The theme supported by the details in the text is: "People’s moods often change with the time of day."
The excerpt describes how Norman Gortsby finds a certain harmony with dusk, which he associates with feelings of defeat and the hidden struggles of individuals who come out during this time. The description of dusk as an hour for "the defeated" indicates how the time of day influences the emotions and perceptions of people, aligning with the theme that moods can change with the time of day.