Add Discord-style underline support and fix variable declaration in document loading

docs/index.md

@@ -14,4 +14,4 @@ If you need help or have questions:
 - Join the discussion on [Discord](https://discord.gg/b8ctQBaaax)
 
 
-asdfds
+__asdfds__

index.js

@@ -275,7 +275,7 @@ async function loadDocument(path) {
 
         processedContent = `# ${titleContent}\n\n${processedContent}`;
 
-        const finalContent = processedContent.replace(/!\[\[(.*?)\]\]/g, (match, filename) => {
+        let finalContent = processedContent.replace(/!\[\[(.*?)\]\]/g, (match, filename) => {
             const mediaPath = `${basePath}/images/${filename}`;
             
             if (filename.toLowerCase().endsWith('.mp4')) {
@@ -288,6 +288,9 @@ async function loadDocument(path) {
             return `\n![${filename}](${mediaPath})\n\n`;
         });
 
+        // Add Discord-style underline support: __text__ -> <u>text</u>
+        finalContent = finalContent.replace(/__(.*?)__/g, '<u>$1</u>');
+
         document.querySelector('.title-text .page-title').textContent = titleContent;
 
         documentContent.className = 'markdown-content';