Some css styling do not appear when application is built

Every time I run “ionic serve” or build an APK for the first time, my CSS seems to not apply to some of my attributes. For example, my header title is suppose to have a white color and aligned in the center of my page. But when I run ionic serve for the first time, it shows a black color and its aligned to the left. But when I refresh the page, it fixes it self, same when I build an APK, and wont do it again. How can I go about fixing this issue?