If you find that you set a common class on an element and it doesn't take effect, you should check to make sure that there is not some other style in one of your later stylesheets affecting that same element.
Ọ bụrụ na ịchọta na ị setịpụrụ otu klas na ihe mmewere ma ọ dịghị emetụta ya, ị ga-elele iji jide n'aka na ọ dịghị ụzọ ọ bụla ọzọ n'ime ụdị akpaaka gị ndị na-emetụta otu ihe ahụ.