styles
Firemonkey style hack
FMX framework automatically maintains style loading for Controls which implement StyleLookup property. What would you do, to quickly implement compound control, with automatic styling support, without actually write a "true" component class for it?
Some notes on working with FMX styles
That topic covers the case, when platform and custom styles may be seamlessly used together.
Using distinct elements of standard style in our own GUI elements
Article explains how to use standard style elements to customize LookAndFeel of own GUI elements.