it will be in the MXM_Skin.xml file . you will scroll down to where it says
<LayoutElement Type="Box">
<Pos l="373" t="107" w="232" h="302" />
<Timer Type="delay">1725</Timer>
<Color>0x80303030</Color>
</LayoutElement>
<LayoutElement Type="Menu" Source="MXM">
<Timer Type="delay">1725</Timer>
<Pos l="373" t="107" w="232" h="302" />
<Scale x="false" y="true" />
<SelPos>1</SelPos>
<NumItems>7</NumItems>
<Thumbnails Align="left" FolderImg="Folder" PassImg="Lock">false</Thumbnails>
<MinimumHeight>0</MinimumHeight>
<DrawSecondary>True</DrawSecondary>
<ScrollFactor>8</ScrollFactor>
<Primary Source="Title">
<Font>MenuTitleFont</Font>
<OffsetY>0</OffsetY>
<JustifyX>left</JustifyX>
</Primary>
<Secondary Source="Descr">
<Font>MenuDescrFont</Font>
<OffsetY>0</OffsetY>
<JustifyX>right</JustifyX>
</Secondary>
<Selection>
<TextColor>0xFFa0FFa0</TextColor>
<ShadowColor>0xFF000000</ShadowColor>
<DoGlow>True</DoGlow>
<Modifier Type="Throb" Target="TextColor">
<Green Enable="true" Min="150" Max="255" Period="600" />
<Red Enable="true" Min="100" Max="155" Period="600" />
<Blue Enable="true" Min="100" Max="155" Period="600" />
</Modifier>
</Selection>
<UnSelItem>
<TextColor>0xFFa0a0a0</TextColor>
<ShadowColor>0xFF000000</ShadowColor>
<DoGlow>False</DoGlow>
</Modifier>
</UnSelItem>
</LayoutElement>
<LayoutElement Type="Triangle" Direction="Up">
<Timer Type="delay">1725</Timer>
<Pos l="473" t="82" w="60" h="24" />
<BorderColor>0xFF000000</BorderColor>
<Color>0xFF80FF80</Color>
<Condition>itemprev</Condition>
<Modifier Type="Throb" Target="Color">
<Alpha Enable="true" Min="190" Max="255" Period="600" />
<Blue Enable="true" Min="130" Max="200" Period="600" />
<Red Enable="true" Min="130" Max="200" Period="600" />
<Green Enable="true" Min="150" Max="255" Period="600" />
</Modifier>
</LayoutElement>
<LayoutElement Type="Triangle" Direction="Down">
<Timer Type="delay">1725</Timer>
<Pos l="473" t="409" w="60" h="24" />
<Condition>itemnext</Condition>
<BorderColor>0xFF000000</BorderColor>
<Color>0xFF80FF80</Color>
<Modifier Type="Throb" Target="Color">
<Alpha Enable="true" Min="190" Max="255" Period="600" />
<Blue Enable="true" Min="130" Max="200" Period="600" />
<Red Enable="true" Min="130" Max="200" Period="600" />
<Green Enable="true" Min="150" Max="255" Period="600" />
</Modifier>
</LayoutElement>
and then change the values I have marked in red to values that are better suited for your display