Learn Croatian: Zla vještica je živjela u mračnoj šumi. - An evil witch lived in the dark forest.

In storytelling, imperfective verbs like živjeti (to live) are used to set the background scene. It describes an ongoing state—she was living there—before the main events of the story take place. This creates the continuous setting for whatever completed (perfective) actions will happen next.

The dictionary form for "evil" is usually zao, so why is it zla here?

When the masculine adjective zao changes to feminine to match vještica (witch), two things happen. First, it loses the "a" in the middle, which is a common Croatian spelling rule called the "fleeting a". Second, the "o" at the end of the masculine form was originally an "l" that transformed over time, and it changes back into an "l" before adding the feminine "a" ending, resulting in zla.

Why do we say u mračnoj šumi instead of u mračna šuma?

This phrase is in the locative case because it follows the preposition u (in) to indicate a static location—where the witch lived. For feminine words in the locative case, the noun šuma (forest) changes to šumi, and the adjective mračna (dark) changes to mračnoj.

je is an enclitic (a weak word that takes the second position). Why is it the third word in this sentence?