CSS Classes for Jetpack elements in 'CSS Stylesheet Editor' not working.

I’ve installed Jetpack & would like to make the following changes to Jetpack related elements i.e. Carousel Gallery & contact form.

However with the CSS classes added to ‘CSS Stylesheet Editor’ in Appearance they don’t have an effect.

Interestingly CSS Classes added to CSS Stylesheet Editor in Appearance for non Jetpack related elements do work.

Changes I’d like to make:
a)
Change the color of the background behind the Carousel slide show from black to gray.

b)
Change the color of the borders round the Carousel gallery thumbnails

c)
Change the color of the text that reads ‘(required)’ that s sits after the names of the Contact form input fields?

Any help much appreciated.