From the game's encyclopedia
Adult Rulers may choose a Lifestyle, which will in turn allow them to select a Focus and start gaining Perks.
Each Lifestyle has its own type of Experience, which is used to purchase Perks. For example, Experience in the Intrigue Lifestyle is necessary to gain Perks such as Dreadful or Like Weeds in a Garden.
The Lifestyles are:
The game's text for patch 1.20.1.2. Words in blue are entries of the encyclopedia: hover one to read it, as in the game.
Lifestyle is an entry of Crusader Kings III's in-game encyclopedia. The game explains it: "Adult Rulers may choose a Lifestyle, which will in turn allow them to select a Focus and start gaining Perks." The game also links it as Lifestyles. Patch 1.20.1.2, from game/common/game_concepts/00_game_concepts.txt and game/localization/english/game_concepts_l_english.yml.
Source: game/common/game_concepts/00_game_concepts.txt, game/localization/english/game_concepts_l_english.yml and the English localisation, Crusader Kings III 1.20.1.2.