Additional notes for legacy: dbtech_thanks.css contains the code for customization of the post highlight colors. The presets weren't very good, so I added my own:

.thanks_highlight_Level1
{
background: none #240700 !important;
color: {vb:stylevar body_color} !important;
}



.thanks_highlight_Level2
{
background: none #562521 !important;
color: {vb:stylevar body_color} !important;
}

.thanks_highlight_Custom1
{
background: none #bbbbff !important;
color: {vb:stylevar body_color} !important;
}


.thanks_highlight_Custom2
{
background: none #bbbbff !important;
color: {vb:stylevar body_color} !important;
}


.thanks_highlight_Custom3
{
background: none #bbbbff !important;
color: {vb:stylevar body_color} !important;
}


.thanks_highlight_Custom4
{
background: none #bbbbff !important;
color: {vb:stylevar body_color} !important;
}


.thanks_highlight_Custom5
{
background: none #bbbbff !important;
color: {vb:stylevar body_color} !important;
}

.thanks_highlight_Custom6
{
background: none #bbbbff !important;
color: {vb:stylevar body_color} !important;
}


- Those customs I put there because I needed to add then into Buttons.php in order for them to appear in the adminCP. So, I made a bunch so we'd have more later:
'DarkRed' => 'DarkRed',
'Level1' => 'Level1',
'Level2' => 'Level2',
'Custom1' => 'Custom1',
'Custom2' => 'Custom2',
'Custom3' => 'Custom3',
'Custom4' => 'Custom4',
'Custom5' => 'Custom5',
'Custom6' => 'Custom6',

The Customs1 to 6 aren't used right now, but can be in the future.