Tweaked lgsalvati's full flat theme to suit my needs.
1) Added application icon on window decoration
2) Added optional Emerald decoration
3) Added instructions how to install theme :)
1) Increased slider width to 11 pixels to fix buggy looking sliders in plasma widgets
2) Mouse-over only coloration of sliders
1) Active titlebar text changed to dark grey (now it is visible on focused window)
2) Changed general appearance to "standard gradient"
3) Rounding changed to "slightly rounded" (excluded popup menus)
4) Added icons to popup menus (it's much easier to spot some commands with icons ;) )
1) Colored scrollbars
2) Visible window buttons on focused window
3) Visible menu (file, edit etc) text
4) Changed text color to black
5) Removed borders from tooltips
6) Few other minor changes that I cannot remember at the moment :)
All credits for the theme goes to Luigi Salvati, creator of the full flat theme.