Plugin members / social media buttons in IE / menu color


I just started three days ago my wordpress-career. :wink:

my site

at first - when i started the site at the main site (Startseite), then always the menu “Zum Stöbern” is colored in red instead of “Startseite”. When i go to another point in the menu, it changes correctly just the visited site to red.

What can be the reason für this issue?

my second problem ist with IE. with some IE versionsI do not see the social media button. With firefox, chrome or older versions of IE ist works. What can I do?

Third problem ist the color of the background (social button at the top). I want to change in the CSS with this coding

.social-navigation {
  background-color: #333;

but it doesn’t work. The button color works fine, but not the background.

The last problem is with the members plug in in teh widget on the right side. I do not see the password - stars and so I do not know, if I entered signs or not. Can I chage the colour of the password-signs, or could I make them visible?

Thank a lot for the help!