  color: var(--property);
}
.token.boolean,
.token.number {
  color: var(--boolean);
}
.token.selector,
.token.attr-name,
.token.string,
.token.char,
.token.builtin,
.token.inserted {
  color: var(--selector);
}
.token.operator {
  color: var(--operator);
}
.token.url,
.token.entity,
.language-css .token.string,
.style .token.string {
  color: var(--url);
  background-color: var(--urlBg);
}
.token.atrule,
.token.attr-value {
  color: var(--atrule);
}
.token.keyword {
  color: var(--keyword);
}
.token.function {
  color: var(--function);
}
.token.regex,
.token.important,
.token.variable {
  color: var(--regex);
}</code></pre>
</figure>


<h2>Miscellaneous</h2>


<figure>
  <figcaption>Print styles</figcaption>
  <pre><code class=language-css contenteditable spellcheck=false>@media print {
  code[class*="language-"],
  pre[class*="language-"] {
    text-shadow: none;
  }
}</code></pre>
</figure>


<figure>
  <figcaption>Code paper SVG <small>(light-mode)</small></figcaption>
  <pre class=pre-oneLine><code class=language-html contenteditable spellcheck=false>&lt;svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 1920 64"&gt;
  &lt;circle stroke="rgba(0,64,0,.3)" stroke-width="2" fill="none" cx="20" cy="49" r="12"/&gt;
  &lt;path fill="#fcfcfa" fill-rule="evenodd" d="M1920 64H0V0h1920v64zM20 36a11 11 0 110 22 11 11 0 010-22z"/&gt;
  &lt;path stroke="#edf3ed" stroke-width="2" d="M0 1h1920M0 5h1920M0 9h1920M0 13h1920M0 17h1920M0 21h1920M0 25h1920M0 29h1920"/&gt;
  &lt;path stroke="#e4ede4" stroke-dasharray="2 6 2 6" stroke-width="2" d="M40 2v60"/&gt;
&lt;/svg&gt;
</code></pre>
</figure>


<figure>
  <figcaption>Code paper SVG <small>(dark-mode)</small></figcaption>
  <pre class=pre-oneLine><code class=language-html contenteditable spellcheck=false>&lt;svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 1920 64"&gt;
  &lt;circle stroke="rgba(0,0,0,.7)" stroke-width="2" fill="none" cx="20" cy="49" r="12"/&gt;
  &lt;path fill="#101610" fill-rule="evenodd" d="M1920 64H0V0h1920v64zM20 36a11 11 0 110 22 11 11 0 010-22z"/&gt;
  &lt;path stroke="#121" stroke-width="2" d="M0 1h1920M0 5h1920M0 9h1920M0 13h1920M0 17h1920M0 21h1920M0 25h1920M0 29h1920"/&gt;
  &lt;path stroke="#131" stroke-dasharray="2 6 2 6" stroke-width="2" d="M40 2v60"/&gt;
&lt;/svg&gt;</code></pre>
</figure>

  <p>The SVG was converted into a CSS background using: <a target=_blank title="[new window]" href="https://websemantics.uk/tools/svg-to-background-image-conversion/">SVG to CSS background-image converter</a>. I did investigate using CSS variables here. Unfortunately, CSS vars do not work inside a background-image. Besides, it does allow for a different image in each mode.</p>



