。
She seems to be in good shape today.
Literal
She [topic-は] today [contrast-は] condition [subject-が] good [appears-そうだ].
調子 covers everything from physical health ('how the body's doing') to performance ('how someone's playing today') to the vibe of an ongoing situation ('how it's going'). 調子がいい is a versatile catch-all, very different from 調子に乗る ('get carried away'), where the same word means 'rhythm' and lands a moral warning. The visual evidential ~そう attached to い-adjectives uses an irregular form for いい: 良さそう (not いそう). This 良さ stem also shows up in 良さ that's been borrowed back from 良い for nominalization in fixed forms.