diff --git a/frontend/src/routes/stammbaum/+page.svelte b/frontend/src/routes/stammbaum/+page.svelte
index 6afc1702..b570a98b 100644
--- a/frontend/src/routes/stammbaum/+page.svelte
+++ b/frontend/src/routes/stammbaum/+page.svelte
@@ -49,7 +49,7 @@ function zoomOut() {
 					type="button"
 					onclick={zoomOut}
 					aria-label={m.stammbaum_zoom_out()}
-					class="inline-flex h-11 w-11 items-center justify-center rounded-sm border border-line bg-surface text-ink-2 transition hover:bg-muted"
+					class="inline-flex h-11 w-11 items-center justify-center rounded-sm border border-line bg-surface text-ink-2 transition hover:bg-muted focus-visible:ring-2 focus-visible:ring-focus-ring focus-visible:outline-none"
 				>
 					−
 				</button>
@@ -57,7 +57,7 @@ function zoomOut() {
 					type="button"
 					onclick={zoomIn}
 					aria-label={m.stammbaum_zoom_in()}
-					class="inline-flex h-11 w-11 items-center justify-center rounded-sm border border-line bg-surface text-ink-2 transition hover:bg-muted"
+					class="inline-flex h-11 w-11 items-center justify-center rounded-sm border border-line bg-surface text-ink-2 transition hover:bg-muted focus-visible:ring-2 focus-visible:ring-focus-ring focus-visible:outline-none"
 				>
 					+
 				</button>