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feat: implement CSS-variable based syntax highlighting for dark mode #38

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Merged
ThisIs-Developer merged 1 commit into from
Mar 7, 2026
+99 −27
Merged

feat: implement CSS-variable based syntax highlighting for dark mode #38

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3 changes: 1 addition & 2 deletions index.html
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Original file line number Diff line number Diff line change
Expand Up @@ -32,7 +32,6 @@
<!-- Updated libraries to latest versions -->
<link rel="stylesheet" href="https://cdnjs.cloudflare.com/ajax/libs/bootstrap/5.3.2/css/bootstrap.min.css">
<link rel="stylesheet" href="https://cdnjs.cloudflare.com/ajax/libs/github-markdown-css/5.3.0/github-markdown.min.css">
<link rel="stylesheet" id="highlight-theme" href="https://cdnjs.cloudflare.com/ajax/libs/highlight.js/11.9.0/styles/github.min.css">
<link rel="stylesheet" href="https://cdn.jsdelivr.net/npm/bootstrap-icons@1.11.3/font/bootstrap-icons.min.css">
<link rel="stylesheet" href="https://cdn.jsdelivr.net/npm/emoji-toolkit@9.0.1/extras/css/joypixels.min.css">
<link rel="stylesheet" href="styles.css">
Expand Down Expand Up @@ -268,4 +267,4 @@ <h5>Menu</h5>
<script src="https://cdnjs.cloudflare.com/ajax/libs/bootstrap/5.3.2/js/bootstrap.bundle.min.js"></script>
<script src="script.js"></script>
</body>
</html>
</html>
42 changes: 20 additions & 22 deletions script.js
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Original file line number Diff line number Diff line change
Expand Up @@ -121,11 +121,6 @@ document.addEventListener("DOMContentLoaded", function () {
marked.setOptions({
...markedOptions,
renderer: renderer,
highlight: function (code, language) {
if (language === 'mermaid') return code;
const validLanguage = hljs.getLanguage(language) ? language : "plaintext";
return hljs.highlight(code, { language: validLanguage }).value;
},
});

const sampleMarkdown = `# Welcome to Markdown Viewer
Expand All @@ -145,10 +140,9 @@ document.addEventListener("DOMContentLoaded", function () {
const sanitizedHtml = DOMPurify.sanitize(html);
markdownPreview.innerHTML = sanitizedHtml;

// Apply syntax highlighting to code blocks
markdownPreview.querySelectorAll('pre code').forEach((block) => {
hljs.highlightElement(block);
});
// Syntax highlighting is handled automatically
// during the parsing phase by the marked renderer.
// Themes are applied instantly via CSS variables.
}
\`\`\`

Expand Down Expand Up @@ -302,16 +296,6 @@ This is a fully client-side application. Your content never leaves your browser
});
markdownPreview.innerHTML = sanitizedHtml;

markdownPreview.querySelectorAll("pre code").forEach((block) => {
try {
if (!block.classList.contains('mermaid') && !block.classList.contains('hljs')) {
hljs.highlightElement(block);
}
} catch (e) {
console.warn("Syntax highlighting failed for a code block:", e);
}
});

processEmojis(markdownPreview);

// Reinitialize mermaid with current theme before rendering diagrams
Expand Down Expand Up @@ -813,9 +797,6 @@ This is a fully client-side application. Your content never leaves your browser
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>Markdown Export</title>
<link rel="stylesheet" href="${cssTheme}">
<link rel="stylesheet" href="https://cdnjs.cloudflare.com/ajax/libs/highlight.js/11.9.0/styles/${
isDarkTheme ? "github-dark" : "github"
}.min.css">
<style>
body {
background-color: ${isDarkTheme ? "#0d1117" : "#ffffff"};
Expand All @@ -830,6 +811,23 @@ This is a fully client-side application. Your content never leaves your browser
background-color: ${isDarkTheme ? "#0d1117" : "#ffffff"};
color: ${isDarkTheme ? "#c9d1d9" : "#24292e"};
}

