How did the conflict between the policy of imperialism and the principle of nationalism lead to war between Austria Hungary and Serbia?

The conflict between Imperialism and nationalism created tensions in the Balkans, where various ethnic groups sought self-determination. Austria-Hungary, aiming to maintain its multi-ethnic empire, opposed nationalist movements, particularly in Serbia, which supported Slavic nationalism. The assassination of Archduke Franz Ferdinand by a Serbian nationalist in 1914 escalated these tensions, leading Austria-Hungary to issue an ultimatum to Serbia. When Serbia's response was deemed insufficient, Austria-Hungary declared war, igniting a broader conflict that contributed to World War I.