Appearance>Styles>whateverstyle>Style Property Groups>Style Properties: Node Icons>Node Icon
Look at property margin, default value: 10px 0px 10px 10px
Change to: 9px 10px 9px 10px (can be done in SP, our task is to use EXTRA)
Inspect element with Firebug as per attached image.
The element we want is in class nodeIcon. Under the style tab it is listed as .node .nodeIcon
To style this icon in EXTRA I would refer to it as .forum_list .node .nodeIcon
This should select all nodeIcons in the forum list and apply the margin change to them.
.forum_list .node .nodeIcon
margin: 9px 10px 9px 10px !important;
And as usual: nothing happens!