<h2 id=minified>Minified CSS &amp; JavaScript</h2>




<figure>
  <figcaption>All CSS <small>[5.10 KB, Gzip: 1.53 KB]</small></figcaption>
  <pre class=pre-oneLine><code class=language-css contenteditable spellcheck=false>[class*="language-"] ::selection{color:#000;background:#b2d3ff;text-shadow:none}pre[class*=language-]{overflow:auto;margin:0;background-color:transparent;padding-right:.5rem;background-origin:border-box;border-left:2.5rem solid transparent;background-size:120rem 4rem;background-position:top -1.2rem left 0;position:relative;resize:horizontal;min-width:calc(100% - 3rem);transition:box-shadow .3s ease-out}code[class*=language-]{font-family:monospace,monospace;letter-spacing:.01em;text-align:left;white-space:pre;word-spacing:normal;word-break:normal;word-wrap:normal;line-height:2;tab-size:2;hyphens:none}pre>code[class*=language-],pre[class*=language-]>code{display:block;padding:.75rem 0;text-overflow:ellipsis;overflow-x:scroll}pre:focus-within>code[class*=language-],pre:hover>code[class*=language-]{outline:0;text-overflow:inherit}:not(pre)>code[class*=language-]{font-size:inherit;background-position:top right;background-size:auto 4rem;padding:.125em .25em;white-space:normal;word-wrap:nowrap}.token.bold,.token.important{font-weight:700}.token.italic{font-style:italic}.token.entity{cursor:help}.namespace{opacity:.7}:not(pre)>code[class*=language-],pre[class*=language-]{--color:#000;--textShadow:#fff;--comment:#7a7a7a;--punctuation:#6e6e6e;--property:#905;--operator:#70b;--selector:#487b00;--url:#8d6640;--urlBg:hsla(0, 0%, 100%, .5);--boolean:#905;--atrule:#0075a8;--keyword:#0075a8;--function:#c93654;--regex:#860;--boxShadow:hsla(0,0%,0%,.3);--focusOutline:hsla(214, 100%, 85%, 1);--codeBgImg:url("data:image/svg+xml;charset=utf8,%3Csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 1920 64'%3E%3Ccircle stroke='rgba(0,64,0,.3)' stroke-width='2' fill='none' cx='20' cy='49' r='12'/%3E%3Cpath fill='%23fcfcfa' fill-rule='evenodd' d='M1920 64H0V0h1920v64zM20 36a11 11 0 110 22 11 11 0 010-22z'/%3E%3Cpath stroke='%23edf3ed' stroke-width='2' d='M0 1h1920M0 5h1920M0 9h1920M0 13h1920M0 17h1920M0 21h1920M0 25h1920M0 29h1920'/%3E%3Cpath stroke='%23e4ede4' stroke-dasharray='2 6 2 6' stroke-width='2' d='M40 2v60'/%3E%3C/svg%3E");background-image:var(--codeBgImg)}@media (prefers-color-scheme:dark){body:not([data-lightMode=light]) code[class*=language-]:not([contenteditable]),body:not([data-lightMode=light]) pre[class*=language-]{--color:#6ae;--textShadow:#000;--comment:#9ab;--punctuation:#ccc;--property:#e60;--operator:#d7f;--selector:#8b2;--url:#cde;--urlBg:rgba(0,0,0,.5);--boolean:#a8f;--atrule:#ffb;--keyword:#f55;--function:#fe6;--regex:#f91;--boxShadow:#000;--focusOutline:hsla(214, 100%, 85%, .6);--codeBgImg:url("data:image/svg+xml;charset=utf8,%3Csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 1920 64'%3E%3Ccircle stroke='rgba(0,0,0,.7)' stroke-width='2' fill='none' cx='20' cy='49' r='12'/%3E%3Cpath fill='%23101610' fill-rule='evenodd' d='M1920 64H0V0h1920v64zM20 36a11 11 0 110 22 11 11 0 010-22z'/%3E%3Cpath stroke='%23121' stroke-width='2' d='M0 1h1920M0 5h1920M0 9h1920M0 13h1920M0 17h1920M0 21h1920M0 25h1920M0 29h1920'/%3E%3Cpath stroke='%23121' stroke-dasharray='2 6 2 6' stroke-width='2' d='M40 2v60'/%3E%3C/svg%3E")}}body[data-lightMode=dark] code[class*=language-]:not([contenteditable]),body[data-lightMode=dark] pre[class*=language-]{--color:#6ae;--textShadow:#000;--comment:#9ab;--punctuation:#ccc;--property:#e60;--operator:#d7f;--selector:#8b2;--url:#cde;--urlBg:rgba(0,0,0,.5);--boolean:#8af;--atrule:#ffb;--keyword:#f55;--function:#fe6;--regex:#f91;--boxShadow:#000;--focusOutline:hsla(214, 100%, 85%, .6);--codeBgImg:url("data:image/svg+xml;charset=utf8,%3Csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 1920 64'%3E%3Ccircle stroke='rgba(0,0,0,.7)' stroke-width='2' fill='none' cx='20' cy='49' r='12'/%3E%3Cpath fill='%23101610' fill-rule='evenodd' d='M1920 64H0V0h1920v64zM20 36a11 11 0 110 22 11 11 0 010-22z'/%3E%3Cpath stroke='%23121' stroke-width='2' d='M0 1h1920M0 5h1920M0 9h1920M0 13h1920M0 17h1920M0 21h1920M0 25h1920M0 29h1920'/%3E%3Cpath stroke='%23131' stroke-dasharray='2 6 2 6' stroke-width='2' d='M40 2v60'/%3E%3C/svg%3E")}code[class*=language-],pre[class*=language-]{color:var(--color);text-shadow:0 1px var(--textShadow)}pre[class*=language-]:focus-within,pre[class*=language-]:hover{box-shadow:0 .25rem .25rem var(--boxShadow)}pre[class*=language-]:focus-within{outline-offset:calc(-.25rem - 1px);outline:solid var(--focusOutline);z-index:5}.token.cdata,.token.comment,.token.doctype,.token.prolog{color:var(--comment)}.token.punctuation{color:var(--punctuation)}.token.constant,.token.deleted,.token.property,.token.symbol,.token.tag{color:var(--property)}.token.boolean,.token.number{color:var(--boolean)}.token.attr-name,.token.builtin,.token.char,.token.inserted,.token.selector,.token.string{color:var(--selector)}.token.operator{color:var(--operator)}.language-css .token.string,.style .token.string,.token.entity,.token.url{color:var(--url);background-color:var(--urlBg)}.token.atrule,.token.attr-value{color:var(--atrule)}.token.keyword{color:var(--keyword)}.token.function{color:var(--function)}.token.important,.token.regex,.token.variable{color:var(--regex)}@media print{code[class*=language-],pre[class*=language-]{text-shadow:none}}</code></pre>
</figure>


