Here’s an expanded color palette with additional light background colors to complement the existing “Green Harmony” theme:

 <Green Harmony Expanded> 
1. Main Green - 
                            
                            #59BE4C
                         - A vibrant and refreshing green that represents growth and vitality.
2. Soft Mint - 
                            
                            #A8E1B0
                         - A light, soothing mint green that complements the main green with a calming effect.
3. Earthy Brown - 
                            
                            #5B3A29
                         - A deep, rich brown that adds a grounding element to the palette.
4. Sky Blue - 
                            
                            #4CB8E1
                         - A bright sky blue that introduces a refreshing contrast, reminiscent of clear skies.
5. Warm Yellow - 
                            
                            #F6D02F
                         - A cheerful warm yellow that adds a touch of brightness and energy.
6. Light Cream - 
                            
                            #F2F4E6
                         - A soft, warm cream color that can be used for backgrounds, providing a neutral base.
7. Pale Peach - 
                            
                            #FCE2D3
                         - A gentle peach hue that adds warmth and approachability, ideal for backgrounds or accents.
8. Soft Lavender - 
                            
                            #E6D7E7
                         - A light lavender that introduces a subtle, calming touch to the palette, perfect for backgrounds.

This expanded palette maintains the vibrant energy of the original while adding soft, inviting background colors that enhance readability and usability.

Would you like any specific guidance on implementing these colors within your app design? Or do you have any other preferences or requirements for the color application in your shopping app?