diff --git a/.jules/palette.md b/.jules/palette.md
new file mode 100644
index 00000000..8da0349d
--- /dev/null
+++ b/.jules/palette.md
@@ -0,0 +1,3 @@
+## 2024-05-15 - Enhancing Generated File Tree HTML
+**Learning:** Raw directory listings generated into HTML often lack critical accessibility meta tags (like `lang="en"`, `viewport` for responsive scaling) and aria-labels for directory/file links (which are otherwise non-descriptive for screen readers like just `&#128193; folderName`).
+**Action:** Always include base semantic structures (`<main>`, `<html lang="en">`, responsive meta tags) and `aria-label`s specifying the entity type (e.g., `folderName directory`) when generating raw navigation trees to ensure keyboard and screen-reader usability. Add `:focus` styles mimicking `:hover` for keyboard users.
diff --git a/src/main/kotlin/html4tree/main.kt b/src/main/kotlin/html4tree/main.kt
index 50b2680d..5dca48bb 100644
--- a/src/main/kotlin/html4tree/main.kt
+++ b/src/main/kotlin/html4tree/main.kt
@@ -99,6 +99,7 @@ fun process_dir(curr_dir: File){
                 padding: 0.5rem;
                 text-decoration: none;
                 color: #0366d6;
+                border-radius: 4px;
               }
               a:hover, a:focus-visible {
                 background-color: #f6f8fa;
@@ -118,9 +119,10 @@ fun process_dir(curr_dir: File){
         ${css}
      </head>
      <body>
-       <h1>${curr_dir.getName().escapeHtml()}</h1>
-       <ul>
-          <li><a style="display:block; width:100%" href="./.." aria-label="상위 디렉토리로 이동">&#x21B0; ..</a></li>
+       <main>
+         <h1>${curr_dir.getName().escapeHtml()}</h1>
+         <ul>
+            <li><a style="display:block; width:100%" href="./.." aria-label="상위 디렉토리로 이동">&#x21B0; ..</a></li>
 """ 
 
     val index_middle = fun():String{ 
@@ -131,7 +133,10 @@ fun process_dir(curr_dir: File){
         dir_files.forEach {
            val isLinkedDirectory = it.isDirectory() && !java.nio.file.Files.isSymbolicLink(it.toPath())
            if((it.getName() !in exclude) && (isLinkedDirectory || !it.isDirectory())) {
-              l += """          <li><a style="display:block; width:100%" href="${if (isLinkedDirectory) { "./${it.getName().urlEncodePath()}/" } else { "./${it.getName().urlEncodePath()}" }}">${if (isLinkedDirectory) { "&#128193;" } else { "&rtrif;" }} ${it.getName().escapeHtml()}</a></li>"""+"\n"
+              val fileName = it.getName()
+              val encodedHref = if (isLinkedDirectory) { "./${fileName.urlEncodePath()}/" } else { "./${fileName.urlEncodePath()}" }
+              val ariaLabel = "${fileName} ${if (isLinkedDirectory) { "디렉토리" } else { "파일" }}".escapeHtml()
+              l += """          <li><a style="display:block; width:100%" href="${encodedHref}" aria-label="${ariaLabel}">${if (isLinkedDirectory) { "&#128193;" } else { "&rtrif;" }} ${fileName.escapeHtml()}</a></li>"""+"\n"
            }
         }
 
@@ -139,7 +144,8 @@ fun process_dir(curr_dir: File){
      } 
 
    val index_bottom="""
-       </ul>
+         </ul>
+       </main>
     </body>
 </html>
 """
diff --git a/src/main/kotlin/html4tree/util.kt b/src/main/kotlin/html4tree/util.kt
index 9a882d74..c8979c31 100644
--- a/src/main/kotlin/html4tree/util.kt
+++ b/src/main/kotlin/html4tree/util.kt
@@ -39,7 +39,7 @@ class LinkedList {
         if(l == null){
             return null
         } else {
-        	l.next = null
+            l.next = null
             return LinkedListEntry(l.data, l.level)
         }
     }
diff --git a/src/test/kotlin/html4tree/MainTest.kt b/src/test/kotlin/html4tree/MainTest.kt
index 31c193a2..1cd3188a 100644
--- a/src/test/kotlin/html4tree/MainTest.kt
+++ b/src/test/kotlin/html4tree/MainTest.kt
@@ -110,7 +110,11 @@ class MainTest {
         assertTrue(indexFile.exists())
         val htmlContent = indexFile.readText()
         assertTrue(htmlContent.contains("<html lang=\"ko\">"))
+        assertTrue(htmlContent.contains("<main>"))
+        assertTrue(htmlContent.contains("</main>"))
         assertTrue(htmlContent.contains("aria-label=\"상위 디렉토리로 이동\""))
+        assertTrue(htmlContent.contains("aria-label=\"file1.txt 파일\""))
+        assertTrue(htmlContent.contains("aria-label=\"subdir 디렉토리\""))
         assertTrue(htmlContent.contains("file1.txt"))
         assertTrue(htmlContent.contains("subdir/"))
         assertTrue(htmlContent.contains("&#128193;"))
