Theme, a top label in executive fashion, defines this summer by minimalism and simplicity - 'the look of nothing'. In the new season, fashion-conscious women from Milan to New York are paring down and cleaning up, and Theme has created the feeling of early '60s modernism and '70s glamour, re-interpreted in a unique style for the '90s. Theme's wardrobe is filled with classic patterns, puristic tones and enchanting silhouettes to present a wearable look with subtle finishing. The key pieces for spring and summer '97 include lightweight dresses and transparencies that hide no secrets. Lines are slim and tapered. For knitwear there is an strong emphasis on crochet, melting into slinky jerseys. Blazers sport classic- line shoulders with pointed lapels, co-ordinated with high-waisted trousers and frilly blouses in stretched fabrics. Boxy jackets and skirts are chic, less is more presentations lemon, lime and clinically-clean white are mixed tonally for simplicity and purity. For young executives, Theme's Essence collection translates fashion in a more pragmatic approach. Superfluous details give way to a strictly functional line. With a new sort of glamour look, Essence offers a pleasant counterpoint to the new femininity - dressing like a lady.