Today is your lucky day…I just added the colour setting option to the Theme Options for that grey bar. Please contact me using the Email Support form or my Contact form and I will send you the new version of Encounters (1.5.7).
As for the Layer Slider tutorials…the tutorial is only to setup the slider with the sample one I have on the demo site. Unfortunately teaching how to use it is not part of the theme because this plugin is an optional third party item and any support such as documentation will have to be from the developer. For Encounters, the only thing I did was create a style template for it which the tutorial is really meant to show how to install that, but also use the import file to get the user setup with the exact demo I have. The rest will be up to the end-user.