foil.header.properties — Specifies properties for foil header area
    <xsl:attribute-set name="foil.header.properties">
      <xsl:attribute name="background-color">white</xsl:attribute>
      <xsl:attribute name="color">black</xsl:attribute>
      <xsl:attribute name="font-weight">bold</xsl:attribute>
      <xsl:attribute name="text-align">center</xsl:attribute>
      <xsl:attribute name="font-family">
        <xsl:value-of select="$slide.title.font.family"></xsl:value-of>
      </xsl:attribute>
      <xsl:attribute name="space-after">12pt</xsl:attribute>
    </xsl:attribute-set>