<figure>
  <figcaption>JavaScript <small>[6.77 KB] (built at <a href="https://prismjs.com/">prismjs.com</a>)</small></figcaption>
  <pre><code class=language-js contenteditable spellcheck=false>/* http://prismjs.com/download.html?themes=prism&languages=markup+css+clike+javascript */
var _self="undefined"!=typeof window?window:"undefined"!=typeof WorkerGlobalScope&&self instanceof WorkerGlobalScope?self:{},Prism=function(){var e=/\blang(?:uage)?-(\w+)\b/i,t=0,n=_self.Prism={manual:_self.Prism&&_self.Prism.manual,util:{encode:function(e){return e instanceof a?new a(e.type,n.util.encode(e.content),e.alias):"Array"===n.util.type(e)?e.map(n.util.encode):e.replace(/&/g,"&amp;").replace(/</g,"&lt;").replace(/\u00a0/g," ")},type:function(e){return Object.prototype.toString.call(e).match(/\[object (\w+)\]/)[1]},objId:function(e){return e.__id||Object.defineProperty(e,"__id",{value:++t}),e.__id},clone:function(e){var t=n.util.type(e);switch(t){case"Object":var a={};for(var r in e)e.hasOwnProperty(r)&&(a[r]=n.util.clone(e[r]));return a;case"Array":return e.map&&e.map(function(e){return n.util.clone(e)})}return e}},languages:{extend:function(e,t){var a=n.util.clone(n.languages[e]);for(var r in t)a[r]=t[r];return a},insertBefore:function(e,t,a,r){r=r||n.languages;var i=r[e];if(2==arguments.length){a=arguments[1];for(var l in a)a.hasOwnProperty(l)&&(i[l]=a[l]);return i}var o={};for(var s in i)if(i.hasOwnProperty(s)){if(s==t)for(var l in a)a.hasOwnProperty(l)&&(o[l]=a[l]);o[s]=i[s]}return n.languages.DFS(n.languages,function(t,n){n===r[e]&&t!=e&&(this[t]=o)}),r[e]=o},DFS:function(e,t,a,r){r=r||{};for(var i in e)e.hasOwnProperty(i)&&(t.call(e,i,e[i],a||i),"Object"!==n.util.type(e[i])||r[n.util.objId(e[i])]?"Array"!==n.util.type(e[i])||r[n.util.objId(e[i])]||(r[n.util.objId(e[i])]=!0,n.languages.DFS(e[i],t,i,r)):(r[n.util.objId(e[i])]=!0,n.languages.DFS(e[i],t,null,r)))}},plugins:{},highlightAll:function(e,t){var a={callback:t,selector:'code[class*="language-"], [class*="language-"] code, code[class*="lang-"], [class*="lang-"] code'};n.hooks.run("before-highlightall",a);for(var r,i=a.elements||document.querySelectorAll(a.selector),l=0;r=i[l++];)n.highlightElement(r,e===!0,a.callback)},highlightElement:function(t,a,r){for(var i,l,o=t;o&&!e.test(o.className);)o=o.parentNode;o&&(i=(o.className.match(e)||[,""])[1].toLowerCase(),l=n.languages[i]),t.className=t.className.replace(e,"").replace(/\s+/g," ")+" language-"+i,o=t.parentNode,/pre/i.test(o.nodeName)&&(o.className=o.className.replace(e,"").replace(/\s+/g," ")+" language-"+i);var s=t.textContent,u={element:t,language:i,grammar:l,code:s};if(n.hooks.run("before-sanity-check",u),!u.code||!u.grammar)return u.code&&(n.hooks.run("before-highlight",u),u.element.textContent=u.code,n.hooks.run("after-highlight",u)),n.hooks.run("complete",u),void 0;if(n.hooks.run("before-highlight",u),a&&_self.Worker){var g=new Worker(n.filename);g.onmessage=function(e){u.highlightedCode=e.data,n.hooks.run("before-insert",u),u.element.innerHTML=u.highlightedCode,r&&r.call(u.element),n.hooks.run("after-highlight",u),n.hooks.run("complete",u)},g.postMessage(JSON.stringify({language:u.language,code:u.code,immediateClose:!0}))}else u.highlightedCode=n.highlight(u.code,u.grammar,u.language),n.hooks.run("before-insert",u),u.element.innerHTML=u.highlightedCode,r&&r.call(t),n.hooks.run("after-highlight",u),n.hooks.run("complete",u)},highlight:function(e,t,r){var i=n.tokenize(e,t);return a.stringify(n.util.encode(i),r)},matchGrammar:function(e,t,a,r,i,l,o){var s=n.Token;for(var u in a)if(a.hasOwnProperty(u)&&a[u]){if(u==o)return;var g=a[u];g="Array"===n.util.type(g)?g:[g];for(var c=0;c<g.length;++c){var h=g[c],f=h.inside,d=!!h.lookbehind,m=!!h.greedy,p=0,y=h.alias;if(m&&!h.pattern.global){var v=h.pattern.toString().match(/[imuy]*$/)[0];h.pattern=RegExp(h.pattern.source,v+"g")}h=h.pattern||h;for(var b=r,k=i;b<t.length;k+=t[b].length,++b){var w=t[b];if(t.length>e.length)return;if(!(w instanceof s)){h.lastIndex=0;var _=h.exec(w),P=1;if(!_&&m&&b!=t.length-1){if(h.lastIndex=k,_=h.exec(e),!_)break;for(var A=_.index+(d?_[1].length:0),j=_.index+_[0].length,x=b,O=k,S=t.length;S>x&&(j>O||!t[x].type&&!t[x-1].greedy);++x)O+=t[x].length,A>=O&&(++b,k=O);if(t[b]instanceof s||t[x-1].greedy)continue;P=x-b,w=e.slice(k,O),_.index-=k}if(_){d&&(p=_[1].length);var A=_.index+p,_=_[0].slice(p),j=A+_.length,N=w.slice(0,A),C=w.slice(j),E=[b,P];N&&(++b,k+=N.length,E.push(N));var L=new s(u,f?n.tokenize(_,f):_,y,_,m);if(E.push(L),C&&E.push(C),Array.prototype.splice.apply(t,E),1!=P&&n.matchGrammar(e,t,a,b,k,!0,u),l)break}else if(l)break}}}}},tokenize:function(e,t){var a=[e],r=t.rest;if(r){for(var i in r)t[i]=r[i];delete t.rest}return n.matchGrammar(e,a,t,0,0,!1),a},hooks:{all:{},add:function(e,t){var a=n.hooks.all;a[e]=a[e]||[],a[e].push(t)},run:function(e,t){var a=n.hooks.all[e];if(a&&a.length)for(var r,i=0;r=a[i++];)r(t)}}},a=n.Token=function(e,t,n,a,r){this.type=e,this.content=t,this.alias=n,this.length=0|(a||"").length,this.greedy=!!r};if(a.stringify=function(e,t,r){if("string"==typeof e)return e;if("Array"===n.util.type(e))return e.map(function(n){return a.stringify(n,t,e)}).join("");var i={type:e.type,content:a.stringify(e.content,t,r),tag:"span",classes:["token",e.type],attributes:{},language:t,parent:r};if("comment"==i.type&&(i.attributes.spellcheck="true"),e.alias){var l="Array"===n.util.type(e.alias)?e.alias:[e.alias];Array.prototype.push.apply(i.classes,l)}n.hooks.run("wrap",i);var o=Object.keys(i.attributes).map(function(e){return e+'="'+(i.attributes[e]||"").replace(/"/g,"&quot;")+'"'}).join(" ");return"<"+i.tag+' class="'+i.classes.join(" ")+'"'+(o?" "+o:"")+">"+i.content+"</"+i.tag+">"},!