Learn Swedish: Tydligast var kontrasten mellan svart och vitt. - Clearest was the contrast between black and white.

This is a stylistic choice. By moving the predicative adjective (tydligast) to the front, the speaker puts extra narrative emphasis on how clear the contrast was. It creates a dramatic or literary tone, compared to the standard, more neutral word order: Kontrasten mellan svart och vitt var tydligast.

Why does the verb var come before the subject kontrasten?

This is the V2 (verb-second) rule in action. Because the adjective tydligast has been fronted to occupy the first position in the sentence, the verb var must take the second position. The subject kontrasten is then forced to move after the verb.

Why is the color white written as vitt instead of vit?

When colors are used as abstract nouns—meaning they refer to the concept of the color itself rather than describing a specific physical object—they always take the neuter form. Therefore, vit becomes vitt. Svart is also in its neuter form here, but since it already ends in a t, its spelling doesn't change.

Shouldn't it be tydligaste since kontrasten is a definite noun?