Optimize mobile experience

[Chefkeks]

Hey there,

thank you for this great plugin. One thing would be to optimize the experience on phones and other devices with small screens. For example:

.cc-floating.cc-theme-edgeless .cc-message { margin: 2em 2em 1.5em }

could be changed to

.cc-floating.cc-theme-edgeless .cc-message { margin: 0.25em }

to consume less space and improve mobile UX. For sure this will only work if you're not using CDN or prefer local stylesheets and use CDN as fallback. Currently CDN seems to be used as a primary option if I see correct in the cookieconsent.php

Regards. Michael

PS: I could maybe provide a pull request, once I'm done with optimizing it.