rssguard/resources/skins/plain/metadata.xml

<?xml version="1.0" encoding="UTF-8"?>
<skin version="0.666">
  <author>
    <name>Martin Rotter</name>
  </author>
  <default-font>
    <family>Pacifico</family>
    <size>9</size> <!-- in points -->
  </default-font>
  <palette>
    <!--
      Keys are defined in file
        "https://github.com/martinrotter/rssguard/blob/master/src/librssguard/miscellaneous/skinfactory.h"

      Specifically, they are taken from enumeration "PaletteColors".
    -->
    <color key="FgInteresting">#3A4EE4</color>
    <color key="FgSelectedInteresting">#ff66cc</color>

    <color key="FgNewMessages">#3A4EE4</color>
    <color key="FgSelectedNewMessages">#ff66cc</color>

    <color key="FgError">#4EE43A</color>
    <color key="FgSelectedError">#ff99ff</color>

    <color key="Allright">#00ff99</color>
  </palette>
</skin>