refac

src/lib/components/chat/Chat.svelte

@@ -1463,6 +1463,29 @@
 				top: messagesContainerElement.scrollHeight,
 				behavior
 			});
+
+			// content-visibility: auto causes the initial scrollHeight to be based on
+			// estimated sizes (contain-intrinsic-size). After we scroll, previously
+			// off-screen messages become visible and the browser resolves their actual
+			// heights, which shifts scrollHeight. Re-layouts can cascade across frames
+			// (new sizes reveal more content, triggering further size resolution), so
+			// we re-scroll across two animation frames to land at the true bottom.
+			requestAnimationFrame(() => {
+				if (messagesContainerElement) {
+					messagesContainerElement.scrollTo({
+						top: messagesContainerElement.scrollHeight,
+						behavior
+					});
+					requestAnimationFrame(() => {
+						if (messagesContainerElement) {
+							messagesContainerElement.scrollTo({
+								top: messagesContainerElement.scrollHeight,
+								behavior
+							});
+						}
+					});
+				}
+			});
 		}
 	};
 

src/lib/components/chat/Messages.svelte

@@ -140,7 +140,16 @@
 
 	const scrollToBottom = () => {
 		const element = document.getElementById('messages-container');
-		element.scrollTop = element.scrollHeight;
+		if (element) {
+			element.scrollTop = element.scrollHeight;
+
+			// Follow-up scroll to account for content-visibility: auto re-layouts
+			requestAnimationFrame(() => {
+				if (element) {
+					element.scrollTop = element.scrollHeight;
+				}
+			});
+		}
 	};
 
 	export const scrollToTop = async () => {