diff --git a/markitect/document_manager.py b/markitect/document_manager.py
index 4237b19a..57246bc1 100644
--- a/markitect/document_manager.py
+++ b/markitect/document_manager.py
@@ -630,7 +630,8 @@ class DocumentManager:
 
         .edit-mode textarea {
             width: 100%;
-            min-height: 100px;
+            min-height: 60px;
+            max-height: 400px;
             font-family: 'SF Mono', 'Monaco', 'Cascadia Code', 'Roboto Mono', monospace;
             border: 2px solid #007acc;
             border-radius: 6px;
@@ -638,6 +639,9 @@ class DocumentManager:
             font-size: 14px;
             line-height: 1.5;
             resize: vertical;
+            overflow-y: auto;
+            box-sizing: border-box;
+            transition: height 0.15s ease;
         }
 
         .edit-mode textarea:focus {
@@ -737,6 +741,39 @@ class DocumentManager:
                 textarea.value = this.htmlToMarkdown(originalContent);
                 textarea.className = 'edit-mode';
 
+                // Auto-sizing function
+                const autoResize = () => {
+                    // Temporarily disable transition for accurate measurement
+                    const transition = textarea.style.transition;
+                    textarea.style.transition = 'none';
+
+                    // Reset height to measure scrollHeight
+                    textarea.style.height = 'auto';
+
+                    // Calculate ideal height based on content
+                    const padding = 24; // 12px top + 12px bottom
+                    const lineHeight = 21; // 14px font-size * 1.5 line-height
+                    const minLines = 3; // Minimum of 3 lines
+                    const maxLines = 20; // Maximum of 20 lines
+
+                    const contentHeight = textarea.scrollHeight;
+                    const minHeight = (lineHeight * minLines) + padding;
+                    const maxHeight = (lineHeight * maxLines) + padding;
+
+                    const newHeight = Math.max(minHeight, Math.min(maxHeight, contentHeight));
+                    textarea.style.height = newHeight + 'px';
+
+                    // Re-enable transition
+                    textarea.style.transition = transition;
+                };
+
+                // Auto-resize on input and paste
+                textarea.addEventListener('input', autoResize);
+                textarea.addEventListener('paste', () => setTimeout(autoResize, 10));
+
+                // Initial sizing after DOM update
+                setTimeout(autoResize, 20);
+
                 textarea.addEventListener('blur', () => {
                     this.hasEdits = true; // Mark that edits have been made