Small layout improvement

app/src/main/res/layout/dialog_certificate.xml

@@ -24,7 +24,7 @@
             android:layout_height="wrap_content"
             android:layout_marginTop="24dp"
             android:text="@string/title_signature_certificate_invalid"
-            android:textAppearance="@style/TextAppearance.AppCompat.Small"
+            android:textAppearance="@style/TextAppearance.AppCompat.Medium"
             android:textColor="?attr/colorWarning"
             app:layout_constraintStart_toStartOf="parent"
             app:layout_constraintTop_toBottomOf="@id/tvCaption" />
@@ -73,7 +73,7 @@
             android:layout_height="wrap_content"
             android:layout_marginTop="12dp"
             android:text="@string/title_signature_mismatch"
-            android:textAppearance="@style/TextAppearance.AppCompat.Small"
+            android:textAppearance="@style/TextAppearance.AppCompat.Medium"
             android:textColor="?attr/colorWarning"
             app:layout_constraintStart_toStartOf="parent"
             app:layout_constraintTop_toBottomOf="@id/tvEmail" />
@@ -134,7 +134,7 @@
             android:layout_height="wrap_content"
             android:layout_marginTop="12dp"
             android:text="@string/title_signature_outdated"
-            android:textAppearance="@style/TextAppearance.AppCompat.Small"
+            android:textAppearance="@style/TextAppearance.AppCompat.Medium"
             android:textColor="?attr/colorWarning"
             app:layout_constraintStart_toStartOf="parent"
             app:layout_constraintTop_toBottomOf="@id/tvAfter" />