_self.document)return _self.addEventListener?(_self.addEventListener("message",function(e){var t=JSON.parse(e.data),a=t.language,r=t.code,i=t.immediateClose;_self.postMessage(n.highlight(r,n.languages[a],a)),i&&_self.close()},!1),_self.Prism):_self.Prism;var r=document.currentScript||[].slice.call(document.getElementsByTagName("script")).pop();return r&&(n.filename=r.src,!document.addEventListener||n.manual||r.hasAttribute("data-manual")||("loading"!==document.readyState?window.requestAnimationFrame?window.requestAnimationFrame(n.highlightAll):window.setTimeout(n.highlightAll,16):document.addEventListener("DOMContentLoaded",n.highlightAll))),_self.Prism}();"undefined"!=typeof module&&module.exports&&(module.exports=Prism),"undefined"!=typeof global&&(global.Prism=Prism);
Prism.languages.markup={comment:/<!--[\s\S]*?-->/,prolog:/<\?[\s\S]+?\?>/,doctype:/<!DOCTYPE[\s\S]+?>/i,cdata:/<!\[CDATA\[[\s\S]*?]]>/i,tag:{pattern:/<\/?(?!\d)[^\s>\/=$<]+(?:\s+[^\s>\/=]+(?:=(?:("|')(?:\\\1|\\?(?!\1)[\s\S])*\1|[^\s'">=]+))?)*\s*\/?>/i,inside:{tag:{pattern:/^<\/?[^\s>\/]+/i,inside:{punctuation:/^<\/?/,namespace:/^[^\s>\/:]+:/}},"attr-value":{pattern:/=(?:('|")[\s\S]*?(\1)|[^\s>]+)/i,inside:{punctuation:/[=>"']/}},punctuation:/\/?>/,"attr-name":{pattern:/[^\s>\/]+/,inside:{namespace:/^[^\s>\/:]+:/}}}},entity:/&#?[\da-z]{1,8};/i},Prism.languages.markup.tag.inside["attr-value"].inside.entity=Prism.languages.markup.entity,Prism.hooks.add("wrap",function(a){"entity"===a.type&&(a.attributes.title=a.content.replace(/&amp;/,"&"))}),Prism.languages.xml=Prism.languages.markup,Prism.languages.html=Prism.languages.markup,Prism.languages.mathml=Prism.languages.markup,Prism.languages.svg=Prism.languages.markup;
Prism.languages.css={comment:/\/\*[\s\S]*?\*\//,atrule:{pattern:/@[\w-]+?.*?(;|(?=\s*\{))/i,inside:{rule:/@[\w-]+/}},url:/url\((?:(["'])(\\(?:\r\n|[\s\S])|(?!\1)[^\\\r\n])*\1|.*?)\)/i,selector:/[^\{\}\s][^\{\};]*?(?=\s*\{)/,string:{pattern:/("|')(\\(?:\r\n|[\s\S])|(?!\1)[^\\\r\n])*\1/,greedy:!0},property:/(\b|\B)[\w-]+(?=\s*:)/i,important:/\B!important\b/i,"function":/[-a-z0-9]+(?=\()/i,punctuation:/[(){};:]/},Prism.languages.css.atrule.inside.rest=Prism.util.clone(Prism.languages.css),Prism.languages.markup&&(Prism.languages.insertBefore("markup","tag",{style:{pattern:/(<style[\s\S]*?>)[\s\S]*?(?=<\/style>)/i,lookbehind:!0,inside:Prism.languages.css,alias:"language-css"}}),Prism.languages.insertBefore("inside","attr-value",{"style-attr":{pattern:/\s*style=("|').*?\1/i,inside:{"attr-name":{pattern:/^\s*style/i,inside:Prism.languages.markup.tag.inside},punctuation:/^\s*=\s*['"]|['"]\s*$/,"attr-value":{pattern:/.+/i,inside:Prism.languages.css}},alias:"language-css"}},Prism.languages.markup.tag));
Prism.languages.clike={comment:[{pattern:/(^|[^\\])\/\*[\s\S]*?\*\//,lookbehind:!0},{pattern:/(^|[^\\:])\/\/.*/,lookbehind:!0}],string:{pattern:/(["'])(\\(?:\r\n|[\s\S])|(?!\1)[^\\\r\n])*\1/,greedy:!0},"class-name":{pattern:/((?:\b(?:class|interface|extends|implements|trait|instanceof|new)\s+)|(?:catch\s+\())[a-z0-9_\.\\]+/i,lookbehind:!0,inside:{punctuation:/(\.|\\)/}},keyword:/\b(if|else|while|do|for|return|in|instanceof|function|new|try|throw|catch|finally|null|break|continue)\b/,"boolean":/\b(true|false)\b/,"function":/[a-z0-9_]+(?=\()/i,number:/\b-?(?:0x[\da-f]+|\d*\.?\d+(?:e[+-]?\d+)?)\b/i,operator:/--?|\+\+?|!=?=?|<=?|>=?|==?=?|&&?|\|\|?|\?|\*|\/|~|\^|%/,punctuation:/[{}[\];(),.:]/};
Prism.languages.javascript=Prism.languages.extend("clike",{keyword:/\b(as|async|await|break|case|catch|class|const|continue|debugger|default|delete|do|else|enum|export|extends|finally|for|from|function|get|if|implements|import|in|instanceof|interface|let|new|null|of|package|private|protected|public|return|set|static|super|switch|this|throw|try|typeof|var|void|while|with|yield)\b/,number:/\b-?(0[xX][\dA-Fa-f]+|0[bB][01]+|0[oO][0-7]+|\d*\.?\d+([Ee][+-]?\d+)?|NaN|Infinity)\b/,"function":/[_$a-zA-Z\xA0-\uFFFF][_$a-zA-Z0-9\xA0-\uFFFF]*(?=\()/i,operator:/-[-=]?|\+[+=]?|!=?=?|<<?=?|>>?>?=?|=(?:==?|>)?|&[&=]?|\|[|=]?|\*\*?=?|\/=?|~|\^=?|%=?|\?|\.{3}/}),Prism.languages.insertBefore("javascript","keyword",{regex:{pattern:/(^|[^\/])\/(?!\/)(\[[^\]\r\n]+]|\\.|[^\/\\\[\r\n])+\/[gimyu]{0,5}(?=\s*($|[\r\n,.;})]))/,lookbehind:!0,greedy:!0}}),Prism.languages.insertBefore("javascript","string",{"template-string":{pattern:/`(?:\\\\|\\?[^\\])*?`/,greedy:!0,inside:{interpolation:{pattern:/\$\{[^}]+\}/,inside:{"interpolation-punctuation":{pattern:/^\$\{|\}$/,alias:"punctuation"},rest:Prism.languages.javascript}},string:/[\s\S]+/}}}),Prism.languages.markup&&Prism.languages.insertBefore("markup","tag",{script:{pattern:/(<script[\s\S]*?>)[\s\S]*?(?=<\/script>)/i,lookbehind:!0,inside:Prism.languages.javascript,alias:"language-javascript"}}),Prism.languages.js=Prism.languages.javascript;</code></pre>
</figure>
  
