--- a/src/edit_course.html.luan	Mon Aug 11 07:58:32 2025 +0900
+++ b/src/edit_course.html.luan	Mon Aug 11 08:27:22 2025 +0900
@@ -67,10 +67,10 @@
 			<input type=text required name=name value="<%=html_encode(course.name)%>">
 
 			<h4>AI system prompt</h4>
-			<textarea required name=ai_system_prompt rows=10><%=html_encode(course.ai_system_prompt)%></textarea>
+			<textarea required name=ai_system_prompt oninput="fixTextarea(event.target)"><%=html_encode(course.ai_system_prompt)%></textarea>
 
 			<h4>AI first message (optional)</h4>
-			<textarea name=ai_first_message><%=html_encode(course.ai_first_message or "")%></textarea>
+			<textarea name=ai_first_message oninput="fixTextarea(event.target)"><%=html_encode(course.ai_first_message or "")%></textarea>
 
 			<input type=submit>
 
@@ -78,6 +78,13 @@
 
 			<p>Text areas take <a href="/tools/markdown.html">Markdown</a>.  AI generally recognizes Markdown.</p>
 		</form>
+		<script>
+			'use strict';
+			let textareas = document.querySelectorAll('textarea');
+			for( let textarea of textareas ) {
+				fixTextarea(textarea);
+			}
+		</script>
 	</body>
 </html>
 <%