/* Syntax Highlighting */
.hljs-doctag, .hljs-keyword, .hljs-template-tag, .hljs-template-variable, .hljs-type, .hljs-variable.language_ { color: ${isDarkTheme ? "#ff7b72" : "#d73a49"}; }
.hljs-title, .hljs-title.class_, .hljs-title.class_.inherited__, .hljs-title.function_ { color: ${isDarkTheme ? "#d2a8ff" : "#6f42c1"}; }
.hljs-attr, .hljs-attribute, .hljs-literal, .hljs-meta, .hljs-number, .hljs-operator, .hljs-variable, .hljs-selector-attr, .hljs-selector-class, .hljs-selector-id { color: ${isDarkTheme ? "#79c0ff" : "#005cc5"}; }
.hljs-regexp, .hljs-string, .hljs-meta .hljs-string { color: ${isDarkTheme ? "#a5d6ff" : "#032f62"}; }
.hljs-built_in, .hljs-symbol { color: ${isDarkTheme ? "#ffa657" : "#e36209"}; }
.hljs-comment, .hljs-code, .hljs-formula { color: ${isDarkTheme ? "#8b949e" : "#6a737d"}; }
.hljs-name, .hljs-quote, .hljs-selector-tag, .hljs-selector-pseudo { color: ${isDarkTheme ? "#7ee787" : "#22863a"}; }
.hljs-subst { color: ${isDarkTheme ? "#c9d1d9" : "#24292e"}; }
.hljs-section { color: ${isDarkTheme ? "#1f6feb" : "#005cc5"}; font-weight: bold; }
.hljs-bullet { color: ${isDarkTheme ? "#79c0ff" : "#005cc5"}; }
.hljs-emphasis { font-style: italic; }
.hljs-strong { font-weight: bold; }
.hljs-addition { color: ${isDarkTheme ? "#aff5b4" : "#22863a"}; background-color: ${isDarkTheme ? "#033a16" : "#f0fff4"}; }
.hljs-deletion { color: ${isDarkTheme ? "#ffdcd7" : "#b31d28"}; background-color: ${isDarkTheme ? "#67060c" : "#ffeef0"}; }

@media (max-width: 767px) {
.markdown-body {
padding: 15px;
Expand Down
81 changes: 78 additions & 3 deletions styles.css
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Original file line number Diff line number Diff line change
Expand Up @@ -413,8 +413,82 @@ a:focus {
background-color: var(--code-bg);
}

[data-theme="dark"] .hljs {
color: #e8eaed;
/* Syntax Highlighting Mapping to GitHub Variables */
.hljs {
color: var(--color-fg-default);
}
.hljs-doctag,
.hljs-keyword,
.hljs-meta .hljs-keyword,
.hljs-template-tag,
.hljs-template-variable,
.hljs-type,
.hljs-variable.language_ {
color: var(--color-prettylights-syntax-keyword);
}
.hljs-title,
.hljs-title.class_,
.hljs-title.class_.inherited__,
.hljs-title.function_ {
color: var(--color-prettylights-syntax-entity);
}
.hljs-attr,
.hljs-attribute,
.hljs-literal,
.hljs-meta,
.hljs-number,
.hljs-operator,
.hljs-variable,
.hljs-selector-attr,
.hljs-selector-class,
.hljs-selector-id {
color: var(--color-prettylights-syntax-constant);
}
.hljs-regexp,
.hljs-string,
.hljs-meta .hljs-string {
color: var(--color-prettylights-syntax-string);
}
.hljs-built_in,
.hljs-symbol {
color: var(--color-prettylights-syntax-variable);
}
.hljs-comment,
.hljs-code,
.hljs-formula {
color: var(--color-prettylights-syntax-comment);
}
.hljs-name,
.hljs-quote,
.hljs-selector-tag,
.hljs-selector-pseudo {
color: var(--color-prettylights-syntax-entity-tag);
}
.hljs-subst {
color: var(--color-fg-default);
}
.hljs-section {
color: var(--color-prettylights-syntax-markup-heading);
font-weight: bold;
}
.hljs-bullet {
color: var(--color-prettylights-syntax-constant);
}
.hljs-emphasis {
color: var(--color-fg-default);
font-style: italic;
}
.hljs-strong {
color: var(--color-fg-default);
font-weight: bold;
}
.hljs-addition {
color: var(--color-prettylights-syntax-markup-inserted-text);
background-color: var(--color-prettylights-syntax-markup-inserted-bg);
}
.hljs-deletion {
color: var(--color-prettylights-syntax-markup-deleted-text);
background-color: var(--color-prettylights-syntax-markup-deleted-bg);
}

.stats-container {
Expand Down Expand Up @@ -1104,4 +1178,5 @@ a:focus {

.mermaid-modal-controls .mermaid-toolbar-btn {
opacity: 1;
}
}

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