The wiki provides templates for common tasks.
Those templates can range from simple to complex, being almost invisible to the end-user to provide a complete harmonized template between articles.
In addition to the visual aspect, using some templates will automatically file and categorize articles in ways indispensable to the end-users.
The icons used are from Breeze, the default icon set of KDE.
Since the icons from Breeze are used, the colours from HIG, which is the Breeze Color Palette are used.
Sometimes, there isn't an icon in the Breeze theme that can be used for the purpose. In this case, alternative free and open source icons can be used. Once a stand-in is used, someone with the necessary skills can create the needed icon in the breeze style.