When I pinch a link and drop the cursor (do not click on the link), an unnecessary underscore appears and the color of the link changes, then if you click in an arbitrary place, the link returns to the previous look. The hover and active class did not solve the problem. 
- Without a working example with CSS itself we can hardly help with something - andreymal
3 answers
Your hover and active problem should be solved. If they do not work, then you most likely did not identify them in the css-file. You definitely did not forget that these are not ordinary classes, but PSEVDOclasses? You specify the class yourself through the class attribute. PSEVDOklassy already sewn into the system, they do not need to be defined. And they have not only the name, but also the syntax. The usual classes in the css-file are described like this: a.myclass {...}. Pseudo-classes do not write through a dot, but through a colon: a: active, a: hover. This is only a guess. To say exactly you should look at your code.
a { text-decoration: none;} removes underscores from links completely
Try this code
a, a:hover, a:active, a:focus { text-decoration: none; color: black; /* устанавливаем нужный цвет */ }