zì​shàng'ér​xià

top-down

  1. preposition
    from
    from; since; used in formal or written contexts to indicate a starting point in time or space
  2. shàng adjectivenoun
    upper
    top; higher; superior; better; used to describe something in a higher position or rank
  3. ér preposition
    to
    Indicates a transition or progression from one state or place to another; to; through to.
  4. xià locative
    below
    low place; bottom; underneath; (bound form) used after a noun to indicate a scope, condition, or time