  
  <h2>References</h2>
  
  <ul>
    <li><a target=_blank title="[new window]" href="https://websemantics.uk/articles/displaying-code-in-web-pages/">Displaying code in a web pages</a></li>
    <li><a target=_blank title="[new window]" href="https://hankchizljaw.com/wrote/create-a-user-controlled-dark-or-light-mode/">Create a user controlled dark or light mode</a></li>
    <li><a target=_blank title="[new window]" href="https://codepen.io/2kool2/pen/abzgPzJ">Light &amp; dark mode, with user switching button</a></li>
    <li><a target=_blank title="[new window]" href="https://websemantics.uk/tools/svg-to-background-image-conversion/">SVG to CSS background-image converter</a></li>
    <li><a target=_blank title="[new window]" href="https://websemantics.uk/tools/wcag-colour-contrast-checker/">WCAG colour contrast checker</a></li>
    <li><a target=_blank title="[new window]" href="https://prismjs.com/">Prism syntax highlighting</a></li>
    <li><a target=_blank title="[new window]" href="https://websemantics.uk/tools/escaping-html/">Escaping HTML symbols/entities</a></li>
<!--
    <li><a target=_blank title="[new window]" href=""></a></li>
-->
  </ul>

</body>

<style>

/* CSS included here to allow the main styles to be included into other CodePen projects */

