Plugin breaks the site design

One of the general idea of WordPress strategy is to split 3 layers of platform service and don’t mix them in one porridge:
1) WordPress core that provide the general functionality
2) Themes that provide all, connected with visual design
3) Plugins that provide the additional functionality.
It’s very important to respect the purpose of functionality of the layers by another layers and don’t impede their functionality except appointed points (like hooks and so on).

So, for all of visual design responsible is theme. It’s an awful practice that some plugins have taken to do, to replace the functions of theme: font size, font color, background color – all it is the prerogative of theme and only theme. Indeed, that plugin can provide some elements that it can be not defined in the theme but not the basic. This means that if someone decided to change, say, font-size he changes it only in one place without necessity to check all hundreds of installed plugins.

1. The main problem with this plugin is that it even doesn’t allow to choose default font and color settings (except font-family), defined in a theme, doesn’t allow to choose transparent color for the tab background. So tabs looks like a blot on a page.
   
   Please, fix it.
2. It would be very appreciable if you removed the stitch from active tab title field and tab description field, because now tab title field looks like buttons disconnected with anything bellow. It’s the case when injecting some css in theme design is reasonable and apreciable because it’s plugin-relatable. (For myself I did it using outline for active tab.)

P.S. of course that I fixed it for myself editing plugin’s style.php. But every the plugin’s update means that I need to make the revision of the changes of this file and return my corrections back.