diff --git a/src/scripts/renderer.ts b/src/scripts/renderer.ts
index 8f0f468c..cbdda42e 100644
--- a/src/scripts/renderer.ts
+++ b/src/scripts/renderer.ts
@@ -412,6 +412,7 @@ try {
 	let defaultSize = parseInt(loc("WebClipper.FontSize.Preview.SansSerifDefault", "16px"), 10);
 	if (defaultSize > 0) { articleFontSize = defaultSize; }
 } catch (e) { /* keep default 16 */ }
+updateFontSizeButtonStates();
 
 // Document title is set unconditionally; the page title and source URL arrive
 // in the loadContent port message and are populated there (no session-storage
@@ -1429,6 +1430,11 @@ function applyArticleFontSize() {
 	pDoc.body.style.fontSize = articleFontSize + "px";
 }
 
+function updateFontSizeButtonStates() {
+	fontDecreaseBtn.setAttribute("aria-disabled", articleFontSize <= 8 ? "true" : "false");
+	fontIncreaseBtn.setAttribute("aria-disabled", articleFontSize >= 72 ? "true" : "false");
+}
+
 function initHighlighter() {
 	// Parent-window script operating on the sandboxed (allow-same-origin) preview-frame.
 	createHighlighterInstance();
@@ -1525,12 +1531,14 @@ fontDecreaseBtn.addEventListener("click", () => {
 	if (articleFontSize <= 8) { return; }
 	articleFontSize -= 2;
 	applyArticleFontSize();
+	updateFontSizeButtonStates();
 	announceToScreenReader(strings.decreaseFontSize);
 });
 fontIncreaseBtn.addEventListener("click", () => {
 	if (articleFontSize >= 72) { return; }
 	articleFontSize += 2;
 	applyArticleFontSize();
+	updateFontSizeButtonStates();
 	announceToScreenReader(strings.increaseFontSize);
 });
 
diff --git a/src/styles/renderer.less b/src/styles/renderer.less
index 6126ee4c..b2894de7 100644
--- a/src/styles/renderer.less
+++ b/src/styles/renderer.less
@@ -161,8 +161,9 @@ iframe#preview-frame {
 		color: @colorNeutralForeground1; cursor: pointer; border-radius: 4px;
 		height: 28px; vertical-align: middle; padding: 0;
 		transition: background 0.1s;
-		&:hover:not(.active) { background: @colorSubtleBackgroundHover; }
+		&:hover:not(.active):not([aria-disabled="true"]) { background: @colorSubtleBackgroundHover; }
 		&:focus { outline: 2px solid @focusRingColor !important; outline-offset: 2px; }
+		&[aria-disabled="true"] { opacity: 0.4; cursor: default; }
 		&.active {
 			background: @colorSubtleBackgroundHover;
 			border-color: @colorCompoundBrandBackground;