highlight.js

    <link
    rel="stylesheet"
    href="https://unpkg.com/@highlightjs/cdn-assets@11.7.0/styles/default.min.css"
  />

  <script src="https://unpkg.com/@highlightjs/cdn-assets@11.7.0/highlight.min.js"></script>
  <!-- and it's easy to individually load additional languages -->
  <script src="https://unpkg.com/@highlightjs/cdn-assets@11.7.0/languages/javascript.min.js"></script>
  <script>
    document.addEventListener('DOMContentLoaded', function() {
        document.querySelectorAll('pre code').forEach(function(block) {
            hljs.highlightBlock(block);
        });
    });
</script>

<script>
    function addCopyButtonToCodeBlock(codeBlock) {
        // Create a button element
        const copyButton = document.createElement('button');
        copyButton.className = 'copy-button';
        copyButton.textContent = 'Copy';
        copyButton.onclick = function () {
            copyToClipboard(codeBlock.textContent);
        };

        // Insert the button after the code block
        codeBlock.parentNode.insertBefore(copyButton, codeBlock.nextSibling);
    }

    function copyToClipboard(text) {
        const textarea = document.createElement('textarea');
        textarea.value = text;
        document.body.appendChild(textarea);
        textarea.select();
        document.execCommand('copy');
        document.body.removeChild(textarea);

        // Change button text momentarily to indicate successful copy
        const buttons = document.querySelectorAll('.copy-button');
        buttons.forEach(function (button) {
            if (button.textContent !== 'Copied!') {
                button.textContent = 'Copied!';
                setTimeout(function () {
                    button.textContent = 'Copy';
                }, 1000);
            }
        });
    }

    document.addEventListener('DOMContentLoaded', function () {
        document.querySelectorAll('pre code').forEach(function (block) {
            addCopyButtonToCodeBlock(block);
        });
        hljs.highlightAll();
    });
</script>

<style>
    pre {
        background-color: #f7f7f7;
        border: 1px solid #ddd;
        border-radius: 5px;
        padding: 1rem;
        overflow-x: auto;
    }

    code {
        font-family: Consolas, Monaco, 'Andale Mono', 'Ubuntu Mono', monospace;
    }
    
/*!
  Theme: GitHub Dark
  Description: Dark theme as seen on github.com
  Author: github.com
  Maintainer: @Hirse
  Updated: 2021-05-15

  Outdated base version: https://github.com/primer/github-syntax-dark
  Current colors taken from GitHub's CSS
*/
pre {
    background-color: #f7f7f7;
    border: 1px solid #ddd;
    border-radius: 5px;
    padding: 1rem;
    overflow-x: auto; /* This enables horizontal scrolling */
}

code {
    font-family: Consolas, Monaco, 'Andale Mono', 'Ubuntu Mono', monospace;
}

.hljs {
    color: #c9d1d9;
    background: #0d1117;
  }
  
  .hljs-doctag,
  .hljs-keyword,
  .hljs-meta .hljs-keyword,
  .hljs-template-tag,
  .hljs-template-variable,
  .hljs-type,
  .hljs-variable.language_ {
    /* prettylights-syntax-keyword */
    color: #ff7b72;
  }
  
  .hljs-title,
  .hljs-title.class_,
  .hljs-title.class_.inherited__,
  .hljs-title.function_ {
    /* prettylights-syntax-entity */
    color: #d2a8ff;
  }
  
  .hljs-attr,
  .hljs-attribute,
  .hljs-literal,
  .hljs-meta,
  .hljs-number,
  .hljs-operator,
  .hljs-variable,
  .hljs-selector-attr,
  .hljs-selector-class,
  .hljs-selector-id {
    /* prettylights-syntax-constant */
    color: #79c0ff;
  }
  
  .hljs-regexp,
  .hljs-string,
  .hljs-meta .hljs-string {
    /* prettylights-syntax-string */
    color: #a5d6ff;
  }
  
  .hljs-built_in,
  .hljs-symbol {
    /* prettylights-syntax-variable */
    color: #ffa657;
  }
  
  .hljs-comment,
  .hljs-code,
  .hljs-formula {
    /* prettylights-syntax-comment */
    color: #8b949e;
  }
  
  .hljs-name,
  .hljs-quote,
  .hljs-selector-tag,
  .hljs-selector-pseudo {
    /* prettylights-syntax-entity-tag */
    color: #7ee787;
  }
  
  .hljs-subst {
    /* prettylights-syntax-storage-modifier-import */
    color: #c9d1d9;
  }
  
  .hljs-section {
    /* prettylights-syntax-markup-heading */
    color: #1f6feb;
    font-weight: bold;
  }
  
  .hljs-bullet {
    /* prettylights-syntax-markup-list */
    color: #f2cc60;
  }
  
  .hljs-emphasis {
    /* prettylights-syntax-markup-italic */
    color: #c9d1d9;
    font-style: italic;
  }
  
  .hljs-strong {
    /* prettylights-syntax-markup-bold */
    color: #c9d1d9;
    font-weight: bold;
  }
  
  .hljs-addition {
    /* prettylights-syntax-markup-inserted */
    color: #aff5b4;
    background-color: #033a16;
  }
  
  .hljs-deletion {
    /* prettylights-syntax-markup-deleted */
    color: #ffdcd7;
    background-color: #67060c;
  }
  
  .hljs-char.escape_,
  .hljs-link,
  .hljs-params,
  .hljs-property,
  .hljs-punctuation,
  .hljs-tag {
    /* purposely ignored */
  }

</style>