。
There was nothing left in the refrigerator.
Literal
Refrigerator [of-の] inside [in-には] nothing was-not-remaining.
何も~ない is the 'nothing' pattern: 何 ('what') + も ('even') + negative predicate. 残る ('to be left, remain') + ~ていない (resulting-state negative) = 'is not in the state of remaining' = 'nothing's left.' The には on 中 doubles the location marker with topic/contrast — 'as far as the inside (was concerned).'