*, *::after, *::before {
  box-sizing: inherit;
}
body {
  font-family: sans-serif;
  font-size: 1rem;
  text-rendering: optimizeLegibility;
  margin: 1rem;
  line-height: 1.5;
  padding-bottom: 2rem;
  background-attachment: fixed;
  background-image: url("data:image/svg+xml;charset=utf8,%3Csvg xmlns='http://www.w3.org/2000/svg'%3E%3Cdefs%3E%3Cfilter id='a'%3E%3CfeTurbulence type='fractalNoise' baseFrequency='.4'/%3E%3C/filter%3E%3C/defs%3E%3Crect filter='url(%23a)' opacity='.3' width='100%25' height='100%25'/%3E%3C/svg%3E");
}
h1 {
  font-weight: 100;
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}
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}
h2 {
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  margin-top: 3rem;
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}
p, li {
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ul, p {
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li {
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}
figure {
  margin: 2rem auto;
  max-width: 40rem;
}
figure + figure {
  margin-top: 3rem;
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figcaption {
  font-size: 1.25rem;
  font-weight: 100;
}
a:link,
a:visited {
  color: var(--linkColor);
  text-decoration-color: var(--linkColorUnderline);
}
a:hover {
  color: var(--linkColorHover);
  }
a:focus {
  color: var(--linkColorHover);
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</style>



<style id=action_button_animations>

/* Buttons (or links) */

[class^="actions_btn"],
[class^="actions_btn"]:visited {

  /* position: fixed;
  top: .5rem;
  right: .5rem; */

  /* button colors light */
  --btn-fg: #503660;
  --btn-bg: #fafafd;
  --btn-fg-hover: #418cec;
  --btn-bg-hover: #fff;

  box-sizing: content-box;
  display: block;
  width: 2.25rem;
  height: 2.25rem;
  padding: 0.25rem;
  color: var(--btn-fg);
  background-color: var(--btn-bg);
  border: 0.125rem solid transparent;
  border-radius: 50%;
  box-shadow: 0 0.25em 0.25em rgba(0, 0, 0, 0.3);
  text-decoration: none;
  outline: 0 solid;
  transition: all 0.3s ease-out;
}
[class^="actions_btn"]:hover,
[class^="actions_btn"]:focus {
  color: var(--btn-fg-hover);
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  border-color: var(--btn-fg-hover);
  transform: scale(1.2);
  box-shadow: 0 0.5em 0.5em rgba(0, 0, 0, 0.4);
}
[class^="actions_svg"] {
  width: 2.25rem;
  height: 2.25rem;
  fill: currentColor;
  stroke: currentColor;
  border-radius: 100%;
  overflow: hidden;
  pointer-events: none;
  transition: transform 0.5s ease-out;
}

/* Button click animation */

[class^="actions_btn"].-js-clicked {
  animation: actions_btn-clicked 0.3s ease-out forwards;
}
@keyframes actions_btn-clicked {
  0% {transform: scale(1.2);}
  50% {transform: scale(0.8);}
  100% {transform: scale(1.2);}
}

/* Remove all buttons from printouts */

@media print {
  [class^="actions_container"] {
    display: none !important;
  }
}
</style>




<!-- Codepen footer include -->
[[[https://codepen.io/2kool2/pen/mKeeGM]]]
!

CSS 

              
                /* PrismJS - used for code highlighting */

[class*="language-"] ::selection {
  color: #000;
  background: hsl(214, 100%, 85%);
  text-shadow: none;
}

pre[class*="language-"] {
  overflow: auto;
  margin: 0;
  background-color: transparent;
  
  /* Allow space for an overflow ellipsis */
  padding-right: 0.5rem;
  
  /* Allow space for SVG "tear off strip" */
  background-origin: border-box;
  border-left: 2.5rem solid transparent;
  background-size: 120rem 4rem;
  /* Single line does not sit on stripes */
  background-position: top -1.2rem left 0;
  
  /* Allow horizontal resizing - could be adjusted to allow vertical resizing too */
  position: relative;
  resize: horizontal;
  min-width: calc(100% - 3rem);
  
  transition: box-shadow .3s ease-out;
}

code[class*="language-"] {
  font-family: monospace, monospace;
  text-shadow: 0 1px var(--textShadow);
  letter-spacing: 0.01em;
  text-align: left;
  white-space: pre;
  word-spacing: normal;
  word-break: normal;

  /* Safari requirement for contenteditable */
  word-wrap: normal;
  line-height: 2;
  tab-size: 2;
  hyphens: none;
}

pre > code[class*="language-"],
pre[class*="language-"] > code {
  display: block;
  padding: 0.75rem 0;

  /* Use an ellipsis to indicate code is wider than the display area */
  text-overflow: ellipsis;
  overflow-x: scroll;
}
pre:hover > code[class*="language-"],
pre:focus-within > code[class*="language-"] {
  outline: none;
  text-overflow: inherit;
}

/* Inline code only */
:not(pre) > code[class*="language-"] {
  font-size: inherit;
  background-position: top right;
  background-size: auto 4rem;
  padding: 0.125em 0.25em;
  white-space: normal;
  word-wrap: nowrap;
}

.token.important,
.token.bold {
  font-weight: bold;
}
.token.italic {
  font-style: italic;
}
.token.entity {
  cursor: help;
}
.namespace {
  opacity: 0.7;
}

/* Default colors (Light mode) */
:not(pre) > code[class*="language-"],
pre[class*="language-"] {
  --color: #33a;
  --textShadow: #fff;
  --comment: #6e6e6e;
  --punctuation: #4e4e4e;
  --property: #905;
  --operator: #70b;
  --selector: #487b00;
  --url: #8d6640;
  --urlBg: hsla(0, 0%, 100%, .5);
  --boolean: #905;
  --atrule: #0075a8;
  --keyword: #0075a8;
  --function: #c93654;
  --regex: #860;
  --boxShadow: hsla(0,0%,0%,.3);
  --focusOutline: hsla(214, 100%, 85%, 1);
  
  --codeBgImg: url("data:image/svg+xml;charset=utf8,%3Csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 1920 64'%3E%3Ccircle stroke='rgba(0,64,0,.3)' stroke-width='2' fill='none' cx='20' cy='49' r='12'/%3E%3Cpath fill='%23fcfcfa' fill-rule='evenodd' d='M1920 64H0V0h1920v64zM20 36a11 11 0 110 22 11 11 0 010-22z'/%3E%3Cpath stroke='%23edf3ed' stroke-width='2' d='M0 1h1920M0 5h1920M0 9h1920M0 13h1920M0 17h1920M0 21h1920M0 25h1920M0 29h1920'/%3E%3Cpath stroke='%23e4ede4' stroke-dasharray='2 6 2 6' stroke-width='2' d='M40 2v60'/%3E%3C/svg%3E");
}


