Make up is definitely fine! Most Muslim girls spend a lot of effort on their eye make-up. Afterall that is the only part where it is visible to guys. General rule of thumb, cover your shoulders, your ankles and cleavage. Try to wear looser tops to avoid showing the outline of breasts.
If you have any questions on what to wear when visiting a Muslim country, please feel free to massage me. Enjoy your trip planning!
中文版 Read in Chinese: 摩洛哥 注意事項: 女生 穿著篇 What to wear in Morocco for Ladies?