<xs:attribute name="fontstyle" default="regular" xmlns:xs="http://www.w3.org/2001/XMLSchema">
  <xs:simpleType>
    <xs:restriction base="xs:string">
      <xs:enumeration value="regular" />
      <xs:enumeration value="bold" />
      <xs:enumeration value="italic" />
      <xs:enumeration value="underline" />
      <xs:enumeration value="strikeout" />
    </xs:restriction>
  </xs:simpleType>
</xs:attribute>