Breakdown of akusentowooru wa shiroi.

Questions & Answers about akusentowooru wa shiroi.
は marks the topic of the sentence.
So in:
アクセントウォールは白い。
the topic is アクセントウォール (the accent wall), and the sentence says something about it: it is white.
A very natural way to understand the structure is:
- アクセントウォールは = as for the accent wall,
- 白い = it is white