/* If the OS has dark mode set then... */
/* Change dark to light to test */

@media (prefers-color-scheme: dark) {
  body:not([data-lightMode="light"]) code[class*="language-"]:not([contenteditable]),
  body:not([data-lightMode="light"]) pre[class*="language-"] {
    --color: #6ae;
    --textShadow: #000;

    --comment: #9ab;
    --punctuation: #ccc;
    --property: #e70;
    --operator: #d7f;
    --selector: #8b2;
    --url: #cde;
    --urlBg: rgba(0,0,0,.5);
    --boolean: #a8f;
    --atrule: #ffb;
    --keyword: #fe6;
    --function: #f55;
    --regex: #f91;

    --boxShadow: #000;
    --focusOutline: hsla(214, 100%, 85%, .6);
  
    --codeBgImg: url("data:image/svg+xml;charset=utf8,%3Csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 1920 64'%3E%3Ccircle stroke='rgba(0,0,0,.7)' stroke-width='2' fill='none' cx='20' cy='49' r='12'/%3E%3Cpath fill='%23101610' fill-rule='evenodd' d='M1920 64H0V0h1920v64zM20 36a11 11 0 110 22 11 11 0 010-22z'/%3E%3Cpath stroke='%23121' stroke-width='2' d='M0 1h1920M0 5h1920M0 9h1920M0 13h1920M0 17h1920M0 21h1920M0 25h1920M0 29h1920'/%3E%3Cpath stroke='%23131' stroke-dasharray='2 6 2 6' stroke-width='2' d='M40 2v60'/%3E%3C/svg%3E");
  }
}

/* Manual switch mode - where implemented */
body[data-lightMode="dark"] code[class*="language-"]:not([contenteditable]),
body[data-lightMode="dark"] pre[class*="language-"] {

  /* Exactly the same as prefers-color-scheme: dark */
  --color: #6ae;
  --textShadow: #000;

  --comment: #9ab;
  --punctuation: #ccc;
  --property: #e70;
  --operator: #d7f;
  --selector: #8b2;
  --url: #cde;
  --urlBg: rgba(0,0,0,.5);
  --boolean: #8af;
  --atrule: #ffb;
  --keyword: #fe6;
  --function: #f55;
  --regex: #f91;

  --boxShadow: #000;
  --focusOutline: hsla(214, 100%, 85%, .6);
  
  --codeBgImg: url("data:image/svg+xml;charset=utf8,%3Csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 1920 64'%3E%3Ccircle stroke='rgba(0,0,0,.7)' stroke-width='2' fill='none' cx='20' cy='49' r='12'/%3E%3Cpath fill='%23101610' fill-rule='evenodd' d='M1920 64H0V0h1920v64zM20 36a11 11 0 110 22 11 11 0 010-22z'/%3E%3Cpath stroke='%23121' stroke-width='2' d='M0 1h1920M0 5h1920M0 9h1920M0 13h1920M0 17h1920M0 21h1920M0 25h1920M0 29h1920'/%3E%3Cpath stroke='%23131' stroke-dasharray='2 6 2 6' stroke-width='2' d='M40 2v60'/%3E%3C/svg%3E");
}



code[class*="language-"],
pre[class*="language-"] {
  color: var(--color);
  text-shadow: 0 1px var(--textShadow);
}

/* Background image is applied to the pre element on blocks, mainly because it is cropped when applied to the code element. */
:not(pre) > code[class*="language-"],
pre[class*="language-"] {
  background-image: var(--codeBgImg);
}
pre[class*="language-"]:hover,
pre[class*="language-"]:focus-within {
  box-shadow: 0 .25rem .25rem var(--boxShadow);
}
pre[class*="language-"]:focus-within {
  outline-offset: calc(-0.25rem - 1px);
  outline: var(--focusOutline) solid 0.25rem;
  z-index: 5;
}

.token.comment,
.token.prolog,
.token.doctype,
.token.cdata {
  color: var(--comment);
}
.token.punctuation {
  color: var(--punctuation);
}
.token.property,
.token.symbol,
.token.tag,
.token.constant,
.token.deleted {
  color: var(--property);
}
.token.boolean,
.token.number {
  color: var(--boolean);
}
.token.selector,
.token.attr-name,
.token.string,
.token.char,
.token.builtin,
.token.inserted {
  color: var(--selector);
}
.token.operator {
  color: var(--operator);
}
.token.url,
.token.entity,
.language-css .token.string,
.style .token.string {
  color: var(--url);
  background-color: var(--urlBg);
}
.token.atrule,
.token.attr-value {
  color: var(--atrule);
}
.token.keyword {
  color: var(--keyword);
}
.token.function {
  color: var(--function);
}
.token.regex,
.token.important,
.token.variable {
  color: var(--regex);
}



@media print {
  code[class*="language-"],
  pre[class*="language-"] {
    text-shadow: none;
  }
}
!

