Internet Explorer does not recognize CSS classes that work correctly in other browsers

IE can not handle CSS as well as other browsers as well. In your code, two } keys are missing from @media items, so styles after this error are not read correctly. This can happen for other types of errors as well, such as a reserved named class, such as in this case of the OS in English .

Finding errors manually in hundreds of CSS lines is not easy, so it's a good idea to use websites like CSS LINT in which you paste your CSS and it looks for problems in the code, and then try to solve the first error (other errors will probably be detected as a result of the first).