o3de/Assets/Editor/Styles/AssetImporterWindow.qss

QPushButton#m_deleteButton
{
    margin-right: 60px;
}

QTreeView::indicator
{
    width: 12px;
    height: 12px;
    border: 1px solid rgb(204, 204, 204);
    border-radius: 2px;
}

QTreeView::indicator:checked
{
    background-color: rgb(66, 133, 244);
    image: url(:Icons/CheckMark_Checked.png);
    border-radius: 2px;
    border: 0px;
}

QTreeView::indicator:hover
{
    border: 1px solid white;
}

QTreeView::indicator:checked:hover
{
    image: url(:Icons/CheckMark_Hover.png);
}

QTreeView::indicator:!checked:hover
{
    image: url(:Icons/CheckMark_Unchecked_Hover.png);
}

QTreeView::indicator:!enabled
{
    border: 1px solid rgb(102, 102, 102);
}