Is there a way to tweak the colours on panel elements

[Peejay]

Have you tried using Panel Preferences? You can access these quite easily by right-clicking in a panel and selecting it from the rightclick menu (there's often a menu entry for the particular item where you right-clicked but you don't want that for this purpose).

When you open it you'll see three tabs and the one named Appearance lets you configure the panel quite extensively. You'll see that Background defaults to 'use system style' but you can replace that with a solid colour or a background image. If you opt for solid colour you'll be able to adjust that further using the Alpha Channel and Opacity options also displayed in the Appearance Tab.

Some variations for individual items is also possible by selecting the Items Tab, then highlighting the item you want to adjust and clicking the settings option on the right hand side (displays as a cogwheel on my display but other icons are used too - tool tips help!).

Panel configurations can offer you hours of innocent fun! I hope this is of some help.