JS 

              
                // Prism - used for code highlighting
// http://prismjs.com/download.html?themes=prism&languages=markup+css+clike+javascript
var _self="undefined"!=typeof window?window:"undefined"!=typeof WorkerGlobalScope&&self instanceof WorkerGlobalScope?self:{},Prism=function(){var e=/\blang(?:uage)?-(\w+)\b/i,t=0,n=_self.Prism={manual:_self.Prism&&_self.Prism.manual,util:{encode:function(e){return e instanceof a?new a(e.type,n.util.encode(e.content),e.alias):"Array"===n.util.type(e)?e.map(n.util.encode):e.replace(/&/g,"&amp;").replace(/</g,"&lt;").replace(/\u00a0/g," ")},type:function(e){return Object.prototype.toString.call(e).match(/\[object (\w+)\]/)[1]},objId:function(e){return e.__id||Object.defineProperty(e,"__id",{value:++t}),e.__id},clone:function(e){var t=n.util.type(e);switch(t){case"Object":var a={};for(var r in e)e.hasOwnProperty(r)&&(a[r]=n.util.clone(e[r]));return a;case"Array":return e.map&&e.map(function(e){return n.util.clone(e)})}return e}},languages:{extend:function(e,t){var a=n.util.clone(n.languages[e]);for(var r in t)a[r]=t[r];return a},insertBefore:function(e,t,a,r){r=r||n.languages;var i=r[e];if(2==arguments.length){a=arguments[1];for(var l in a)a.hasOwnProperty(l)&&(i[l]=a[l]);return i}var o={};for(var s in i)if(i.hasOwnProperty(s)){if(s==t)for(var l in a)a.hasOwnProperty(l)&&(o[l]=a[l]);o[s]=i[s]}return n.languages.DFS(n.languages,function(t,n){n===r[e]&&t!=e&&(this[t]=o)}),r[e]=o},DFS:function(e,t,a,r){r=r||{};for(var i in e)e.hasOwnProperty(i)&&(t.call(e,i,e[i],a||i),"Object"!==n.util.type(e[i])||r[n.util.objId(e[i])]?"Array"!==n.util.type(e[i])||r[n.util.objId(e[i])]||(r[n.util.objId(e[i])]=!0,n.languages.DFS(e[i],t,i,r)):(r[n.util.objId(e[i])]=!0,n.languages.DFS(e[i],t,null,r)))}},plugins:{},highlightAll:function(e,t){var a={callback:t,selector:'code[class*="language-"], [class*="language-"] code, code[class*="lang-"], [class*="lang-"] code'};n.hooks.run("before-highlightall",a);for(var r,i=a.elements||document.querySelectorAll(a.selector),l=0;r=i[l++];)n.highlightElement(r,e===!0,a.callback)},highlightElement:function(t,a,r){for(var i,l,o=t;o&&!e.test(o.className);)o=o.parentNode;o&&(i=(o.className.match(e)||[,""])[1].toLowerCase(),l=n.languages[i]),t.className=t.className.replace(e,"").replace(/\s+/g," ")+" language-"+i,o=t.parentNode,/pre/i.test(o.nodeName)&&(o.className=o.className.replace(e,"").replace(/\s+/g," ")+" language-"+i);var s=t.textContent,u={element:t,language:i,grammar:l,code:s};if(n.hooks.run("before-sanity-check",u),!u.code||!u.grammar)return u.code&&(n.hooks.run("before-highlight",u),u.element.textContent=u.code,n.hooks.run("after-highlight",u)),n.hooks.run("complete",u),void 0;if(n.hooks.run("before-highlight",u),a&&_self.Worker){var g=new Worker(n.filename);g.onmessage=function(e){u.highlightedCode=e.data,n.hooks.run("before-insert",u),u.element.innerHTML=u.highlightedCode,r&&r.call(u.element),n.hooks.run("after-highlight",u),n.hooks.run("complete",u)},g.postMessage(JSON.stringify({language:u.language,code:u.code,immediateClose:!0}))}else u.highlightedCode=n.highlight(u.code,u.grammar,u.language),n.hooks.run("before-insert",u),u.element.innerHTML=u.highlightedCode,r&&r.call(t),n.hooks.run("after-highlight",u),n.hooks.run("complete",u)},highlight:function(e,t,r){var i=n.tokenize(e,t);return a.stringify(n.util.encode(i),r)},matchGrammar:function(e,t,a,r,i,l,o){var s=n.Token;for(var u in a)if(a.hasOwnProperty(u)&&a[u]){if(u==o)return;var g=a[u];g="Array"===n.util.type(g)?g:[g];for(var c=0;c<g.length;++c){var h=g[c],f=h.inside,d=!!h.lookbehind,m=!!h.greedy,p=0,y=h.alias;if(m&&!h.pattern.global){var v=h.pattern.toString().match(/[imuy]*$/)[0];h.pattern=RegExp(h.pattern.source,v+"g")}h=h.pattern||h;for(var b=r,k=i;b<t.length;k+=t[b].length,++b){var w=t[b];if(t.length>e.length)return;if(!(w instanceof s)){h.lastIndex=0;var _=h.exec(w),P=1;if(!_&&m&&b!=t.length-1){if(h.lastIndex=k,_=h.exec(e),!_)break;for(var A=_.index+(d?_[1].length:0),j=_.index+_[0].length,x=b,O=k,S=t.length;S>x&&(j>O||!t[x].type&&!t[x-1].greedy);++x)O+=t[x].length,A>=O&&(++b,k=O);if(t[b]instanceof s||t[x-1].greedy)continue;P=x-b,w=e.slice(k,O),_.index-=k}if(_){d&&(p=_[1].length);var A=_.index+p,_=_[0].slice(p),j=A+_.length,N=w.slice(0,A),C=w.slice(j),E=[b,P];N&&(++b,k+=N.length,E.push(N));var L=new s(u,f?n.tokenize(_,f):_,y,_,m);if(E.push(L),C&&E.push(C),Array.prototype.splice.apply(t,E),1!=P&&n.matchGrammar(e,t,a,b,k,!0,u),l)break}else if(l)break}}}}},tokenize:function(e,t){var a=[e],r=t.rest;if(r){for(var i in r)t[i]=r[i];delete t.rest}return n.matchGrammar(e,a,t,0,0,!1),a},hooks:{all:{},add:function(e,t){var a=n.hooks.all;a[e]=a[e]||[],a[e].push(t)},run:function(e,t){var a=n.hooks.all[e];if(a&&a.length)for(var r,i=0;r=a[i++];)r(t)}}},a=n.Token=function(e,t,n,a,r){this.type=e,this.content=t,this.alias=n,this.length=0|(a||"").length,this.greedy=!!r};if(a.stringify=function(e,t,r){if("string"==typeof e)return e;if("Array"===n.util.type(e))return e.map(function(n){return a.stringify(n,t,e)}).join("");var i={type:e.type,content:a.stringify(e.content,t,r),tag:"span",classes:["token",e.type],attributes:{},language:t,parent:r};if("comment"==i.type&&(i.attributes.spellcheck="true"),e.alias){var l="Array"===n.util.type(e.alias)?e.alias:[e.alias];Array.prototype.push.apply(i.classes,l)}n.hooks.run("wrap",i);var o=Object.keys(i.attributes).map(function(e){return e+'="'+(i.attributes[e]||"").replace(/"/g,"&quot;")+'"'}).join(" ");return"<"+i.tag+' class="'+i.classes.join(" ")+'"'+(o?" "+o:"")+">"+i.content+"</"+i.tag+">"},!_self.document)return _self.addEventListener?(_self.addEventListener("message",function(e){var t=JSON.parse(e.data),a=t.language,r=t.code,i=t.immediateClose;_self.postMessage(n.highlight(r,n.languages[a],a)),i&&_self.close()},!1),_self.Prism):_self.Prism;var r=document.currentScript||[].slice.call(document.getElementsByTagName("script")).pop();return r&&(n.filename=r.src,!document.addEventListener||n.manual||r.hasAttribute("data-manual")||("loading"!==document.readyState?window.requestAnimationFrame?window.requestAnimationFrame(n.highlightAll):window.setTimeout(n.highlightAll,16):document.addEventListener("DOMContentLoaded",n.highlightAll))),_self.Prism}();"undefined"!=typeof module&&module.exports&&(module.exports=Prism),"undefined"!=typeof global&&(global.Prism=Prism);
Prism.languages.markup={comment:/<!--[\s\S]*?-->/,prolog:/<\?[\s\S]+?\?>/,doctype:/<!DOCTYPE[\s\S]+?>/i,cdata:/<!\[CDATA\[[\s\S]*?]]>/i,tag:{pattern:/<\/?(?!\d)[^\s>\/=$<]+(?:\s+[^\s>\/=]+(?:=(?:("|')(?:\\\1|\\?(?!\1)[\s\S])*\1|[^\s'">=]+))?)*\s*\/?>/i,inside:{tag:{pattern:/^<\/?[^\s>\/]+/i,inside:{punctuation:/^<\/?/,namespace:/^[^\s>\/:]+:/}},"attr-value":{pattern:/=(?:('|")[\s\S]*?(\1)|[^\s>]+)/i,inside:{punctuation:/[=>"']/}},punctuation:/\/?>/,"attr-name":{pattern:/[^\s>\/]+/,inside:{namespace:/^[^\s>\/:]+:/}}}},entity:/&#?[\da-z]{1,8};/i},Prism.languages.markup.tag.inside["attr-value"].inside.entity=Prism.languages.markup.entity,Prism.hooks.add("wrap",function(a){"entity"===a.type&&(a.attributes.title=a.content.replace(/&amp;/,"&"))}),Prism.languages.xml=Prism.languages.markup,Prism.languages.html=Prism.languages.markup,Prism.languages.mathml=Prism.languages.markup,Prism.languages.svg=Prism.languages.markup;
Prism.languages.css={comment:/\/\*[\s\S]*?\*\//,atrule:{pattern:/@[\w-]+?.*?(;|(?=\s*\{))/i,inside:{rule:/@[\w-]+/}},url:/url\((?:(["'])(\\(?:\r\n|[\s\S])|(?!\1)[^\\\r\n])*\1|.*?)\)/i,selector:/[^\{\}\s][^\{\};]*?(?=\s*\{)/,string:{pattern:/("|')(\\(?:\r\n|[\s\S])|(?!\1)[^\\\r\n])*\1/,greedy:!0},property:/(\b|\B)[\w-]+(?=\s*:)/i,important:/\B!important\b/i,"function":/[-a-z0-9]+(?=\()/i,punctuation:/[(){};:]/},Prism.languages.css.atrule.inside.rest=Prism.util.clone(Prism.languages.css),Prism.languages.markup&&(Prism.languages.insertBefore("markup","tag",{style:{pattern:/(<style[\s\S]*?>)[\s\S]*?(?=<\/style>)/i,lookbehind:!0,inside:Prism.languages.css,alias:"language-css"}}),Prism.languages.insertBefore("inside","attr-value",{"style-attr":{pattern:/\s*style=("|').*?\1/i,inside:{"attr-name":{pattern:/^\s*style/i,inside:Prism.languages.markup.tag.inside},punctuation:/^\s*=\s*['"]|['"]\s*$/,"attr-value":{pattern:/.+/i,inside:Prism.languages.css}},alias:"language-css"}},Prism.languages.markup.tag));
Prism.languages.clike={comment:[{pattern:/(^|[^\\])\/\*[\s\S]*?\*\//,lookbehind:!0},{pattern:/(^|[^\\:])\/\/.*/,lookbehind:!0}],string:{pattern:/(["'])(\\(?:\r\n|[\s\S])|(?!\1)[^\\\r\n])*\1/,greedy:!0},"class-name":{pattern:/((?:\b(?:class|interface|extends|implements|trait|instanceof|new)\s+)|(?:catch\s+\())[a-z0-9_\.\\]+/i,lookbehind:!0,inside:{punctuation:/(\.|\\)/}},keyword:/\b(if|else|while|do|for|return|in|instanceof|function|new|try|throw|catch|finally|null|break|continue)\b/,"boolean":/\b(true|false)\b/,"function":/[a-z0-9_]+(?=\()/i,number:/\b-?(?:0x[\da-f]+|\d*\.?\d+(?:e[+-]?\d+)?)\b/i,operator:/--?|\+\+?|!=?=?|<=?|>=?|==?=?|&&?|\|\|?|\?|\*|\/|~|\^|%/,punctuation:/[{}[\];(),.:]/};
Prism.languages.javascript=Prism.languages.extend("clike",{keyword:/\b(as|async|await|break|case|catch|class|const|continue|debugger|default|delete|do|else|enum|export|extends|finally|for|from|function|get|if|implements|import|in|instanceof|interface|let|new|null|of|package|private|protected|public|return|set|static|super|switch|this|throw|try|typeof|var|void|while|with|yield)\b/,number:/\b-?(0[xX][\dA-Fa-f]+|0[bB][01]+|0[oO][0-7]+|\d*\.?\d+([Ee][+-]?\d+)?|NaN|Infinity)\b/,"function":/[_$a-zA-Z\xA0-\uFFFF][_$a-zA-Z0-9\xA0-\uFFFF]*(?=\()/i,operator:/-[-=]?|\+[+=]?|!=?=?|<<?=?|>>?>?=?|=(?:==?|>)?|&[&=]?|\|[|=]?|\*\*?=?|\/=?|~|\^=?|%=?|\?|\.{3}/}),Prism.languages.insertBefore("javascript","keyword",{regex:{pattern:/(^|[^\/])\/(?!\/)(\[[^\]\r\n]+]|\\.|[^\/\\\[\r\n])+\/[gimyu]{0,5}(?=\s*($|[\r\n,.;})]))/,lookbehind:!0,greedy:!0}}),Prism.languages.insertBefore("javascript","string",{"template-string":{pattern:/`(?:\\\\|\\?[^\\])*?`/,greedy:!0,inside:{interpolation:{pattern:/\$\{[^}]+\}/,inside:{"interpolation-punctuation":{pattern:/^\$\{|\}$/,alias:"punctuation"},rest:Prism.languages.javascript}},string:/[\s\S]+/}}}),Prism.languages.markup&&Prism.languages.insertBefore("markup","tag",{script:{pattern:/(<script[\s\S]*?>)[\s\S]*?(?=<\/script>)/i,lookbehind:!0,inside:Prism.languages.javascript,alias:"language-javascript"}}),Prism.languages.js=Prism.languages.javascript;
!
999px

Console