diff --git a/src/app/globals.css b/src/app/globals.css
index 20db09ff5..95ee9ba77 100644
--- a/src/app/globals.css
+++ b/src/app/globals.css
@@ -33,6 +33,10 @@
 @custom-variant dark (&:is(.dark *));
 
 @theme inline {
+  /* Extra-small breakpoint (30rem / 480px) for the narrowest phones — the
+     default scale starts at sm (640px), which leaves a gap between an iPhone SE
+     and a small tablet where two-up grids of fixed-width content overflow. */
+  --breakpoint-xs: 30rem;
   --color-background: var(--background);
   --color-foreground: var(--foreground);
   --font-sans: var(--font-sans);
diff --git a/src/components/settings/security-section/passkey-list-section.tsx b/src/components/settings/security-section/passkey-list-section.tsx
index 03e1e6fc4..eda11e875 100644
--- a/src/components/settings/security-section/passkey-list-section.tsx
+++ b/src/components/settings/security-section/passkey-list-section.tsx
@@ -165,7 +165,7 @@ export function PasskeyListSection({
                           type="submit"
                           variant="ghost"
                           size="icon"
-                          className="h-8 w-8 shrink-0"
+                          className="min-h-11 min-w-11 shrink-0 sm:h-8 sm:min-h-0 sm:w-8 sm:min-w-0"
                           disabled={
                             rename.isPending || editName.trim().length === 0
                           }
@@ -181,7 +181,7 @@ export function PasskeyListSection({
                           type="button"
                           variant="ghost"
                           size="icon"
-                          className="h-8 w-8 shrink-0"
+                          className="min-h-11 min-w-11 shrink-0 sm:h-8 sm:min-h-0 sm:w-8 sm:min-w-0"
                           onClick={() => setEditingId(null)}
                           aria-label={t("common.cancel")}
                         >
diff --git a/src/components/settings/security-section/passkey-upgrade-nudge.tsx b/src/components/settings/security-section/passkey-upgrade-nudge.tsx
index e1d1caa2a..0f953ce0f 100644
--- a/src/components/settings/security-section/passkey-upgrade-nudge.tsx
+++ b/src/components/settings/security-section/passkey-upgrade-nudge.tsx
@@ -41,7 +41,7 @@ export function PasskeyUpgradeNudge() {
         type="button"
         variant="ghost"
         size="icon"
-        className="h-8 w-8 shrink-0"
+        className="min-h-11 min-w-11 shrink-0 sm:h-8 sm:min-h-0 sm:w-8 sm:min-w-0"
         onClick={() => dismiss.mutate()}
         disabled={dismiss.isPending}
         aria-label={t("common.dismiss")}
diff --git a/src/components/settings/security-section/recovery-codes-panel.tsx b/src/components/settings/security-section/recovery-codes-panel.tsx
index 858b0720d..84eee7741 100644
--- a/src/components/settings/security-section/recovery-codes-panel.tsx
+++ b/src/components/settings/security-section/recovery-codes-panel.tsx
@@ -53,7 +53,7 @@ export function RecoveryCodesPanel({ codes }: { codes: string[] }) {
         {t("settings.security.recovery.saveNowHint")}
       </p>
       <ul
-        className="mt-3 grid grid-cols-2 gap-2 font-mono text-sm"
+        className="xs:grid-cols-2 mt-3 grid grid-cols-1 gap-2 font-mono text-sm"
         data-testid="recovery-codes"
       >
         {codes.map((code) => (
diff --git a/src/components/settings/security-section/security-keys-card.tsx b/src/components/settings/security-section/security-keys-card.tsx
index 974df7b95..4a1a5353f 100644
--- a/src/components/settings/security-section/security-keys-card.tsx
+++ b/src/components/settings/security-section/security-keys-card.tsx
@@ -166,7 +166,7 @@ export function SecurityKeysCard({ keys }: { keys: WebauthnKeyInfo[] }) {
                           type="submit"
                           variant="ghost"
                           size="icon"
-                          className="h-8 w-8 shrink-0"
+                          className="min-h-11 min-w-11 shrink-0 sm:h-8 sm:min-h-0 sm:w-8 sm:min-w-0"
                           disabled={
                             rename.isPending || editName.trim().length === 0
                           }
@@ -182,7 +182,7 @@ export function SecurityKeysCard({ keys }: { keys: WebauthnKeyInfo[] }) {
                           type="button"
                           variant="ghost"
                           size="icon"
-                          className="h-8 w-8 shrink-0"
+                          className="min-h-11 min-w-11 shrink-0 sm:h-8 sm:min-h-0 sm:w-8 sm:min-w-0"
                           onClick={() => setEditingId(null)}
                           aria-label={t("common.cancel")}
                         >