Beautiful costumes in your denomination. They are so vibrant and cheerful.
We call them vestments, not costumes :-)
The colors are driven by the Liturgical calendar with specific colors worn during different parts of the year:
http://www.catholic.org/clife/lcolors.php
Yes, they are called vestments and the term “denomination” is not correct either. The Maronites are an Eastern Rite Catholic Church.