diff --git a/src/ui/ToolCallBlock.tsx b/src/ui/ToolCallBlock.tsx
index 7b9b1e1..9449b79 100644
--- a/src/ui/ToolCallBlock.tsx
+++ b/src/ui/ToolCallBlock.tsx
@@ -449,9 +449,10 @@ function DiffRenderer({
 							? `${remainingLines} more lines`
 							: "Collapse"}
 					</span>
-					<span className="agent-client-diff-expand-icon">
-						{isCollapsed ? "▶" : "▲"}
-					</span>
+					<LucideIcon
+						name={isCollapsed ? "chevron-right" : "chevron-up"}
+						className="agent-client-diff-expand-icon"
+					/>
 				</div>
 			)}
 		</div>
diff --git a/styles.css b/styles.css
index cea9827..3342040 100644
--- a/styles.css
+++ b/styles.css
@@ -1413,7 +1413,7 @@ If your plugin does not need CSS, delete this file.
 	display: flex;
 	align-items: center;
 	justify-content: center;
-	padding: 6px 12px;
+	padding: 3px 12px;
 	background-color: var(--background-secondary-alt);
 	border-top: 1px solid var(--background-modifier-border);
 	cursor: pointer;
@@ -1432,11 +1432,17 @@ If your plugin does not need CSS, delete this file.
 }
 
 .agent-client-diff-expand-icon {
-	font-size: 0.8em;
+	display: flex;
+	align-items: center;
 	color: var(--text-muted);
 	margin-left: 8px;
 }
 
+.agent-client-diff-expand-icon svg {
+	width: 14px;
+	height: 14px;
+}
+
 /* Tool Call Details */
 .agent-client-tool-call-read-details,
 .agent-client-tool-call-edit-details,