Include the CSS in the SVG within a <style> tag

Include the CSS in the SVG within a <style> tag.html

<svg xmlns="http://www.w3.org/2000/svg" width="48" height="48" viewBox="0 0 48 48">
  <!-- Note the <style> tag is included within the SVG -->
  <style type="text/css" >
      <![CDATA[
        rect {
           fill:   #333;
        }
      ]]>
  </style>
  <g>
    <rect id="vertical-rectangle" width="48" height="4" x="1" y="23" transform="rotate(90 25 24)"/>
    <rect id="horizontal-rectangle" width="48" height="4" y="21"/>
  </g>
</svg>