This is an excerpt from Section 23a of the Student Handbook:

"Students are expected to dress in a manner consistent with the academic and social goals of our school. Articles of clothing which are distracting or disruptive to the educational process, which violate common standards of decency and modesty, or which contain obscenities, fighting words, or references to gangs, drugs or alcohol are not acceptable. Extremely brief garments or see-through garments are not appropriate for school. Under garments must not be exposed. Any staff member who feels that a student's attire does not meet these standards may send the student to the Dean for a conference."

SOURCE: http://www.arps.org/hs/FAQ/